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8/10/2019 The Philippine Electronics Code Volume 1 (Safety)
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I. GENERAL RULES
1.1 PURPOSE OF RULES
1.2 APPLICABITY OF RULES
1.2.1 CONSTRUCTION AND RECOSNTRUCTION
A. SERVICE DROP
B. SUBORDINATE ELEMENT
C. REPLACEMENT
1.2.2 MAINTENANCE OF PLANT
1.2.3 CONSTRUCTION PRIOR TO THIS CODE
1.2.4 RECONSTRUCTION OR ALTERATION
1.3 SCOPE OF RULES
1.4 EQUIVALENTS
1.5 LIMITING CONDITIONS REQUIRED
1.6 EXEMPTIONS OR MODIFICATIONS
1.7 SAVINGS
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SECTION I
GENERAL RULES
1.1
PURPOSE OF RULES
The primary purpose of these rules is to establish, for the Republic of Philippines, uniform standards,
regulations and requirements for Electronics and Communications Design, planning manufacture,
production, fabrication, construction, installation, operation, and maintenance, the application of which
will insure adequate protection and safety to persons therein engaged and as well as in the provision,
operation and use of electronics and or communications components, devices, equipment, systems, plants,
stations, services, and or facilities. Application of the rules will also establish an acceptable level of
protection for electronics and communication devices, equipment, and plant from damages due to
electrical and/or physical hazards.
1.2APPLICABILITY OF RULES
These rules apply to all electronics and/or communications design, planning, construction,
installation, manufacture, production, fabrication, operation, and maintenance, which comes within the
jurisdiction of this Code, located indoor or outdoor, terrestrially or extra terrestrially.
1.2.1
Construction and Reconstruction
The requirements apply to all devices, equipment, and plant constructed hereafter and shall become
applicable also to such components, equipment, devices, stations, plants, facilities, system and/or services
now existing, or any portion thereof whenever they are reconstructed.
The reconstruction of an element of a plant, station, system, or service requires that all elements
subordinate to the reconstructed element meet the requirements of these rules.
For the purpose of this Code, reconstruction will be constructed to mean that work which in any way
changes the identity of the station or plant or which it is performed excepting:
A. Service Drop
Service drops may be added to existing plant without necessitating changes in the circuit for
which they are originated.
B.
Subordinate El ement
An element added to an existing plant shall meet all requirements of these rules but does not
require any change in like elements already existing except where the added element is related to
existing like element. The plant or structure to which any subordinate element is added shall meet the
strength/safety factor.
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C. Replacements
Replacement of poles, towers, structure, or supports is considered to be reconstruction and
requires adherence to all strength and protection of this Code.
1.2.2
Maintenance of Plant
The plant or station shall be maintained in such condition to provide safety levels not less than the
minimum specified in rule 4.3.3. The plant or station, or portions thereof, constructed on or after the
effective date of this Code shall be kept in conformity with the requirements thereof.
The restoration of clearance and protection levels originally establish prior to the effective date of this
Code, where the original clearance or protection has been reduce by additional sagging or other causes, is
not considered reconstruction and the reestablish clearance or protection shall not be less than the original
clearance or protection at the time the plant or station was established. The changing of clearance or
protection for any other purpose is reconstruction and clearances or protection so changed shall comply
with the rules of this Code applicable to reconstruction.
1.2.3
Construction prior to the Code
The requirement of this Code, other than the requirement specified in Rules 1.2.2 and 1.2.4 do not
apply to plant or station constructed or reconstructed prior to the effective date of this Code. In all other
particulars, such plant or station or portions thereof shall conform to the requirements of the rules in effect
at the time of their construction or re-construction.
1.2.4 Reconstruction or Alternation
The Commission thru the appropriate government instrumentalities may order reconstruction or
alteration of existing plant or station or portions thereof whenever strength and electrical protection
requirement of this Code are not met and when public interest so requires.
1.3
SCOPE OF RULES
These rules are not intended as complete construction specifications, but embody only the
requirements which are most important from the standpoint of safety and protection. Construction shall be
according to accepted or established good practices for the given local conditions in all particulars not
specified in the rules.
1.4
EQUIVALENTS
Wires sizes specified in this Code may be substituted with its nearest metric equivalent. Copper wiremay be substituted with aluminum, copper clad steel, or other make/materials provided the current-
carrying capacity is identical.
Flat or braided copper may be substituted for round or stranded copper wire provided the current-
carrying capacity is not less than that of the latter.
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1.5
LIMITING CONDITIONS SPECIFIED
The requirement specified in these rules as to clearance, strength and protection are limiting
conditions expressed as minimum or maximumvalues, as indicated. In cases where two or more
requirements establish limiting conditions, the more or most stringent condition shall apply, thus
providing compliance with other applicable conditions. Greater strength of construction, more ample
clearances and higher protection level may be desirable or practical in some cases, and may be provided
accordingly if other requirements are not violated in so doing.
1.6
EXEMPTIONS MODIFICATIONS
If in a particular temporary and emergency case wherein a special type of construction, exemption
from or modification of any of the requirements herein is desired, the Commission shall consider an
application for such exemption or modification only when accompanied by a full statement of conditions
existing and the reason why such exemption or modification is asked and is believed to be justifiable. It is
to be understood that unless otherwise ordered, any exemption or modification so granted shall be limited
to the particular case or the special type of construction specifically covered by the application.
1.7SAVING CLAUSE
The Commission reserves the right to change any of the provisions of this Code in specific cases
when, in the Commissionsopinion, public interest shall be served by so doing.
Compliance with these rules and regulations shall not relieve a utility firm, entity, person or group of
persons from compliance with any statutory requirement.
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SECTION II
DEFINITIONS OF TERMS AS USED IN THE RULES
OF THIS CODE
This section defines technical terms as used in the rules of this Code. The meanings of some terms differ
with the field in which they are used, thus requiring more than one definition. Definitions contained in
this section have been restrictively worded to emphasize the special purpose they are used in this Code.
ACCESS
ACCESIBLE
ACCESSIBLE PART
ACCESSORIES
ACOUSTICS
ACOUSTIC SHOCK
AGING
AIR GAP
ALARM
ALIVE
ALPETH
A point of entry or a means of entry into a circuit.
Admitting close approach because not guarded by locked
doors, elevation or other effective means.
A part so located that it can be contacted by a person, either
directly or by means of a probe or tool, or that is not
recessed the required distance behind an opening.
Devices that performs a secondary or minor duty as an
adjunct or refinement to the primary or major duty of unit
of equipment.
The science of sound.
The physical pain, dizziness, and sometimes nausea caused
by hearing a sudden very loud sound. The threshold of painis about 120 dBm.
The changes in properties of a material in time.
A separating space between two magnetic materials or
conductors.
A visual or audible signal which alerts personnel to the
existence of an abnormal condition.
To have an electrical potential or charge different from that
to earth.
A type of telephone cable sheath featuring a corrugated
aluminum tape applied longitudinally and a polyethylene
jacket overall.
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AMERICAN WIRE GAUGE
(AWG)
AMPERE-HOUR
ANCHOR
ANHYDROUS
ANTENNA
APPLIANCE
ARRESTER
ARRESTER GAS-FILLED
ASSEMBLY
ATMOSPHERE,
EXPLOSIVE
ATTACHMENTS
AUDIO
AUTOMATIC
A scale of cross sectional measurement for non-ferrous
(copper, bronze, aluminum, etc.) wires.
The quantity of electricity represented by a current of one
ampere that flows for one hour.
Any device which holds something secure; a device buried
in the ground to which anchor rods and guys are fastened.
Dry; containing no water.
A means for radiating or receiving radio waves.
Any device that uses or needs electrical or usually an
electric current supply to perform a certain function or
operation; any equipment, usually complete in itself, that
transforms electric energy into another form usually aural,
visual, heat, or motion at the point of utilization.
Device which diverts high transient voltage to ground and
away from the equipment thus protected; the voltage
limiting portion of a protector.
Protector consisting of opposing spaced metal electrodes
within a sealed tube or enclosure filled with gas such as
neon or argon.
A grouping of components to accomplish a particular
function.
Air holding in suspension dust, metal particles of
flammable gas in such proportions that may ignite
explosively.
