Overview Hazardous Locations Appletton.ppt

A Guide for use of Electrical Products in Hazardous Locations — © 20081

2008 Overview of Hazardous Locationsand the NEC®


Topics for Discussion

• NEC® Article 500 Code Sections • Review of Class, Division, and

Groups• Standards Organizations• Why Articles 505 & 506 Were

Added to the NEC®

• Review Zone System• Design of Explosionproof

Equipment• Hazardous Location Lighting• 2008 NEC® Overview• Interpretation of the 2008 NEC®

Changes• Review EGS Product Offering


NEC® Article 500 Code Sections

• Article 500 Hazardous (Classified) Locations• Article 501 Class I Locations• Article 502 Class II Locations • Article 503 Class III Locations• Article 504 Intrinsically Safe Systems• Article 505 Class I, Zone 0, 1, and 2 Locations• Article 506 Class II, Zone 20, 21, and 22 Locations• Article 510 Hazardous (Classified) Locations -

Specific • Article 511 Commercial Garages, Repair and

Storage• Article 513 Aircraft Hangars• Article 514 Motor Fuel Dispensing Facilities • Article 515 Bulk Storage Plants• Article 516 Spray Application, Dipping, and Coating

Processes


Class Locations

• Class I - Gases & Vapors

• Class II - Dusts

• Class III - Fibers & Flyings


Class I Locations (Gases)

• NEC® Article 500.5(B) – An area where FLAMMABLE

GASES, FLAMMABLE LIQUID-PRODUCED VAPORS, OR COMBUSTIBLE LIQUID-PRODUCED VAPORS are or may be present in the air in sufficient quantities to produce explosive or ignitible mixtures.


Class I Locations (Gases)

• Class I Industries & Applications– Natural or liquefied gas storage

facilities– Chemical plants– Petroleum refineries– Bulk handling or storage facilities for

gasoline– Dip tanks– Storage tanks for flammable liquids

or gas– Spraying areas for paints or plastics– Aircraft fuel servicing areas or

hangers– Well drilling (oil and gas), offshore or

on– Pipeline pumping areas– Printing machine areas


Class II Locations (Dust)

• NEC® Article 500.5(C)– Locations that are hazardous

because of the presence of combustible dust.

– Shall include those specified in 500.5(C)(1) and (C)(2).


Class II Locations (Dust)

• Class II Industries and Applications

– Grain storage, handling or processing plants

– Coal storage, handling or processing facilities

– Metal grinding or metal powder producing facilities

– Gunpowder or explosive (fireworks) plants

– Sugar, cocoa, spice or starch production or handling facilities


Class III Locations (Fibers)

• NEC® Article 500.5(D) – An area made hazardous because of

the presence of easily ignitible fibers or flyings, but in which such fibers or flyings are not likely to be in suspension in the air in quantities sufficient to produce ignitible mixtures.

– Shall include those specified in 500.5(D)(1) and (D)(2).


Class III Locations (Fibers)

• Class III Industries and Applications

– Cotton, textile or flax producing or handling facilities

– Wood cutting, pulverizing or shaping plants

– Clothing manufacturing facilities


Conditions

• Division 1

• Division 2


Division 1 Location

• NEC® Articles 500.5(B)(1), 500.5(C)(1) and 500.5(D)(1)

– An area where the hazard exists under normal operation conditions

– This also includes locations where the hazard is caused by frequent maintenance or repair work or frequent equipment failure


Division 2 Location

• NEC® Articles 500.5(B)(2), 500.5(C)(2), and 500.5(D)(2)

– An area where ignitible gases, vapors, dust, or fibers are handled, processed, or used, but which exist only under abnormal conditions, such as containers or closed systems from which they can only escape through accidental rupture or breakdown

• Note: No electrically conductive dust are included in Class II, Division 2 atmospheres


Comparison of Division 1 and Division 2 for Gases


Groups A, B, C, and D (Gases)

• NEC® Article 500.6(A) – Groups indicates the degree of the

hazard

– Groups A, B, C & D are classified by chemical families as shown in NFPA 497-2004 and 325M-1991

– An important factor in classifying a gas or vapor by Group is how much pressure is created during an explosion. Group A (Acetylene) creates the most pressure, with Group B (Hydrogen) next

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

Group AAcetylene

Group BHydrogen

Group CEthylene

Group DPropane


Dust Groups E, F and G

• NEC® Article 500.6(B)– Groups indicates the degree of the

hazard, based on Electrical Resistivity from Table on right (Source: ANSI/ISA-12.10-1988)

– Group E (Electrically Conductive) – Atmospheres containing combustible metal dust

– Group F (Fuel) – Atmospheres containing Carbon Black, Charcoal, Coal, or Coke Dust

– Group G (Grain) – Atmospheres containing agricultural and other dusts


Summary of Class I Locations

• Class I Locations– Class I locations are those in which flammable gases, flammable liquid–produced vapors, or

combustible liquid–produced vapors are or may be present in the air in quantities sufficient to produce explosive or ignitible mixtures

• Class I, Division 1– There is or may be an explosive atmosphere of gases or vapors mixed with air present during

normal operation, for any reason

• Class I, Division 2– There is an explosive atmosphere of gases or vapors mixed with air when an abnormal condition

exists, such as failure of a containment wall or ventilation system

• Class I, Groups– Group A. Acetylene. – Group B. Flammable gas, flammable liquid–produced vapor, or combustible liquid–produced vapor

mixed with air that may burn or explode, having either a maximum experimental safe gap (MESG) value less than or equal to 0.45 mm or a minimum igniting current ratio (MIC ratio) less than or equal to 0.40; hydrogen

– Group C. Flammable gas, flammable liquid–produced vapor, or combustible liquid–produced vapor mixed with air that may burn or explode, having either a maximum experimental safe gap (MESG) value greater than 0.45 mm and less than or equal to 0.75 mm, or a minimum igniting current ratio (MIC ratio) greater than 0.40 and less than or equal to 0.80; ethylene

– Group D. Flammable gas, flammable liquid–produced vapor, or combustible liquid–produced vapor mixed with air that may burn or explode, having either a maximum experimental safe gap (MESG) value greater than 0.75 mm or a minimum igniting current ratio (MIC ratio) greater than 0.80; propane


Summary of Class II Locations

• Class II Locations– There is the presence of combustible dust

• Class II, Division 1– Combustible dust is in the air under normal operating conditions in quantities sufficient to produce explosive or ignitible

mixtures– Mechanical failure or abnormal operation of machinery or equipment might cause such explosive or ignitible mixtures to

be produced, and might also provide a source of ignition through simultaneous failure of electrical equipment, through operation of protection devices, or from other causes

– Group E combustible dusts may be present in quantities sufficient to be hazardous

• Class II, Division 2– Combustible dust due to abnormal operations may be present in the air in quantities sufficient to produce explosive or

ignitible mixtures– Combustible dust accumulations are present but are normally insufficient to interfere with the normal operation of

electrical equipment or other apparatus, but could as a result of infrequent malfunctioning of handling or processing equipment become suspended in the air

– Combustible dust accumulations on, in, or in the vicinity of the electrical equipment could be sufficient to interfere with the safe dissipation of heat from electrical equipment, or could be ignitible by abnormal operation or failure of electrical equipment

• Class II, Groups– Group E. Atmospheres containing combustible metal dusts, including aluminum, magnesium, and their commercial

alloys, or other combustible dusts whose particle size, abrasiveness, and conductivity present similar hazards in the use of electrical equipment; metal dusts

– Group F. Atmospheres containing combustible carbonaceous dusts that have more than 8 percent total entrapped volatiles or that have been sensitized by other materials so that they present an explosion hazard; coal, carbon black, charcoal, coke dusts

– Group G. Atmospheres containing combustible dusts not included in Group E or F, including flour, grain, wood, plastic, and chemicals


Summary of Class III Locations

• Class III Locations– Those that are hazardous because of the presence of easily ignitible fibers

or materials producing combustible flyings are handled, manufactured, or used, but in which such fibers/flyings are not likely to be in suspension in the air in quantities sufficient to produce ignitible mixtures

• Class III, Division 1– Easily ignitible fibers/flyings are handled, manufactured, or used

• Class III, Division 2– Easily ignitible fibers/flyings are stored or handled other than in the

process of manufacture


Standards Organizations

• AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI) – Does not develop standards per se, but acts as a clearing house for information on

national and international standards writing groups to prevent duplication of effort• AMERICAN PETROLEUM INSTITUTE (API)

– Publishes Recommended Practice for Classification of Locations for Electrical Installations in Petroleum Facilities (API RP 500)

• CANADIAN STANDARDS ASSOCIATION (CSA)– Established standards similar to UL for the testing of electrical products

• ELECTRICAL TESTING LABORATORIES (ETL)– Provides a listing, labeling and follow-up service for safety and sanitation

certification of electrical and gas/oil fueled products to nationally recognized safety standards or specifically designated requirements of jurisdictional authorities