All of the plant elements (cables, cross-arms, brackets, etc.)
which are fastened to a supporting structure such as a pole.
Pertaining to frequencies which can be heard by the human
ear.
Describing the actions of a device or equipment which are
taken without human supervision in response to certain to
pre-determined conditions.
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BACKBONE
BANDWIDTH
BASEBAND
BATTERY
BOND
BUS
CABLE
CIRCUIT
CLIMBING SPACE
CONDUCTOR
COMMUNICATION
The main system route, usually the route carrying the
majority of the traffic, ad often the longest series of
cascaded hops.
Range of frequencies of a device, within which its
performance, in respect to some characteristics conform tosome specified limits; the difference between the upper and
lower limits of the operating frequency of the device.
Band of frequencies occupied by aggregate of all the
information signals use to modulate a carrier.
A group of two or more cells connected together to furnish
current by conversion of chemical, thermal, solar or nuclear
energy into electrical energy. Common usage permits this
designation to be applied also to a single cell.
A low resistance electrical connection between two cable
sheets, between two ground connections or between similar
parts of two circuits.
A conductor or group of conductors, that serves as a
common connection for two or more circuits.
Assembly of insulated conductors into a compact form
which is covered by a flexible, waterproof, protective
covering.
(1) The complete electrical path between terminals over
which telecommunications are provided; (2) A network of
circuit elements: resistances, reactances, semiconductors
etc. to perform a specific function.
The vertical space reserved along the side of a pole or
tower to permit ready access for linemen to equipment and
conductors located thereon.
Anything such as a wire or cable which is suitable for the
carrying of an electric current.
(1) Transmitting and/or receiving of information signals, or
messages between two or more points; (2) the information
thus received.
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FLAME RETARDING
FLASHOVER
FUSE
GROUND
GROUND BUS
GROUND RING
GUY
GUY, OVERHEAD
GUY, ANCHOR
GUY EXPOSED
Property of materials or structures such that they will not
convey flame or continue to burn for longer times than
specified in the appropriate flame test.
A discharge through air, around or over the surface of solid,
liquid or other insulation, between parts of differentpotential of polarity, produced by the application of voltage
such that the breakdown path becomes sufficiently ionized
to maintain an electric arc.
A device used for protection against excessive currents.
Consisting of a short length of fusible metal strip which
melts when the current through it exceeds the rated amount
for a definite time.
A conducting connection, whether intentional or accidental,
by which an electric circuit or equipment is connected to
the earth, or to some conducting body of relatively large
extent that serves in place of the earth.
A bus to which the grounds from individual pieces of
equipment are connected, and that, in turn, is connected to
ground at one or more points.
A configuration of grounding conductors arranged around a
structure such as building, tower footing, tower guy, anchor
etc. normally connected to an earth ground at one or morepoints.
A tension member (of solid or stranded wires) used to
withstand an otherwise unbalance force on a pole or other
overhead lines structures.
A guy extending from a pole or structure to a pole structure
or tree and is sometimes called a span guy.
A guy which has its lower anchorage in the earth.
A guy which has any part less than 2.5 meters from the
vertical plane of any electric power conductor of more than
250 volts.
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MAINTENANCE
MANHOLE
MANUAL
MESSENGER
NOISE
OPERATING CONTROL
PLANT
PLANT, INSIDE
PLANT, OUTSIDE
PRACTICABLE
PROTECTOR
PROTECTOR, CARBON
BLOCK
All of the work required to keep the plant, circuits, lines,
facilities, systems and services up to standards. This
includes testing, trouble clearing, repairing, and replacing
defective elements.
A subsurface chamber, large enough for a person to enter,in the route of one or more conduit runs, and affording
facilities for placing and maintaining in the runs,
conductors, cables, and any associated apparatus.
Operated by mechanical force, applied directly by personal
intervention.
Stranded steel wires in a group which generally is not a part
of the conducting system, its primary function being to
support wires or cables of the system.
Any unwanted disturbance in a communication system
which tends to obscure the clarity and validity of a signal in
relation to its intended end use.
A control, usually a knob, pushbutton or lever, provided to
enable the user to cause the appliance to perform its
intended function, without the use of tools, when the
appliance is in normal operating condition.
A general term applied to the whole or portion of thephysical property of a communication company which
contributes to the furnishing of communication service.
All plant which is inside of building.
All plant which is out of doors not in building, such as
poles, conduits cables, etc. installed overhead or
underground.
Capable of being accomplished by reasonably available and
economic means.
A device which provides protection from over-voltage
and/or over-current.
A protector whose voltage limiting element utilizes carbon
blocks.
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PROTECTOR, GAS TUBE
QUALIFIED
RADIANT ENERGY
RADIATE
ROD, GROUND
ROD, LIGHTNING
RECONSTRUCTION
SERVICE DROP
SAG
SPAN
SUPPLY CIRCUIT
SYSTEM, ELECTRONIC
TELECOMMUNICATION
A protector whose voltage limiting element employs
electrodes in a gas filled (neon, argon, etc.) envelope.
Persons trained and authorized for the construction,
maintenance and operation of the apparatus, circuit or
system and responsible for the safety precautions involved.
Any energy which radiates in the form of radio waves,
infrared (heat) waves, light waves, X-rays, etc.
The spreading out of radiant energy.
A metallic rod, driven into the ground to provide an
electrical connection to the earth.
A metallic rod carried above the highest point of a pole or
structure and connected to earth by a heavy copper
conductor intended to carry lightning currents directly to
earth.
That work which in any way changes the identity of the
plant or stations or portions thereof.
The installation from the terminal on the pole to the
protector at the customer premises.
The maximum departure, measured vertically, of a wire orcable in a given span from a straight line between the two
points of support of the span at 60 C and no wind loading.
The horizontal distance between two adjacent supporting
points of a cable or wire.
The branch circuit supplying electrical energy to the
equipment or appliance.
A configuration or arrangement of one or more electronic
equipment producing the desired performance.
Any transmission, emission or reception of signs, signals,
writings, images, sounds or intelligence of any nature by
wire, radio, visual, or other system that may in the future
become known or developed.
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TENSILE STRENGTH
TENSION
TENSION, MAXIMUM
ALLOWABLE
TENSION, MAXIMUM
WORKING
TOWER DISPLACEMENT
TOWER SWAY
TOWER TWIST
UNDERGROUND
WORKING SPACE
The pulling stress required to break a material, such as a
wire, express in kilograms of stress per cross-sectional area.
Mechanical stress caused by forces which tends to stretch
or severe the material stressed.
One half of the tensile strength for the messengers guys,
etc. and one fourth of the tensile strength for
communication cables and wire.
The tension resulting under theconstruction arrangement
with the maximum loading conditions specified in section
4.
The horizontal displacement of a point on the tower axis
from its no-wind load position at that elevation.
Tower sway at any specified elevation shall be defined as
the angular displacement of a tangent to the tower axis at
the elevation from its no-wind load position at that
elevation.
Tower twist at any specified elevation shall be defined as
the horizontal angular displacement of the tower from its
no-wind position at that elevation.
Describing communication facilities installed below thesurface of the earth.
The space extending laterally from the climbing space,
reserved for working below, above between conductor
levels; the space surrounding a device or equipment.
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III. GENERAL ELECTRICAL PROTECTION AND
GROUNDING REQUIREMENTS
3.1 GENERAL
3.1.1 Objective
3.1.2 Lightning
3.1.3 Power Contact / Induction
3.1.4 Acoustic Shock
3.1.5 Electric Shock
3.2 PROTECTION METHODS
3.2.1 Shielding
3.2.2 Voltage Limiting
3.2.3 Current Limiting and Interrupting
3.2.4 Grounding
A. Purpose
B. Ground Resistance
C. Made Ground
3.3 METHODS AND MATERIALS
3.3.1 Lightning Rods
3.3.2 Fuses
3.3.3 Surge Arrester
3.3.4 Grounding and Bonding
3.4 MEASUREMENTS
3.4.1 Ground Resistance Test Methods
3.4.2 Earth Resistivity
3.4.3 Determining Good Electrode Location
3.4.4 How to Improve Grounds
3.5 MAINTENANCE AND INSPECTION
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SECTION III
GENERAL ELECTRICAL PROTECTION AND
GROUNDING REQUIREMENTS
3.1 GENERAL
Electrical protection measures covered in this Code are directed against the effects of lightning,
accidental contact with power lines, voltages/electromagnetically/electrostatically induced into
communication circuits by normal or fault currents in parallel runs of power lines and, also, local earth
potential rises due to the flow of lightning or power fault currents.