• FACTORY MUTUAL (FM)– Non-profit third party testing and certification organization, providing many of the

same services as UL• INTERNATIONAL ELECTROTECHNICAL COMMISSION (IEC)

– Comprised of approximately forty member countries, including the United States. The purpose of the IEC is to establish standards for a wide variety of electrical products to encourage international trade. IEC publication 79, entitled Electrical Apparatus for Explosive Gas Atmospheres, consists of several parts covering area classification, test apparatus and several techniques used for protection of apparatus, intended for use in hazardous locations

• INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS (IEEE)– Publishes publications which provide thorough analysis of system considerations

and guidance on the design and maintenance of electrical systems and equipment• INSTRUMENTATION SYSTEMS AND AUTOMATION SOCIETY (ISA)

– Develops standards; certifies industry professionals; provides education and training; and publishes books and technical articles

• LOCAL BUILDING CODES– These codes influence and determine ultimate decisions on product suitability

• MANUFACTURERS DATA– Manufacturers working with recognized organizations, develop and improve

products for third party certification and thus set additional product suitability standards

– Standards set by such organizations identify the criteria used by manufactures in the design and company testing of its products

• NATIONAL FIRE PROTECTION ASSOCIATION (NFPA)– Set standards for the wiring and control of electricity. NFPA is composed of national

and regional groups, plus individuals, firms and institutions interested in protecting life and property. This organization sets minimum standards to form a National Electrical Code (NEC®), which is used as a criteria for insurance, state and civic inspectors when making inspections or recommendations for electrical installations

• NORTH AMERICAN CERTIFICATION– The United States and Canada are both members of the IECEx Conformity

Assessment Scheme. As a result for Hazardous Location Certification UL and CSA accepts each others data for purpose of providing their National Certification Marks

• NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION (NEMA)– Issues standards on electrical equipment on all major categories of electrical

equipment. Generally where construction and performance relate to safety, reference is made to standards of others, such as Underwriters Laboratories Incorporated

• OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION (OSHA)– Mandates the use of electrical equipment that has been verified by third parties as

being suitable for the application. Some units of a system installation are not necessarily third party certified if such certification is judged not applicable

• OTHER ASSOCIATIONS– Professional and technical organizations develop and/or sponsor standards as

product guidelines, application recommendations, safety rules or test methods• UNDERWRITERS LABORATORIES, INC. (UL)

– There are over a dozen UL Published Standards that govern the design and company testing of electrical products. In addition to specific UL Standards, UL publishes three books containing the names of companies who have qualified to use the Listing or Classification Marking of Underwriters Laboratories on products which have been found to be in compliance with applicable UL requirements. These three publications can be used to obtain the names of companies who have a Listing in a specific product category, and to obtain information regarding the scope, limitations, or special conditions of a particular product category


Why Were Articles 505 & 506Added to the NEC®?

• To promote harmonization with international standards so that multi- national companies can globalize their standards for facilities constructed both inside and outside North America, thereby allowing a single set of standards to be utilized anywhere in the world

• In many instance the respective country’s National Standards contain national differences from the base IEC Standards


Article 505: Zone 0 Hazardous Locations

• Zone 0 covers areas in which an explosive gas atmosphere is present continuously or for long periods (> 1000 hrs/yr.)

– This usually applies to the inside vapor space of containers, process vessels or tanks

• Intrinsic Safety (Ex i) is the only method of protection permitted in Zone 0

– Used for industrial instrumentation & control



• Zone 1 covers areas, in which an explosive gas atmosphere can be expected to be present intermittently (between 10 and 1000 hrs/yr.)



• Zone 2 covers areas, in which an explosive gas atmosphere can only be expected under abnormal conditions (between 0.1 and 10 hrs/yr.)


Article 505: Zone 0, 1, 2 Hazardous Locations

Zone 0

Zone 1

Zone 2

Non-Hazardous Zone


Group Classification NEC® Article 505

• Group IIC. Atmospheres containing acetylene, hydrogen, or gases or vapors of equivalent hazard

– This grouping is equivalent to NEC Class I, Groups A and B, as described in Sections 500.6(A)(1,2)

• Group IIB. Atmospheres containing acetaldehyde, ethylene, or gases or vapors of equivalent hazard

– This grouping is equivalent to NEC Class I, Group C, as described in Section 500.6(A)(3)

• Group IIA. Atmospheres containing acetone, ammonia, ethyl alcohol, gasoline, methane, propane, or gases or vapors of equivalent hazard

– This grouping is equivalent to NEC Class I, Group D, as described in Section 500.6(A)(4)



• Zone 20 covers areas which ignitible concentrations of combustible dust or ignitible fibers/flyings are present continuously or for long periods of time

– This usually applies to the inside of containment systems



• Zone 21 covers areas which ignitible concentrations of combustible dust or ignitible fibers/flyings are likely to exist occasionally under normal operating conditions, frequently because of repair or maintenance operations or because of leakage

• Where equipment is operated or processes are carried on that could result in the release of ignitible concentrations of combustible dust or c fibers/flyings or cause simultaneous failure of electrical equipment that can become a source of ignition

• Can be adjacent to a Zone 20 location where effective safeguards against ventilation failure are not provided

– This usually applies to the area outside of containment systems



• Zone 22 covers areas which ignitible concentrations of combustible dust or ignitible fibers/flyings are not likely to occur in normal operation, or for a short period

• Where combustible dust or fibers/flyings are handled, processed, or used but normally confined within closed containers of closed systems

• Can be adjacent to a Zone 21 location where effective safeguards against ventilation failure are not provided

– This usually applies locations where controllable dust layers are formed that are likely to be raised into explosive dust–air mixtures


Article 506: Zone 20, 21, 22 Hazardous Locations

Zone 20

Zone 21

Zone 22

Non-Hazardous Zone


IEC Protection Techniques for Hazardous Areas

• Flameproof “d”– Zone 1

• Contain internal explosion• Control external temperature of enclosure• Similar to NEC® explosionproof• Usually cast enclosure• Typical use in luminaires and motor starters

• Increased Safety “e”– Zone 1

• High impact resistant enclosures—FRP, GRP, sheet steel/aluminum, stainless steel

• Enclosure will not hold static charge• Maintain minimum of IP 54 ingress protection• Apparatus non arcing/sparking• Typical use in terminal enclosures

• Flameproof Plus Increased Safety “de”– Zone 1

• Location of arcing has “d” protection (flameproof)• Connection terminals have “e” protection (increased safety)• Typical use in switches, luminaires , controls, plugs and

receptacles/sockets – Items such as power outlets, switches, some

luminaires , etc., cannot be protected by “e” mode only. In this case “d” and “e” are combined

• Intrinsic Safety “ia” and “ib”– ia Zone 0 & 1– ib Zone 1

• Incapable of releasing enough energy to cause an explosion• Typical use in communication equipment

• Encapsulation “m”– m Zone 1– ma Zone 0– mb Zone 1

• Epoxy or other resin to totally seal arcing and sparking devices• Typical use in luminaires controls and sealed switches

• Non-Sparking “n”– Zone 2

• Enclosure restricts ingress of hazardous gases• nA=non sparking construction• nR=restricted breathing• nC=hermetically sealed, non incentive• Typical use in luminaires

• Oil Immersion “o”– Zone 1

• Oil totally seals arcing and sparking devices• Typical use in hazardous rated transformers and switches

• Pressurization “p”– px Zone 1– py Zone 1– pz Zone 2

• Expels ignitible vapor/gas• Maintains positive enclosure pressure

• Powder Filled “q”– Zone 1

• Finely ground powder to totally seal arcing and sparking devices• Typical use in luminaires, controls and sealed switches


IEC Protection Techniques for Areas with Combustible Dusts

• Intrinsic Safety “iD”– iaD for use in Zone 20, 21, 22– iaD for use in Zone 21, 22– (Ex ibD) associated electrical apparatus - installation in

the safe areas• Incapable of releasing enough energy to cause an

explosion

• Typical use in communication equipment

• Encapsulation “mD”– maD for use in Zone 20, 21, 22– mbD for use in Zone 21, 22

• Epoxy or other resin to totally seal arcing and sparking devices

• Typical use in luminaires, controls and sealed switches

• Pressurization “pD”– Zone 21, 22

• Expels ignitible vapor/gas• Maintains positive enclosure pressure

• Protection by Enclosures “tD”– tD A21 Procedure A for Zone 21– tD B21 Procedure B for Zone 21

• High impact resistant enclosures—FRP, GRP, sheet steel/aluminum, stainless steel

• Enclosure will not hold static charge• Maintain minimum of IP 54 ingress protection• Apparatus non arcing/sparking• Typical use in terminal enclosures


NEMA Classified Location Enclosures

• Type 7 – For indoor use in hazardous (classified) locations as Class I, Division 1,

Groups A, B, C, or D

• Type 8 – For indoor or outdoor use in hazardous (classified) locations as Class I,

Division 1, Groups A, B, C, or D

• Type 9 – Intended for indoor use in hazardous (classified) locations as Class II,

Division 1, Groups E, F, and G

• Type 10 (MSHA)– Shall be capable of meeting the requirements of the Mine Safety and Health