3.1.1 Objective
Communication systems are subject to electrical hazards from exposure to lightning and power
systems and unless adequate protection measures are employed, such exposures may result in loss of life,
service interruptions and excessive maintenance expense.
A. The primary considerations of electrical protection are:
a) to minimize, as far as practicable, electrical hazards to persons engaged in construction,
operation, maintenance or use of communication systems;
b)
to reduce, as far as practicable damage to equipment and plant;
c)
to eliminate, as far as practicable, any fire hazard resulting from the operation of
communication systems; and,
d) to minimize, as far as practicable, acoustic shock hazards to anyone using communication
services.
B. The amount of protection to be adopted and employed is determined by a proper balance
between:
a) the cost of protection measures employed plus the amount required to maintain the
protection level and adopted; and,
b) the value of damage to or loss of life and property and/or that of service interruptions
caused by electrical hazards.
C.Protection measures may be more costly or impractical to add on or to an operating plant, so, it is
desirable to consider protection requirements in the initial setting-up of the plant.
D.The standards specified in the Code evolves around optimum protection, explain in 3.1.1.B, but
sometimes the state of the art progresses and new techniques evolve that meet the intent of the Code
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much more effectively that its own specific requirements, and in such cases, additional protection may
be use provided no provision in this code is violated.
E. When the safeguarding od human life is involved, even if not actually required by this Code,
communication entities should update its practice voluntarily and as soon as possible rather than wait
for the revision.
3.1.2Lightning
Lightning is an electrical discharge which occurs between clouds and also from cloud to earth. It is
latter type of discharge that is of concern in this Code.
A.
Lightning surges can appear in various parts of a communication system and produce explosive
effects, dielectric failure and fusing of conductors.
B. The path lightning takes depends upon the impedance presented to its wave front. With a wave
that rises from zero to crest value in from 1 and to 10 micro-seconds, the wave front appears to be a
signal whose frequency is from 25 to 250 KHZ.
C. Lightning behaves very much like radio frequency voltages and as much as such its behavior
can be predicted fairly accurately and protection measures can be selected, considering this
characteristic.
D.
Lightning surges may reach indoor equipment and circuits thru exposed portions of the
communication system such as antenna towers, transmission lines, telephone cables, etc. Lightning may
reach buried plants by a direct stroke on portions of the plant exposed above ground and by arcing to
the plant from ground thru plant, trees, man-made structures or the ground itself.
3.1.3. Power Contact/I nduction
The necessity for constructing power and communications facilities near each other and the
advantages to both interest of joint occupancy of poles and support structures present power
contact/induction problems that must be carefully considered.
A. Good construction and adequate spacing between power and communication facilities are the
first line of defense against power contact and power induction hazards. This essentially keeps foreign
potential out of the communication plant.
B. The second measure is to provide paths to ground on the communication facilities sufficient to
prevent excessive voltage rise in the communication plant and utilization of current limiting devices.
C. Insulation on communication conductors may in many instances withstand secondary power
potentials but dependence on insulation alone introduces a considerable hazed.
D. Where the possibility of a power line contact is eminent, equipment connected to such lines shall
be provided with protectors capable of discharging sufficient current to fuse the line conductor, or they
shall be provided with lines fuses and surge arresters. Such protectors shall be adequately grounded to
prevent excessive rise in potential at the equipment locations.
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E. Communication control circuits to electric power stations are always required to function more
so during periods when there are faults on the power systems, so adequate protection is required.
F. A disturbance affecting communication circuits serving electric power stations is ground
potential rise at the power stations. This potential is developed between the power station ground and
the remote ground during periods when large ground currents, such as phase to ground fault currents are
flowing in the station ground. The magnitude of this potential is the product of the ground current and
the ground impedance.
G. Isolating transformers and/or neutralizing transformers and or other appropriate devices should
be utilized to prevent disturbance in communication circuits exposed to a rise in ground potential.
3.1.4Acoustic Shock
Acoustic shock results from an abnormally high sound level, the physical effects of which may vary
from minor discomfort to serious injury.
A. Voltage surges on the communication plant initiated by foreign potential, principally lightning,constitute the major hazard, although switching transients may also be the cause.
B. To reduce the effect of acoustic shocks, a device consisting of two rectifiers, or other semi-
conductor elements in parallel with opposite polarities, shall be connected across the telephone receiver
or headset.
C.The device shall meet the following:
a) It should occupy a small space, so that it can be placed, for example, in the case of the
telephone receiver capsule.
b) Its electrical characteristics should not show significant changes under the temperature andhumidity conditions to which it is subjected in service.
c) It should not degrade the performance of the circuit it is connected to.
d) It should operate such that the amplitude of the sound pressure caused by the diaphragm of
the telephone receiver does not exceed 120 dB above 2 10 -4microbar at 1000 Hz.
3.1.5 Electri c shock
Current through the body rather than voltage of the circuit determines electric shock intensity. Voltage is
significantly only in so far as it is one of the factors determining the magnitude current.
A. Shock current is also dependent on the impedance of the circuit contacted plus the body
impedance of the victim.
B. Studies have shown that the average resistance of a dry adult human body is approximately
1,000,000 ohms. Wet or damage skin reduces this figure and 1,500 ohms is a conservative figure
representing the body resistance for safety calculations.
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C. Ventricular fibrillation is likely to occur when a 60 Hz rms. Current of 0.030 amperes and
above passes through ones chest cavity. Because of this, ANY CIRCUIT FROM WHICH IN
EXCESS OF 30 MA RMS AC OR 90 MA DC CAN BE DRAWN THROUGH A 1500 OHM
RESISTOR (45V RMS AC OR 135VDC) SHALL BE CLASSIFIED AS HAZARDOUS.
D. THE POTENTIAL DIFFERENCE AT ANY TIME BETWEEN ANY EXPOSED
STRUCTURE (EQUIPMENT CABINETS, HOUSINGS, SUPPORTS, ETC.) TO GROUND
(FLOOR, EARTH, ETC.) OR BETWEEN ANY EXPOSED STRUCTURE WITHIN THE REACH
OF AN ADULT PERSON (AOOROX. 1.5 METERS) SHALL BE NO GREATER THAN 45
VOLTS RMS AC OR 135 VOLTS DC.
E. THE POTENTIAL DIFFERENCE AT ANY TIME BETWEEN TWO POINTS ON THE
FLOOR OR EARTH SURFACE SEPERATED BY A DISTANCE OF ONE PACE, OR ABOUT
ONE METER, IN THE DIRECTION OF MAXIMUM POTENTIAL GRADIENT SHALL BE NO
FREATER THA 45 VOLTS RMS AC OR 135 VOLTS DC.
F. The limits specified in 3.1.5 D, and 3.1.5 E concern only the safety of personnel and should not
proper equipment performance.
3.2 PROTECTION METHODS
Rarely will it be economically feasible to meet protection requirements for all situations by means of
basic insulation incorporated in the design of equipment and plant. Additional protection measures are
usually required and may use one or combination of the following basic protection measures.
3.2.1 Shielding
Shielding is the provision of a grounded electrical conducting material located such that foreign potential
will be intercepted and surge currents diverted to ground with the least damage to plant equipmentpossible. Parallel or conductivity is essentially similar to shielding since a parallel conducting path is
provided to absorb surge current which otherwise can flow and cause damage to communication
plant/equipment.
3.2.2 Voltage L imiti ng
Voltage limiting prevents development of hazardous potential difference in communication plant by
direct bonding, when permissible or by use of surge current, discharges gaps, diodes, etc. which operate
under abnormal voltage condition.
3.2.3 Current Limiti ng and Interr upting
Current in a circuit can be kept from rising above a predetermined value by the use of a fuse in series
with the circuit. When current flows through a fuse for a specified time with a magnitude greater that its
rating, the fuse will interrupt the current.
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B. The material for the lightning rod shall be of galvanized iron/steel, copper weld or other
corrosion-resistant material. The material selected shall be resistant to any corrosive condition existing
at the installation or shall be suitably protected against corrosion.