Administration, 30 C.F.R., Part 18

• Note: There are no provisions in NEMA types for Class III locations. However, Type 9 would be suitable


Explosion Elements

• Fuel– Flammable Gas Vapors

– Combustible Dusts

– Flyings or Fibers

• Oxygen– Air

– Other Oxidizing Atmospheres

• Ignition– Arc

– Spark

– Heat Generated by Equipment


UL Explosionproof Apparatus Definition

• Class I, Division 1 – An enclosure that will withstand an internal explosion of gases or vapors and prevent

those gases or vapors from igniting gases or vapors in the surrounding atmosphere outside of the enclosure


Explosionproof Enclosure Design

• An explosionproof enclosure must be able to:

– Withstand the internal explosion pressure

– Prevent propagation of flame through any joint or opening to the outside of the enclosure

– Maintain a low external temperature that will not ignite the surrounding flammable atmosphere

• U.L. explosionproof test (U.L. 1203)

– Explosion test are performed to determine the maximum pressure and propagation effect

– Hydrostatic pressure test at four times the highest explosion pressure


Explosionproof Equipment - Joints

• Enclosure joint designs prevent the propagation of flame, the most common types are:

– Ground (Flat) Joint Construction

– Threaded Joint Construction

– Labyrinth-Path Construction

– Precision Acme / Conical Thread Construction

– Close Tolerance Shaft Construction

– Interlocking Concentric Ring Construction



• Ground (Flat) Joint Construction



• Threaded Joint



• Labyrinth Path



• Close Tolerance Shaft


Conduit Seal Fittings

• Required within 18 inches of an enclosure containing arcing or high temperature device. (Class I, Division 1 & 2 locations)

• Required in Class I, Division 1 locations where 2 inch or larger conduit enters enclosures that house terminals, splices, or taps

• Required at Class I boundary where conduit leaves the hazardous area

• U.L. requires that sealing compound/cement is certified/ approved for use with the specified sealing fitting

• Depth of sealing compound should be equal to trade size of conduit, having minimum thickness of 5/8 in



• Limit communication of gas in electrical systems

• Minimize pressure piling


Conduit Seal Function and Application

• The function of a conduit seal is to prevent the passage of gases, vapors or flames from one portion of a conduit system to another

• They also restrict large amounts of ignitible gases or vapors from accumulating to confine explosive pressure

• Per the 2008 NEC, Conduit seals shall be located in accordance with article 501.15 (A)(1) through (A)(4)

– Entering Enclosures – containing arcing, sparking or heat producing components

– Where a trade size 2” or larger conduit enters an enclosure containing terminals, splices or taps

– Two or more explosion proof enclosures – Class I Division 1 Boundary– Pressurized enclosures - In each conduit

entry that is NOT pressurized as part of the protection system



• Standard conduit seal fittings are limited to 25% fill

• Expanded fill conduit seal fittings can be used with a conduit system allowing up to 40% conduit fill


3 Installation Methods Used Throughout the World


Lighting Product Nameplate with UL Listing

• Catalog Number• Third Party Certification (UL Listing

Mark)• Hazardous Location Suitability

– Class I Division 2 “T” Rating– Class II Group E,F,G “T” Rating– Class III

• Electrical Data– Lamp Information– Primary voltage– Operating Amperage– Power Factor (90% Minimum)– Hertz Rating (50 or 60)– Supply Wire


Hazardous Lighting – “T” Rating

• Every hazardous atmosphere has a temperature that, if exceeded, will cause the flammable or combustible to ignite. Accordingly, this temperature, called the “T” rating, is a critical safety benchmark. Hazardous location luminaires must run cooler than the ignition temperature of the surrounding atmosphere

• Per the “T” rating chart, T1 rated luminaries can only be used in locations where the atmosphere needed a temperature greater that 450° C to ignite. Conversely, T6 rated luminaires run the coolest and can be used in very volatile environments where temperatures can not exceed 85° C

• The “T” rating for a fixture is the temperature of the hottest spot on or in the luminaire depending on the luminaires’ Class or Zone rating. Whether the “T” rating is recorded on or in the luminaire depends on whether it is an enclosed & gasketed, explosionproof, flameproof, or restricted breathing fixture

Hazardous Lighting - “T” Rating

Degree C ID #

351-450 T1

326-350 350

301-325 352

281-300 T2

261-280 T2A

231-260 T2B

216-230 T2C

201-215 T2D

181-200 T3

166-180 T3A

161-165 T3B

136-160 T3C

121-135 T1

101-120 T4

86-100 T5

85 T6


Enclosed & Gasketed “T” Ratings

• Enclosed & gasketed fixtures measure their “T” ratings on the inside. If a hazard is accidentally released into the atmosphere and reaches inside the fixture, it will not ignite assuming the fixture’s “T” rating is below that of the hazard


Explosionproof, Flameproof & Restricted Breathing “T” Ratings

• For explosionproof and flameproof fixtures, the “T” ratings are measured on the exterior of the fixture. This is due to the explosionproof and flameproof fixture’s ability to disarm any explosion caused within the interior of the fixture. Therefore, the exterior temperature of the fixture becomes the forerunning concern

• Restricted breathing fixture construction is similar to enclosed & gasketed but requires a seal to give the product the “restricted breathing” rating. This allows restricted breathing fixtures to have their “T” ratings measured from the surface of the fixture


Guidelines for Luminaire Use in Zone 2 Locations

Authority LocationMethod of Protection

T number measurement

made at

Sealed cable and/or conduit/optic required

NEC Zone 2 or Division 2 UL844 Division 2 Lamp hot spotCable- yesConduit- no

NEC

Zone 2

Restricted breathing (AEx nR) Externally at hot spot

on surface

Optic- yesCable- yes

Conduit- yesIECRestricted breathing

(Ex nR)


Comparison of NEC® and IEC Luminaire Construction

• “T” Code Measurement Points– 1984 – Class I, Div. 2 Conventional

NEC fixture • Hot Spot on LAMP

– 2000 – Entry to Zone System – Class I, Zone 2 Ex nR (Restricted Breathing)

• Hot Spot on Globe• Seal Required on Entry

– 2004 – Optimized Class I, Zone 2 AEx nA nR

• Hot Spot on Globe/Ballast Compartment

• Factory Sealed, no entry seals required


Comparison of NEC® and IEC Luminaire Construction

• Restricted Breathing

• Advantages– Higher wattage fixture can be

utilized and still comply w/ codes

• Disadvantages– Cracked or loose globe renders

product unsafe

– Likelihood of retrofit using unapproved components

– Costs more than conventional fixture


2008 National Electrical Code

• The objective of Articles 500 - 516 of the NEC® is to insure that hazardous location occupancies are properly identified and evaluated, and to make sure that electrical equipment and wiring installed and used in hazardous locations does not become an ignition source for an explosive atmosphere. This is accomplished by:

– Defining and classifying the forms and types of flammable materials that may be present– Requiring that hazardous (classified) locations be assessed, formally classified and documented for the

degree and type of hazard that they represent– Recognizing different hazardous location and flammable atmosphere classification systems, and specifying

how they might coexist in the same installation– Defining and recognizing explosion protection techniques for electrical equipment that are matched to the

particular hazardous atmosphere(s) that may be present– Specifying electrical equipment marking and other certification documentation that must be provided by

manufacturers of hazardous location electrical equipment to installers, users and inspectors– Providing specialized installation requirements for specific hazardous location protection techniques or

occupancies– Providing references to standards and publications from NFPA® and other recognized organizations where

users and inspectors can obtain more information– Where necessary, requiring that specification and installation of electrical equipment in hazardous locations

be done under the direction of specially qualified individuals


Interpretation of the 2008 NEC®

• The following Article sections have been revised during the 2008 NEC® Code cycle

– These changes are those that are substantive and should be noted– These changes do not include those that are editorial in nature


Interpretation of Article 500:Hazardous (Classified) Locations, Classes I, II, and III, Divisions 1 and 2

• Section 500.1 and 500.5– Flammable liquid-produced vapors,

combustible liquid-produced vapors

• Section 500.7– Combustible gas detection equipment

• 500.1 and 500.5 adds the terms flammable liquid-produced vapors and combustible liquid-produced vapors to the list of materials that require analysis to determine of special electrical equipment or wiring is required to minimize the hazardous risks

• 500.7(K)(1); 500.7(K)(2); and 500.7(K)(3) now require that combustible gas detection equipment be listed for the appropriate gas group and for the detention of the specific gas or vapor to be encountered


Interpretation of Article 501: Class I Locations

• Section 501.10– Type PVC conduit and Type RTRC conduit

for Class I, Division 1 and Class I, Division 2 Areas

• Section 501.30– Flexible metal conduit and liquidtight

flexible metal conduit restriction as sole ground-fault current paths

• 501.10 permits listed PVC conduit and RTRC conduit where encased in a concrete envelope a minimum of 50 mm (2 in.) thick and provided with not less than 600 mm (24 in.) of cover measured from the top of the conduit to grade