C. Lightning rods shall be mounted atop structures not less than 30 cm. above the highest point of
the structure or not less than 30 cm. above the point which creates an effective electrical height for the
structure and to encompass all other elements, mounted and protruding horizontally from the structure,
within the area explained in 3.3.1 A.
D. A No. 2 AWG grounding conductor connected to the lightning rod shall be run in the shortest
route directly to the master ground bus or direct to earth without intervening splices or connection, free
from sharp bends. Each lightning rod shall require a separate of # 2 AWG grounding conductor.
E.Structures not requiring lightning rod installations are:
a) Structures within the area described in 3.3.1.A. due to nearby taller buildings or structures.
b)Passive reflectors and other similar fully metallic structures. Provided that its footing or aconnection to a separate made ground provides sufficient grounding for the structure and that
provision 3.1.5 D. is not violated.
c) Metallic antenna towers or poles where the antennas and their supports mounted on the
metallic tower or pole have electrical continuity all the way from all elements to the structure and
its footings and where a connection to a separate made ground provides sufficient grounding for
the structures and provided further that provision 3.1.5. D. is not violated.
F. All other structures not covered by provision 3.3.1.E. shall be provided with lightning rod or
rods as required considering provision 3.3.1.C.
G.The grounding system of lightning rods shall not be used as grounding conductors for any part
of a plant.
3.3.2 Fuses and Current Interrupting
Current interrupting may be accomplished by employing one or any combination of the following:
a)Fuse Link (fuses)
b)Heat coils
c)Fuse cable
d)Automatic circuit breaker
A.Fuses are effective only when its time and current operating characteristics are matched to that
of the circuit it is intended to protect.
B. After the fuse has opened, an arc may persist under the influence of excessive voltage. Failure
of the arc to clear rapidly constitutes hazard and defeats the purpose of the fuse.
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C. Fuses are not effective for limiting short duration surges so it becomes necessary to provide
some means of diverting surge currents through other paths having adequate current carrying
capacity.
D. Heat coils that guard against sneak current fire hazard and will carry 0.35 ampere for about
three hours and will operate within 210 seconds and 0.54 ampere.
E. Fuse cables are telephone cable sections installed in series and prior to the plant being
protected and are one size smaller than the section to which they are connected.
F. An automatic circuit breaker is a device which opens the circuit when the current exceeds a
predetermined rating a specified time without causing injury to itself and capable of being reset when
a default condition no longer exist.
G. The choice of current interrupting device or method shall consider the cost of the protection
measure/s against the value of service continuity and cost of system damage but personnel safety shall
never be jeopardized.
3.3.3 Surge Ar resters
Surge Arresters are normally open circuited devices and pass no significant current at normal
operating potentials and shall meet the following fundamental requirements:
A.Striking voltage must be as constant as possible even after several successive discharge.
B. The transition from glow to arc discharge must occur at less than one ampere. Are discharge,
once established, must be very stable, and spontaneous transition from an arc to glow discharge must
never occur.
C.The arcing voltage must be as small as possible.
D.It must be capable of carrying several tens of amperes for periods of the order of one second. It
must be able to repeat such operation several times at very short intervals without its characteristics
being affected.
E.If the above are exceeded, the surge arrester must fail safe, this shall be achieved through
final short-circuiting of the electrodes. The surge arrester must never be destroyed by shattering of the
enveloped in such a way as to leave the electrodes exposed, or by breakage of an internal connection,
since in such cases the circuit is no longer protected and no warning of the fact is given.
F.The choice of breakdown voltage rating of surge arrester shall be as low as may possible beallowed by the facility to which it is to be connected.
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A.The direct method is the simplest way to make an earth resistance test. With this method, resistance
of two electrodes in series is measured theelectrode under test and the reference ground or water system.
There are three important considerations with this test method:
1) The reference ground or water systems must be extensive enough to have negligible
resistance.
2) The water pipe must be metallic throughout without any insulating couplings or flanges.
3)
The earth electrode under test must be far enough away from the water-pipe system to be
outside its sphere of influence.
Fig. 3-1Connections for a direct or two terminal ground resistance test.
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B. The Fall of Potential method uses two reference rods. Placing of the two reference rods is critical
and the instruction of the instrument manufacturer must be followed.
Fig. 3-2 Connections for a Fall of Potenti al or Three Terminal Ground Resistance Test.
Fig. 3-3Fall of potenti al method of testing.
C. Other methods for ground resistance measurements may be used such as Voltmeter-ammeter
Method and Triangular method, provide the limitations of each method are considered and due safeguards
taken.
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B. In soil, conduction of current is largely electrolytic so the amount of moisture and salt content of
the soil radically affects its resistivity. Amount of water in the soil varies with the weather, time of the
year, nature of sub-soil and depth of the permanent water table.
-
Moisture Content Resistivity, Ohm-Cm.
% by weight Top Soil Sandy Loam
0 1000 106 1000 106
2.5 250,000 150,000
5 165,000 43,000
10 53,000 18,500
15 19,000 10,500
20 12,000 6,300
30 6,400 4,200
From: An Investigation of Earthing Resistance by P.J. Higgs I.E.E.E.
Jour., vol. 68, p. 736, Feb. 1930.
Pure water has a high resistivity; naturally-occurring salts in the earth, dissolve in water, lower its
resistivity.
-
Added Salt % by Weight
of Moistur e Resistivity, Ohm-Cm.
0 10,700
0.1 1,800
1.0 460
5 190
10 130
20 100
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C. An increase in temperature will decrease resistivity because water in soil mostly determines the
resistivity and an increase in temperature decreases the relativity of water. This is shown in the following
table.
- EFFECT OF TEMPERATURE ON EARTH RESISTIVITY
Temperature Resistivity, Ohm-Cm.
C F
20 68 7,200
10 50 9,900
0 32 (water) 13,800
0 32 (ice) 30,000
-5 23 79,000
-15 14 330,000
D. Earth resistivity is a very variable quantity and to determine the value at a given location at a
given time, the only sure way is to measure it.
E.The deeper ground electrode gives a more stable and lower value of resistance. Electrodes must
reach deep enough level to provide permanent moisture content and stable temperature.
Determin ing Good Electrode Location
3.4.3A good low-resistance ground electrode depends upon a low-resistivity soil in a location where the
electrodes can be driven. There are two approaches to picking this location:
a) Drive rods in various locations to such depths as may be required and measure the resistances
while the rods are being driven.
b)Measure the earth resistivity before driving ground rods then calculate the number and length of
rods required.
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How to improve grounds
3.4.4When the ground-electrode resistance is not low enough, undertake the following:
A. Lengthen the ground-electrode in the earth
Fig. 3-4 Ear th resistance decreases with depth of electrode in earth .
B. Use multiple Rods.
Fig. 3-5Comparati ve resistance of mult ipl e rod earth electrodes.
Single rod equal 100%
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Fig. 3-6 Ef fect of vari ation i n earth r esistivity wi th depth on the resistance
of a hor izontal ground 150 meters long and 0.4 cm, diameter bur ied
at the sur face.
Fig. 3-7 Vari ation of resistance of vertical ground rod with length for
vari ous diameters as indicated on curves, for an earth r esistivity
of 100 meter-ohms.
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Fig. 3-8 Vari ation of r esistance of hor izontal ground with length ground
at the sur face and at a depth of 30 cm, for an earth resistivi ty of
100 meter-ohms and for a wir e diameter of 0.2E cm (# 10 wire).
Fig. 3-9Var iati on in combine resistance of rods connected in mul tiple when arrange on a straight l ine
or a circle with spacing between rods equal to length of rods. Dashed line indicates combined
resistance without mutual effects. Rod length 240 times rod radius as for 5 ft . rods of inches
diameter.