• 501.30 requires that liquidtight flexible metal conduit, as well as flexible metal conduit, be installed with internal or external bonding jumpers in parallel with each conduit if these conduits are “to be relied upon to complete a sole equipment grounding path.” The equipment bonding jumpers must comply with all other requirements of Section 250.102


Interpretation of Article 502: Class II Locations

• Section 502.30(B)– Liquidtight flexible metal conduit restrictions as sole ground-

fault current path

• Section 502.120(B)– In Class II, Division 2 Areas – Coils and windings in tight metal

housings. Future requirements will be dusttight enclosures

• Section 502.130(B)– In Class II, Division 2 Areas – Fixed lighting provided with

dusttight enclosures

• Section 502.150(B)– In Class II, Division 2 Areas – Contacts in tight-fitting

enclosures. Future requirements will be dusttight enclosures

• 502.30 is similar to the change in 501.30(B), this section has been rewritten to clarify that in Class III, Division 1 and 2 locations, liquidtight flexible metal conduit is not permitted to be used as equipment grounding conductor without an additional bonding jumper installed

• 502.120(B) states where not located in the same enclosure with switching mechanisms, control transformers, solenoids, and impedance coils shall be provided with tight metal housings without ventilating openings or shall be installed in dusttight enclosures

• 502.130(B) now specifically requires a rating of “dusttight” for the fixed lighting enclosure (ballast tank)

• 502.150(B) requires that for Class II, Division 2 locations, the enclosures must have tight fitting covers, with no openings through which sparks or burning material might escape, to minimize the entrance of dust or be dusttight. Nonincendive circuits may be contained in general purpose type enclosures. Resistors must have enclosures identified for Class II, Division 1


Interpretation of Article 503: Class III Locations

• Section 503.30(B)– Liquidtight flexible metal conduit

restriction as sole ground-fault current path

• Similar to the change in 501.30, this section has been rewritten to clarify that in Class III, Division 1 and 2 locations, liquidtight flexible metal conduit is not permitted to be used as equipment grounding conductor without an additional bonding jumper installed


Interpretation of Article 504: Intrinsically Safe Systems

• Section 504.2– Definition for Simple Apparatus

• Section 504.70– Sealing conduits and cables to be

identified for the purpose

• 504.2 places any limitations on the use of simple apparatus that can be used in the hazardous location will be listed on the control drawing for the associated apparatus. In the case of using a device that will heat up, such as an RTD, care must be taken to stay below the 1.3 Watt limit to avoid creating a hot surface. Care must also be taken that the use of simple apparatus does not connect two or more intrinsically safe circuits together in the hazardous location. This can create a situation where sufficient energy could be released to cause an ignition

• 504.70 requirements for conduit and cable seals containing intrinsically safe wiring were clarified. Though they are not required to be explosionproof or flameproof, they shall be accessible and identified for the purpose of minimizing passage of gases, vapors or dusts under normal operating conditions. References to Articles 502, 505, 506 which cover where explosionproof or flameproof seals are not required have been included in the section


Interpretation of Article 505: Class I, Zone 0, 1, and 2 Locations

• Section 505.7– Implementation of the Zone Classification System

• Section 505.8– Addition of Encapsulation Methods “ma” and “mb”

• Section 505.8– Combustible gas detection equipment

• Section 505.9(F)– Fiber Optic Cable Assemblies

• Section 505.15(C)– RTRC conduit and cable Schedule 80 PVC conduit for

Class I, Zone 2 Areas

• Section 505.25(B)– Flexible metal conduit and liquidtight flexible metal

conduit restrictions as sole ground-fault current path

• 505.7 removed the rule requiring that the classification of areas and the selection of equipment and wiring methods be the sole authority of a registered professional engineer. The new language requires that the total process of implementation of the Zone Classification System be conducted by qualified persons

• 505.8 added additional methods of protection technique that shall be permitted for equipment in Class I, Zone 0, Zone 1, or Zone 2 locations

– Encapsulation “ma”– Encapsulation “mb”

• 505.9(F) was added to address the proper wiring methods and sealing requirements for fiber optic cable assemblies installed in a Class I, Zone rated area

• 505.15(C) was added to permit RTRC conduit and Schedule 80 PVC conduit in Class I, Zone 2 areas of industrial establishments and where additional corrosion resistance is required

• 505.25(B) is similar to the change in 501.30(B), this section has been rewritten to clarify that in Class III, Division 1 and 2 locations, flexible metal conduit and liquidtight flexible metal conduit is not permitted to be used as equipment grounding conductor without an additional bonding jumper installed