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IV. GENERAL STRENGTH REQUIREMENTS
4.1 GENERAL
4.2 LOADING ZONES
4.2.1 Heavy Loading Zone
4.2.2 Medium Loading Zone
4.2.3 Light Loading Zone
4.3 SAFETY FACTORS
4.4 TRANSVERSE STRENGTH
4.5 VERTICAL STRENGTH
4.6 LONGITTUDINAL STRENGTH REQUIREMENTS
4.6.1 Reduction in Stress
4.6.2 Use of Guys and Braces
4.6.3 Unbalance Loads
4.7 ULTIMATE STRENGTH OF MATERIALS
4.7.1 Wood
4.7.2 Structural Steel4.7.3 Reinforce Concrete
4.7.4 Conductors, Span Wires, Guys, Messengers
4.7.5 Tower or Pole Foundations and Footings
4.8 DETAILED STRENGTH REQUIREMENTS
4.8.1 Poles, Towers and Other Structures
4.8.2 Crossarms
4.8.3 Pins and Conductors
4.8.4 Conductors4.8.5 Insulators
4.8.6 Guys and Anchors
4.8.7 Messenger and Span Wires
4.8.8 Hardware.
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SECTION IV
GENERAL STRENGTH REQUIREMENTS
4.1 GENERAL
The Section established provisions covering mechanical strength requirements used in conjunction
with electronic equipment or systems either alone or when involved with electrical power systems. The
provisions of this Section are supplemented in many instances by provisions in other sections.
The rules in this Code complement applicable provisions in the Building Code of the Philippines and
the Philippine Electrical Code. The more restrictive or stringent rules shall prevail.
4.2 LOADING ZONE
The following conditions of the temperature and loading shall be used for the purpose of this Code in
determining the strength required by poles, towers, structures, and all parts thereof as well as in
determining the strength and clearances of conductors. More stringent conditions may be used if desired.
4.2.1. Heavy Loading Zone
A. Heavy loading shall apply to those parts of the Republic of the Philippines as shown in Fig. 4-1.
This loading shall be taken as the resultant stress due to wind and dead weight for 240 kilometer per
hour (kph) wind velocity.
a)Wind pressure on protect area on cylindrical surfaces shall be computed as being 60% of that
for flat surface.
Where lattice structures are used, the actual exposed area of one lateral face shall be increased
by 50% to allow for pressure on the opposite face, provided by this computation does not indicate agreater pressure than would occur on a solid structure of the same outside dimensions, under which
conditions, the latter shall be taken.
b)Temperature shall be considered to be 27C at the time of maximum loading. The maximum
temperature shall be assumed as 65C in computing sag under this condition.
B. Medium loading shall apply to those parts of the Republic of the Philippines as shown in
Fig. 4-1. This loading shall be takes as the resultant stress due to wind for 200 KMP wind velocity and
dead weight under the following conditions:
a)Wind pressure on project area on cylindrical surface shall be computed as being 60% of thatfor flat surface.
When latticed structures are used, the actual exposed area of one lateral surface shall be
increased 50% to allow for pressure
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Fig. 4-1Wind Loading Map
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on the opposite face, provided this computation does not indicate a greater pressure than would
occur on a solid structure of the same outside dimensions, under which conditions, the latter shall
be taken.
b) Temperature shall be considered to be 27C at the time of maximum loading. The maximum
temperature shall be assumed as 65C in computing sag under this condition.
C. Light loading shall apply to those parts of the Republic of the Philippines as shown in Fig. 4-1.
This loading shall be taken as the resultant stress due to wind for 160 KHP wind velocity and dead
weight under the following conditions:
a) Wind pressure on protected area on cylindrical surface shall be computed as being 60% of
that for flat surface.
When latticed structures are used, the actual exposed area of one lateral surface shall be
increased 50% to allow for pressure on the opposite face, provided this computation does not
indicate a greater pressure than would occur on a solid structure of the same outside dimensions,
under which condition, the latter shall be taken.
b) Temperature shall be considered to be 27C at the time of maximum loading. The maximum
temperature shall be assumed as 65C in computing sag under this condition.
4.3 SAFETY FACTORS
4.3.1 The safety factors specified in these rules are the maximum allowable ratios of ultimate strengths of
materials to the maximum working stress, except that:
A. The safety factors for structural steel (towers, poles, cross-arms, supports) shall be applied as
specified in Rule 4.7.2 and
B. The safety factors for wood members in bending shall be applied to longitudinal tension and
compression as ratios of the module of rupture to the maximum working stress. The maximum working
stresses used with these safety factors shall be the maximum stresses which would be developed in the
materials under the construction arrangement with temperature and loadings as specified in Rule 4.2.
4.3.2 Lines and elements of lines, upon installation or reconstruction shall provide, as a minimum, the
safety factors specified in Table 4-1 for vertical loads and load transverse to lines and for loads
longitudinal to lines except where longitudinal loads as balanced.
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4.4.1 Special Pr ovisions
Where it is impossible to obtain the required transverse strength except by the use of side guys or
special structures and it is physically impossible to install them at the location of the transversely weak
support, the strength may be supplied by side guying the line at each side of, and as near as practicable to,
such weak support with a distance not in excess of 245 m. between the supports guyed; provided that the
section of the line between the transversely weak structures is weak in regard, to transverse loads only,
that it is in a straight line and that the strength of the side guyed supports is calculated on the transverse
loading of the entire section of line between them.
4.5 VERTICAL STRENGTH REQUIREMENTS
In computing vertical strength requirements, the loads upon poles, towers, foundations, cross-arms,
pins, insulators, and conductor fastenings shall be their own weight plus the superimposed weight which
they support, including that of wires and cables under the loading conditions of Rule 4.2 plus that which
may be added by difference in elevation of supports. The resultant of vertical and transverse loadings on
conductor shall be used in determining the allowable and working tensions or sags in accordance with
Rule 4.2. In addition, a vertical load of 90 kg. at the outer pin shall be included in computing the vertical
loads on all cross-arms. All members of structures shall be constructed to withstand vertical loads as
specified above the safety factors at least equal to those specified in Rule 4.3.2.
4.6 LONGITUDINAL STRENGTH REQUIREMENTS
In computing the longitudinal strength requirements of structures, or any parts thereof, the pull of the
conductors shall be considered as that due to the maximum working tension in them under the loading
conditions specified in Rule 4.2.
4.6.1 Reduction in Stress
Stresses in supporting structures due to longitudinal load may be reduced by increasing the conductor
sags, provided that prescribed conductor clearances in Section VII are maintained.
4.6.2 Use of Guys and Br aces
The longitudinal strength requirements for poles, towers, and other supporting structures shall be met
either by the structure alone with the aid guys or braces. Deflection shall be limited by guys or braces
where such structures alone, although providing the strength and safety factors required, would deflect
sufficiently under the prescribed loadings to reduce clearances below the required values.
4.6.3 Unbalance Loads
Poles, towers, or structures with longitudinal loads not normally balanced (as the dead ends or angles
greater that can be treated as in Rule 4.4) shall be sufficient strength or shall be guyed or braced, to
withstand the total unbalanced load with the safety factors at least equal to those specified in Rule 4.3.
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Tension and Bending: The yield point, 23.2 Kg/mm2shall be divided by the safety factor to determine
the maximum allowable working stress.
Compression: The Maximum allowable working stress shall be calculated by the following formula:
Where Smax= maximum allowable working stress in Kg/mm2
fs = safety factor specified in Rule 4.3
YP = Yield point of the steel. 23.2 Kg/mm2
1 = unsupported length of a member
r = radius of gyration of a member.
Shear: The ultimate tensile strength, 3.876 Kg/cm2 shall be multiplied by 2/3 and divided by the
safety factors specified in Rule 4.3 to determine the maximum allowable working stress.
Where the figures given are used, structural steel shall conform to ASTM A7-39 for carbon steel of
structural quality. Other values may be used for steel of other strength provided the yield point and
ultimate tensile are determined by test.
4.7.3 Reinforced Concrete
Values used for ultimate strengths of reinforced concrete in conjunction with safety factors given in
Rule 4.3 shall not exceed the following:
Reinforcing steel, tensile or compression strength in Kg/cm23867
Concrete, 1:2:3 Age Compression Strength
7 days 63.5 Kg/cm2
30 days 169.00 Kg/cm2
90 days 218.00 Kg/cm2
6 months 310.00 Kg/cm2
If reinforced concrete is designed for higher strength values which are proven by test, such values may be
used in lieu of the figure given.
4.7.4 Conductors, Span Wires, Guys, Messengers
Values used for ultimate strength of wires and cables shall not exceed those given in Tables 10 to 14
in the Appendix. For use of types of wires and cables of other materials or composition not included in
the Appendix, values for ultimate strength similarly derived from specifications of the ASTM shall be
used except that, if such specifications are non-existent, manufacturers specifications may be used
provided that test have been made which shall justify the manufacturers rating for ultimate strength.
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4.7.5Tower or pole foundations and footings
In calculating the resistance of foundations or footings of towers, poles and pole line structures to
uplifts, the weight of concrete shall be taken as not more than 2322.6 Kg/mm3 the weight of earth
(calculated 30 degrees from the vertical) shall be taken as not more than 1441.6 Kg/mm 3. The resistance
of soil to the depression of foundations shall be calculated from the best available data on the soil in
question. In lieu of calculation, the strength of foundations or footings against uplift or depression may be
determined by test under the soil conditions obtaining.
4.8 DETAILED STRENGTH REQUIREMENTS
4.8.1 Poles, Towers and Other Structures
A. Strength
Wood poles shall be sound timber, free from defects which would materially reduce their strength
or durability and they shall have sufficient strength to withstand, with safety factors not less than those
specified in Rule 4.3, the maximum stresses to which they are subjected under the loading conditionsspecified in Rule 4.2. The modulus of rupture used in calculation and safety factors shall be not greater
than the value given in Rule 4.7.1.
Steel and reinforce concrete poles, together with their foundations, shall be such material and
dimensions as to withstand, with safety factors not less than those specified in Rule 4.3, the maximum
stress to which they are subjected under the loading conditions specified in Rule 4.2. The fiber stress
values used in calculation of safety factors shall be specified in Rules 4.7.2 and 4.7.3.
Certain poles are subject to special stress due to angles in the line, dead ending of conductors, or
other attachments, which stresses must be included in computing the loading and safety factor. Poles
subject to these special stresses sometimes require the use of guys, in which case the pole below thepoint of guy attachment shall be considered merely as a strut, the guy taking all lateral stresses. In such
cases, the pole strength requirements shall apply at the point of guy attachment rather than at the ground
line. Spliced or stub reinforced poles or pole top extensions, including the attachments (joints) of
different members involved, shall meet all of the vertical, transverse and longitudinal strength
requirements of these rules as if a whole pole were used.
B.Setti ng of Wood Poles
The depth of pole setting given in Table 4-3 are applicable to wood poles set in firm soil or in solid rock.
Where the soil is not firm, deeper settings or special methods of pole shall be resorted to. Where unguyed
poles are set subject to heavy strain, or at corners or curves, a greater depth shall be used. Guyed poles
may be set more than 0.3 meter less than the depths specified in Table 4-3 provided the guys do not
assume any normal working load under condition of no wind and the resulting depths of setting are not
less than 1 meter.
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Table 4-3
Total Length Depth in Depth in
of Pole, Meter Soil , Meter Rock, Meter
6.0 1.2 1.0
7.5 1.4 1.0
9.0 1.5 1.0
10.5 1.5 1.0
12.0 1.7 1.0
13.5 1.8 1.2
15.0 2.0 1.2
17.0 2.0 1.4
18.0 2.0 1.4
20.0 2.3 1.5
21.0 2.3 1.5
23.0 2.5 1.724.5 2.5 1.8
C. Gains
Gains or equivalent means may be provided for increasing surface contact of cross-arms with sound
wood poles. Where gains are cut, the depth shall be not less than .5 mm. or more than 5 mm. Slab
gains, metal gains, pole bands, or assemblies of wood or metal supports that provide suitable surface
contact and adequate strength are permitted.
4.8.2 Cross-arms
A. Material
a. Wood shall be of suitable grades listed in Table -2 or other accepted species.
b. Metal shall be structural steel, cast steel, or malleable cast iron, properly galvanizedor
otherwise protected to resist corrosion, or may be of any corrosion-resisting metal or alloy.
B. Minimum Stress
a. Wood shall have a cross section not less than .5 .5cm except that cross-arm 2 meter
or less in length may be 7 9.5 cm.
b.Metal the physical properties as a result of dimensions, shape and cross-sectional area ofmetal cross-arms shall be such as to result in sufficient strength to meet the requirements of Rules
4.5, 4.6, 4.7.2 provided the thickness of any element shall be not less than 0.23 cm.
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C.Strength
Cross-arms shall be securely supported by bracing, where necessary to withstand unbalance vertical
loads and to prevent tipping of any arm sufficiently to decrease clearances below the values specified in
Section 7. Such bracing shall be securely attached to poles and cross-arms. Supports in lieu of cross-
arms shall have means of resisting rotation in a vertical plane about their attachment to poles or shall be
supported by braces as required for cross-arms. Metal braces or attachments shall meet the requirements
of Rule 4.7.2 and 4.8.8. In computing the strength requirements to meet vertical loads, the effect of such
bracing may be considered.
(1)Where longitudinal loads are normally balanced, cross-arms supporting conductors shall have
sufficient strength to withstand a load, applied in the direction of the conductors at the outer pin
position of 180 kg. with a safety factor of not less than unity.
(2)Where cross-arms are subjectedto unbalanced longitudinal loads they shall have sufficient
strength to meet the strength requirements with safety factors at least equal to those specified in
Rule 4.3. At unbalanced corners and dead ends, where conductors are supported on pins and
insulators, double cross-arms shall be used to permit conductor fastenings at two insulators and thus
retard slipping.
D. Replacements(See Rule 4.3.3).
4.8.3 Pins and Conductors Fastenings
A. Material
1. Pins Insulator pins shall be of galvanized iron or other corrosion-resisting metal or of other
suitable material
2. Fastenings Conductor fastenings shall be of galvanized steel, galvanized iron or other
corrosion-resisting metal.
B.Size
1. Wood Pins The minimum diameter of the shank shall not be less than 0mm.
2. Metal Pins The minimum diameter of the shank shall not be less than .5 mm.
3.Fastenings and Tie Wires Fastenings and tie wires shall have not sharp edges at points of
contact with conductors, and shall be applied in such a manner so as not to damage the conductor.
The materials and minimum sizes of tie wires for the various sizes and types of conductor shall beshown in Table 4-4. Flat wire having a cross-sectional area not less than that of round wire of the
gauge specified for tie wires may be used.
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Table 4-4
SIZE AND MATERIAL OF TIE WIRE
L ine Conductor Tie Wir e
Mater ials Size Size Mater ial s
Copper, bronze 6AWG Same as line Soft copper or
Copper-covered smaller conductor annealed copper-
steel or composites 4AWG 6AWG covered steel
of any of 2AWG or 4AWG
them larger
Galvanized iron or 10BWG and Sames as line Soft galvanized
galvanized steel smaller conductor iron or galvanized
9BWG 10BWG steel
8BWG 9BWG
4 & 6BWG 8BWG
Aluminum or 4AWG Same as line Soft aluminum
ACSR smaller conductor
2AWG or 4AWG do
larger
C.Strength
Insulator pins and conductor fastenings shall be able to withstand the loads which they may be
subjected to with safety factors at least equal to those specified in Rule 4.3.
1. Longitudinal loads normally balanced:
a) Insulator Pins Where longitudinal loads are normally balanced, insulator pins which
support conductors shall have sufficient strength to withstand, with a safety factor of not less
than unity, a load at the conductor position of 180 kg.
b)Conductorfastenings Where longitudinal loads are normally balanced, the tie wires or
other conductor fastenings shall be installed is such a manner that they will securely hold the
line conductor to the supporting insulators and will withstand without slipping of the conductor,
unbalanced pulls of 15% of the maximum working tensions but not more than 120 kg.
2. Longitudinal loads normally unbalanced At unbalanced corners and dead ends where the
conductor tensions are held by cantilever strength in pin-type insulators and pins, double pins and
insulators shall be used and each line conductor shall be tied or fastened to both insulators so as to
prevent slipping of the conductor under the maximum working tensions with a safety factor of 2
under the temperature and loading conditions specified in Rule 4.2.
D. Replacements(see Rule 4.3.3).
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4.8.4 Conductors
A. Material
Conductors shall be of copper, copper-covered steel, bronze, stranded cable composites of any of
the foregoing, aluminum, aluminum cable steel reinforced, galvanized iron, galvanized steel or of other
corrosion-resisting metal not subject to rapid deterioration.
B. Size
Size of conductors for various types of construction and service is specified in Selection 5 & 7.