Interpretation of Article 506: Zone 20, 21, and 22 Locations for Combustible Dusts or ignitible Fibers/Flyings

• Section 506.8– Several Protection Techniques added to the

article

• Section 506.9(F)– Fiber optic cable assemblies

• Section 506.25(B)– Liquidtight flexible metal conduit restriction

as sole ground-fault current path

• 506.8 added – Encapsulation “maD”– Encapsulation “mbD”– Protection by Enclosure “tD”– Protection by Pressurization “pD”– Protection by Intrinsic Safety “iD”

• 506.9(F) Where a fiber optic cable assembly contains conductors that are capable of carrying current, the fiber optic cable assembly shall be installed in accordance with 506.15 and 506.16, as applicable

• 506.25 Liquidtight flexible metal conduit shall not be used as the sole ground-fault current path. Where equipment bonding jumpers are installed, they shall comply with 250.102


Interpretation of Article 510: Hazardous (Classified) Locations – Specific

• There were no changes to Article 510 for the 2008 NEC®

• This is a general Article that defines the structure of the specific locations addressed in Articles 511 through 516


Interpretation of Article 511: Commercial Garages, Repair and Storage

• Section 511.2– Definitions for major and minor

repair garages were added

• Section 511.3– Area classification general

requirements

• 511.2 redefined major repair garage and minor repair garage

• 511.3(A) and 511.3(B) have been rearranged to clarify the new definitions


Interpretation of Article 513: Aircraft Hangers

• Section 513.2– Definition for aircraft painting

hanger

• Section 513.3– Aircraft painting hanger

classification requirements

• 513.2 defined the term aircraft painting hanger

• 513.2 was expanded to include the area classification requirements specific to the new aircraft painting hanger


Interpretation of Article 514: Motor Fuel Dispensing Facilities

• There were no significant changes made to Article 514 for the 2008 NEC®


Interpretation of Article 515: Bulk storage plants

• Section 515.7(A)– Schedule 80 PVC and RTRC Conduit

• RTRC was added as a permissible wire method above Class I locations


Interpretation of Article 516: Spray Application, Dipping, and Coating Processes

• There were no significant changes made to Article 516 for the 2008 NEC®


We provide the products…


Conduit and Cable Fittings

• Connect Cable to an electrical enclosure• Connect conduit to an electrical enclosure• Couple conduit• Accommodate changes in direction in

conduit system• Reduce or enlarge conduit• Prevent abrasion of wire insulation at

transition points throughout wiring system• Ensure continuity of ground• Attach conduit to a structure• Provide a seal against water, dirt, dust, oil• Relieve strain on conductors

(cord grips, cable supports)• Act as an extension of the mechanical

protection provided by the wiring system.


Conduit Outlet Boxes

• Some function as fittings

• Provide opening for splices

• Serve as a pulling fitting

• Permit access to wiring for maintenance


Plugs and Receptacles

• Provide power to portable / fixed equipment

– Motors

– Pumps

– Welders

– Compressors

• May be interlocked with switches


Lighting Fixtures

• Provides illumination in areas designated as classified or explosionproof

• Suitable for indoor or outdoor use where hazardous, damp and corrosive conditions exist

• UL listings as approved for use in specific classified areas

• Models available for Class I, Div. 1; Class II, Div. 1; UL 844; UL 1598A; Marine Type Electric Fixtures Outside Type (Salt Water); and paint spray booths


Cord & Cable Reels

• Continuous retractable power supply to moving machines (cranes, trains, hoists, etc)

• Can be sold with hand lamps

• Takes up slack as equipment moves


Control Stations & Panels

• Push buttons

• Selector switches

• Pilot lights

• Meters

• Windows

• ATEX Certified


Enclosures & Controls

• Disconnect Switches – load disconnect

• Motor Starters – disconnect means, circuit protection, undervoltage protection

• Circuit Breaker – protection for a given device

• Large Junction Boxes – cast enclosure for electrical connection


Enclosures & Controls

• Panelboards – protection for multiple circuits

• Switch Racks – factory assembled control center


EGS Brands with Hazardous Products

• Appleton• Curlee• O-Z/Gedney• A.T.X.• Nelson


Disclaimer

• The information presented in this presentation has been assembled from various sources. Although every attempt has been made to ensure accuracy, neither EGS Electrical Group/Appleton Electric LLC nor its contributors to this publication assumes responsibility for any inaccuracies or omissions in the data presented

• As a safety precaution, information to be utilized from this presentation should be verified from the National Electrical Code® and other sources

Documents

Overview Hazardous Locations Appletton.ppt