C. Strength
1. Conductor shall have sufficient strength to withstand, with safety factors not less than those
specified in Rule 4.3, the maximum stresses to which they are subjected under the loading
conditions specified in Rule 4.2.
2.Sags and Tensions Conductor sags shall be such that in loading conditions specified inRule 4.2 the tension in the conductor shall not be more than one-half the breaking strength of the
conductor. The use of sags greater than the allowable minimum may be desirable in order to reduce
working tensions.
3.Splices Splices in conductors shall be in accordance with the requirements of Table 4-1
except as provided in Rule 4.7.4.
4. Service drops for telephone, data, etc. of No. 16 AWG paired copper wire maybe used,
provided they do not cross over power lines, trolly contact or feeder conductors of railways and the
like. Paired high strength service drops of No. 18 AWG high strength bronze or high strength
copper-covered steel may be used provided the breaking strength of the pair is not less than 155 Kg.
D.Replacements(see Rule 4.3.3).
4.8.5 I nsulators
A. Line
Insulators, supports, clamps, and other miscellaneous attachments shall be designed to
withstand, with at least the safety factors specified in Rule 4.3, the mechanical stress to which they
are subjected by conductors, wires or structures, under the loading conditions specified in Rule 4.2.
Pin insulators shall effectively engage the thread of the pin for at least two and one-half turns.
B. Guy
Guy insulators, including insulators in messengers, shall have mechanical strength at least equal
to that required of the guys in which they are installed.
C. Replacements(see Rule 4.3.3).
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4.8.6 Guys and Anchors
A. Material
The exposed surface of all guys and guy rods shall be of corrosion-resisting material.
B. Size
The size and strength of guys shall be not less than as specified in Table 4-5 and shall also be such
as to provided safety factors not less than those specified in Rule 4.3, for the loads imposed by the
construction under the loading conditions specified in Rule 4.2.
Table 4-5
MINIMUM SIZE AND STRENGTH OF GUYS
M inimum Size
Materi al of Strand Anchor, Guys Overhead Guys
1. Galvanized Steel 8 mm 6.5
Common or Siemens
Martin
High Strength or 6.5 m 5 m
Extra High Strength
2. Copper-covered Steel 3 No. 9AWG 3 No. 10AWG
3. Bronze 6.5 mm 3 No. 10AWG
Minimum Allowable 1454.54 Kg. 863.63 Kg.
Ultimate Strength (3200 lbs.) (1900 lbs.)
of Guys
C. Strength
When guys are used with poles or similar structures, capable of considerable deflection before
failure, they shall be able to support the entire load, the pole below the point of guy attachments acting
merely as a strut. Stranded wires shall be used when the ultimate strength of the guy exceeds 820 Kg.
Anchor rods and their appurtenances shall meet the same strength requirements as the guy wire or
strand (see Rule 4.3)
D. Replacements(see Rule 4.3.3).
4.8.7 Messengers and Span Wires
A. Material
Messengers and span wires shall be stranded of galvanized steel, copper-covered steer or other
corrosion-resisting material not subject to rapid deterioration.
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B. Strength
Messengers and span wires shall be capable of withstanding, with safety factors as specified in Rule
4.3.; the tension developed because of the load they support combined with the loading conditions
specified in Rule 4.2. An allowance of 90 Kg. of vertical load for a man and cable chair shall be made
in computing tensions in messengers and span wires which supports cable except in the case of short
spans which are not required to support workman. The strength of guys supporting messenger loads
shall be such that the safety factor of such guys is not less than the safety factor required of the
messenger as specified in Rule 4.3. It is recommended that overhead guys shall be the same size as the
suspension strand to compensate for the angle between the plane of the horizontal load of the
suspension strand and the line of the guys.
C. Supports
Messenger supporting cables shall be attached to poles or cross-arms with hardware which provides
safety factors at least equal to those specified in Rule 4.3, based on the weight of the cable plus an
allowance of 90 kg. for the man and cable hair. All hardwares subject to injurious corrosion shall be
protected by galvanizing, or other suitable treatment.
D. Replacements(see Rule 4.3.3).
4.8.8 Hardware
All pole line hardware shall be galvanized, otherwise protected by a corrosion-resisting treatment,
or shall be composed of material which is corrosion resistant.
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V. INDOOR PLANT SAFETY RULES
5.1 GENERAL RULES
5.2 RADIO TRANSMITTING & RECEIVING INSTALLATION
SAFETY REQUIREMENTS
5.2.1 Fixed Station Installation
5.2.2 Mobile Station Installation
5.3 SWITCHING EQUIPMENT INSTALLATION SAFETY
REQUIREMENTS
5.4 COMPUTER AND DATA INSTALLATION SAFETY
REQUIREMENTS
5.5 STATION INSTALLATION SAFETY REQUIREMENTS
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SECTION V
INDOOR PLANT SAFETY RULES
5.1 GENERAL RULE
This Section establishes safety rules for all electronics and communications equipment installed
and/or located inside buildings or in sheltered structures, except consumer products.
5.1.1 All electronics and communications equipment except consumer products installed and/or located
inside buildings or in sheltered structures shall be engineered, installed, operated and maintained in such a
manner that SHOCK CASUALTY or FIRE HAZARD shall not result when normally used and operated.
5.1.2 A grounding system shall form a part of all indoor electronics and communication installations
falling under any of the following category:
A. When any equipment is powered from 110 V. A.C. or higher;
B. When an outdoor exposed facility is connected to any equipment for its normal operation;
C. All radio stations, telephone/telegraph/telex exchanges and fixed computer installations.
5.1.3 The grounding system shall be designed to direct foreign potentials and surge currents in the
shortest route possible to earth.
5.1.4Potential rise on accessible parts shall be no greater than the values specified in rule 3.1.5 C.
5.1.5Strength consideration for indoor equipment installation shall be sufficient to assure that no casualty
hazard shall result from falling or collapsing equipment or their components.
5.1.6 Operation of electronic and communications equipment shall not result in emission of fumes,
chemicals, radiations, etc. to such a level considered hazardous by those recognized by the government to
make such assessment.
5.1.7 Users of electronics and communication system or services shall be protected from shock or fire
hazards attendant to the use of the service.
5.1.8 It shall be the users responsibility to ascertain that adequate internal protection is built into the
equipment by the supplier in such a manner that no shock or fire hazard shall result when the equipment
is operated within its rating.
5.1.9 The electrical protection measures shall coordinate with the inherent dielectric strength and surgecurrent carrying capacity of the equipment or system being protected.
5.1.10Only approved protectors and other electrical surge protection devices shall be used.
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5.1.11The amount of protection for the equipment to be designed into the system is dictated by the value
of service continuity and repair cost attributed to damages in the absence of the protection measure
against the cost of installing and maintaining the protection measures. Safeguarding of persons shall be
the foremost factor in the design and consideration of protection measures.
5.1.12Fuel tanks shall not be located between antenna towers and the radio building.
5.1.13 The building ground ring conductor shall be buried not less than 0.3 meters below grade level and
between 0.3 and 0.5 meters from the foundation. The building ground rods shall be spaced not more than
6.0 meters apart around the building.
5.1.14Where ground wires cross each other, they shall be bonded together to prevent arcing.
5.1.15Points with potential in excess of that specified in rule 3.1.5 as hazardous voltages may be made
accessible as may be required for testing/maintenance purposes by removal of shields or barriers so
marked indicating that its removal will expose hazardous voltage. The voltage of the part to be exposed
shall be indicated in the same marking with further instruction to return the shields or barriers after the
work.
5.1.16 When working on points specified in Rule 5.1.15, extreme caution shall be exercised and the
following observed:
A. Use tools with insulated handles;
B. Place rubber mats or equivalent on the floor where the persons required to access such points
may stand on;
C. Only authorized, competent persons shall be allowed to undertake work that may expose them
to such hazardous voltages.
D. No person shall undertake such work alone.
5.1.17Circuits and components capable of retaining an electrical charge after the power to the equipment
is turned off causing a discharge of 50 watt-seconds of energy or more through a 1500 ohms resistor
connected across its terminals, shall be fitted with circuitry to drain or remove this charge when the
equipment power is turned off.
5.1.18Stationary battery installation mounted on racks shall be fitted with earthquake bracings
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15 This grounding conductor run is form the main ground bar to the equipment rack lineup. This
conductor is normally made to run cable runways atop equipment rack lineup where individual
equipment rack and rack ground wires are bonded to.
16 For equipment racks, grounding conductors are fitted running the length of the rack to facilitate
neat individual equipment shelves grounding.
17 See No. 16
5.2 RADIO TRANSMITTING & RECEIVING SAFETY REQUIREMENTS
5.2.1 Fixed Station (Point-to-Point; Television, FM & AM, Radio; Space Communication)
This section covers radio transmitting and receiving stations at fixed locations used for point-to-point
overland or space communications and video, AM and FM transmission.
A. A fixed radio station building is not likely to be struck directly by lightning because of the
shielding effect provided by the antenna tower/s or support structures. However, waveguides, the
shield 2 of coaxial cables and high frequency antenna transmission lines can conduct hazardous
currents into the building unless adequate protective measures are employed. The station grounding
system is employed to divert as large a proportion of the surge current directly to earth before it enters
the building. The grounding system shall also be designed to reduce earth potential gradients in and
around the station building.
B.Radio site protection involves special consideration because direct lightning hits are usually
expected. The bonding, grounding and protection schemes shall have to be heavy duty and very
carefully engineered, installed and maintained in order to hold differences of potential between
various parts of the station to safety values. The installation shall be adequately grounded and
incoming overland communication and power lines fitted with special protection devices. The extentto which protection measures must be carried and their effectiveness is greatly affected by the earth
resistivity at the station location.
C. Equipment protection design is based on preventing voltage surges, beyond the voltage surge
limit of the equipment or parts thereof, from reaching that equipment or component. For solid state
component protection, low voltage protection devices have limited surge capability themselves,
several stages of protection may be employed.
D. Most electronic and communication equipment installations require A.C. power for certain
components. Commercial power lines, being susceptible to voltage and current surges due to
lightning and switching operations, shall necessitate protection considerations to prevent damage to
equipment connected to such lines.
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E. The earth electrode shall be any or a combination of made electrodes specified in rule 3.. C.
The ground resistance shall not be greater than 2.0 ohms at all times as measured by the fall of
potential method as specified in rule 3.4.1 B. Conductor size shall be no less than those specified in
Table 5-1. Aluminum, copper covered steel and other types of conductors may be used in place of the
copper conductor specified in Table 5-1 provided the current-carrying, corrosion-resisting
characteristics and insulation are equal to or better than the specification of the conductor beingreplaced. The minimum wire size specified in Table 5-1 is for electrical protection consideration only
if the system design calls for portions of the grounding system network to carry operating currents,
the conductor size shall be increased correspondingly.
5.2.2 Mobil e Station (Land mobile; Maritime mobile; Aeromobile)
This section covers radio transmitters, receiver, transceivers and allied equipment at mobile locations
such as:
1. radio installation on board vehicles, like automobiles, trucks, trains, etc. whose
movement or travel in confined overland.
2. radio installation on board water crafts like boats, ships, etc.
3.Aeromobile radio installations on board aircrafts and space crafts.
A. The counterpart base station of such mobile installations shall comply with safety provisions
provided under Rule 5.2.1
B. Installation of transceivers, handsets, control panels, microphones, loudspeakers, etc. shall not
increase the risk of injury of the driver or pilot and passengers in case of accident or collision.
C. Battery cables shall be fused as close to the battery terminals as practicable with fuse rating not
greater than 150% of the peak load current.
D. Battery cables shall have a current carrying capacity of not less than 250% of the peak load
current.
E. Battery cables shall have insulation strength rating of not less than 10 times the maximum
voltage to which it is to be connected and adequate mechanical strength to withstand the expected
abrasion; exposure to dirt, heat (150 C), humidity and the extreme environmental conditions mobile
installations encounter.
F. Battery or power wiring in aircraft installations shall be adequately fused in such manner that
current overloads due to equipment or wiring malfunction shall not affect other vital navigationequipment in the aircraft connected to the same battery or power supply.
G.Electronic and communication installations in larger water craft or trains are mostly powered
from normal A.C. supply and in such cases, rules in this Code to meet general rule 5.1.1 apply.
H.Cables to be used for watercraft installation shall be those approved for marine application.
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(Telephone, Telegraph, Telex etc.)
This section covers equipment installation employed for selective interconnection of channels of
communication using electro mechanical and/or electronic circuit elements to perform the function.
5.3.1Switching equipment is subject to damage from lightning and power fault currents which may be
conducted from outside plant cable or wire circuits. A.C. operated equipment can be damage from
lightning and switching surges conducted through the electric power lines. To protect personnel and
prevent damage to equipment these foreign potential surges shall be effectively limited by application of
suitable protective devices.
5.3.2 Surge arresters of suitable type and rating shall be connected on all wire circuits entering the
building except on wire lines meeting all of the following criteria:
1. The entire length is underground;
2. Not bunched with a circuit any portion of which is installed above ground level;
3. Not bridged to any wire circuit that may be exposed to foreign potential by contact or induction.
5.3.3 Depending on the desired protection level adopted, arresters should be fitted on power services
serving the station.
5.3.4The switching office earth electrode shall be any or a combination of made electrode specified in
Rule 3.2.4 C. The ground resistance shall be 5.0 ohms or less at all times as measured by the fall of
potential method.
5.3.5The earth electrode(s) provided under the rule 5.3.4 shall be bonded to the following (when present)
to form the switching office earth electrodes:
1. Continues buried metallic public water pipe system;
2. Continues buried metallic private water pipe system with at least 3.0 meters of buried pipe;
3. Deep well metal casing.
5.3.6 Connections to earth electrodes shall be made using methods and clamps acceptable to the entity
enforcing this CODE.
5.3.7For big offices, a ground bar shall be used, connected to the earth electrodes. The ground bar serves
as distribution or principal terminating point. For small offices the for ground may be omitted and
grounding conductor connected to the earth electrode on one end, free on the other end and running thefull length of the equipment line-up, where equipment rack/s shall be bonded.
5.3.8Ground conductor sizes, shall be in accordance with Table 5-1.
5.3.9 Insulation of all cables shall be polyvinyl-chloride (PVC) or equivalent formulation with equal or
better resistance to burning.
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5.3.10 Office furnitures required in the operations should be of metal construction or other non-
combustible material contents.
5.3.11 Stationary and other office and maintenance supply shall be stored in areas external to the
switching rooms. It shall be prohibited to store combustible materials in transformer vaults, switch gear
rooms and power distribution.
5.4 COMPUTER AND DATA SAFETY REQUIREMENTS
This section covers the minimum safety requirements in Electronic Data Processing Center
installations. Values, in terms of direct monitary cost, as a result of expensive components and in terms of
operational service continuity, tend to be extremely high and expensive damage to these installations can
have catastrophic consequences.
5.4.1The EDP equipment is AC operated and can be damaged by current surges conducted through the
electrical power line. To protect personnel and prevent damage to equipment, these foreign potential
surges shall be effectively limited by application of suitable protective devices.
The EDP Center earth electrodes shall be any or a combination of made electrodes specified in
rule 3.2.4 C and shall be engineered and installed in accordance with rules 5.3.4 through 5.3.8 of this
code.
5.4.2The Computer is the vital nerve center in any EDP installation and prevention of fire shall be the
overriding concern.
A. The computer shall be provided with physical separation or orientation to reduce or minimize
the effect of any detrimental external influences.
B. The facility shall be installed in a non-combustible housing structure. This shall include fire
and explosion-proof protection from the surroundings, such as firewalls, smoke detectors, water
proof ceilings, and floor covering materials of Vinyl tiles, high pressure plastic laminates, or other
non-combustible materials.
C. The large quantity of wiring associated with such installation and the mandatory requirements
for air-conditioning leads to concealed spaces either under the floor, in the walls, or in the ceiling.
Obviously, no combustible should be stored in these concealed spaces.
D. Power circuits and signal circuits shall be installed in separate conduits and raceways.\
E. The signal wiring shall be contained in cable structure with an over-all jacket or Polyvinyl
Chloride (PVC) or equivalent formulation with equal or better resistance to burning.
F. Office furnitures required in the EDP operations should be of metal construction or other