Allen Bradley Guide Switchgear-controlgear Assembly

8/10/2019 Allen Bradley Guide Switchgear-controlgear Assembly

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The easy way to build

switchgear and controlgear

assemblies in compliance with the regulations

A guide for partially type-tested switchgear andcontrolgear assemblies in compliance with EN 60 439


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What are the requirements?

My name is Rocky, and Im

looking forward to showing

you the way through these

guidelines.

Contents Page

EN 60 439 is recognised as the

established engineering practice for

switchgear and controlgear assemblies 3

What are the bases of

the agencies requirements? 4

Which control systems and

installations are subject to EN 60 439? 5

What is considered as a low-voltage

switchgear and controlgear assembly -

(ASSEMBLY) under EN 60 439? 6

What is the difference between

a TTA and a PTTA? 6

What does EN 60 439 define? 8

Directives for the utilisation of other

components as those applied for the

type-test of a TTA permit a range of freedom 10

Type-tested components simplify work 10

The added value performed by the ASSEMBLY

maufacturer requires safety verification 11

Calculation software simplifies verification

of the temperature rise 12

Special care with short-circuit

currents above 10 kA 12

Which tests must be performed on PTTA? 13

How can the expense for the technical

verification of PTTA be minimised? 13

Important notes regarding national

differences 13

Compilation of verifications and tests

of TTA and PTTA 14

A Manufacturers

Declaration, a Type-testing

Report and Routine Test

Protocol are required as asafety verification.

2


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4

What are the bases of the agencies

requirements?

The requirements are based upon the Low-voltage

Directive 73/23/EEC and the EMC Directive

89/336/EEC of the EU, as well as on their supple-

mentation by Directive 93/68/EEC, which concerns

the CE-marking.

In its fundamental requirements, the Low-voltage

Directive postulates the protection of persons, ani-

mals and property from the hazards and damage

which may result from electrical apparatus.

The EMC Directive states in Article 4:

The apparatus referred to in Article 2 shall be

so constructed that:

a) the electromagnetic disturbance it generates

does not exceed a level allowing radio and

telecommunication equipment and other

apparatus to operate as intended;

b) the apparatus has an adequate level of

intrinsic immunity of electromagnetic distur-

bance to enable it to operate as intended.

......

The central focus is on the pro-

tection of persons, animals andproperty as well as operation in

the intended manner without

malfunctions.


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Which control systems and

installations are subject to EN 60 439?

The standard cites (Subparagraph 1.1)

- stationary or movable assemblies,

- with or without enclosure,

- for use in connection with generation, transmis-

sion, distribution and conversion of electric

energy and for the control of electrical energy

consuming equipment.

EN 60 439 does not apply to individual devices for

which valid standards exist (motor starters in com-

pliance with IEC 947, for instance).

It follows from this that all electrical controls, distri-

bution boards and switchgear and controlgear

assemblies fall under EN 60 439.

It may not be concluded that EN 60 439 is the sole

standard to be applied. In the case of machine con-

trols, for instance, additional requirements in com-

pliance with EN 60 204 (Electrical Equipment ofMachines) must be fulfilled.

The EU Directives for low-voltage devices

(73/23/EEC) and for Electromagnetic Compatibility

(89/336/EEC) are valid in all countries of the

European Union (EU) and of the European Economic

Area (EEA) and in Switzerland (Ordinance on elec-

trical low-voltage equipment and Ordinance on

electromagnetic compatibility). Similar rules

which are based to a great extent on the directives

of the EU are valid or will soon be introduced in

other countries, such as the Commonwealth of

Independent States (CIS) or Australia.

5


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6

What is the difference between a TTA

and a PTTA?

Type-tested low-voltage switchgear and

controlgear assembly (TTA)

EN 60 439-1 Subparagraph 2.1.1.1:

A low-voltage switchgear and controlgear

assembly conforming to an established type or

system without deviations likely to significantly

influence the performance, from the typical

ASSEMBLY verified to be in accordance with

this standard.

A TTA is thus an ASSEMBLY which has been test-

ed as a type (manner of construction) in compliance

with EN 60 439. Examples are LV distribution

boards and Motor Control Centers (MCC). A worst-

case configuration is tested (e.g. regarding tempera-

ture rise). TTA are designed for series production,

whereby the individual TTA corresponds to the

established type, but adapted to the specific applica-

tion (e.g. number and performance of the outgoing

circuits). TTA typically possess structural parts spe-

cific to the manufacturer such as plug-in modules,

busbar systems, locking devices, etc., which are not

available as universally-applicable components.

TTA are typically applied with installations

designed for control and distribution and with

installations with high short-circuit current level.

Partially type-tested low-voltage switchgear

and controlgear assembly (PTTA)EN 60 439-1 Subparagraph 2.1.1.2:

A low-voltage switchgear and controlgear

assembly, containing both type-tested and

non-type-tested arrangements provided that

the latter are derived (e.g. by calculation)

from type-tested arrangements which have

complied with the relevant tests ().

What is considered as a low-voltage

switchgear and controlgear assembly

(ASSEMBLY) under EN 60 439?

In accordance with EN 60 439-1, Subparagraph2.1.1., a low-voltage switchgear and controlgear

assembly is

A combination of one or more low-voltage

switching devices together with associated con-

trol, measuring, signalling, protective, regulating

equipment, etc., completely assembled under the

responsibility of the manufacturer with all the

internal electrical and mechanical interconnec-

tions and structural parts ().

Note 3 states:

For various reasons, for example transport or

production, certain steps of assembly may be

made in a place outside the factory of the manu-

facturer.

Thus, an ASSEMBLY is spoken of whenever low-volt-

age switching devices and protective and regulating

equipment are involved. EN 60 439 applies for

ASSEMBLIES up to 1,000 volts a.c. and 1,500

volts d.c.

TTA are tested as a type and

are frequently optimised forspecific applications.

PTTA consist of type-tested

components, or such which arederived from them.


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PTTA are thus controls and installations which are

not tested in their entirety as a type. They are com-

piled from components which are either type-tested(e.g. contactors, circuit breakers, load break switch-

es, fuses etc.), or which are derived from type-tested

arrangements (e.g. busbar system). The temperature

rise, for example, can be derived (i.e. not mea-

sured), either

- in accordance with HD 528 S2 (IEC 890;

A method of temperature-rise assessment by

extrapolation for partially type-tested assem-

blies (PTTA) of low-voltage switchgear and

controlgear) or

- with the aid of temperature-rise calculation

software programs from enclosure manufac-

turers (which are based in turn on type-tests)

or

- based on similarity with previously manufac-

tured (and measured) ASSEMBLIES.

The essential difference between TTA and PTTA

exists in the fact that TTA are optimised for specific

(repetitious) applications and that, thanks to the

measurement, it is possible to utilize the compo-

nents to the limit of their load capacity. TTA are

procured as complete installations from one manu-

facturer or built under his licence.

In contrast to this, the PTTA construction method is

typically selected by builders of switchgear and

controlgear assemblies who opt forcomponents

from different manufacturers instead of the costly

type-test and the commitment to one manufacturer.

They derive the correct selection of the components

for their specific application from the type-tests of

the manufacturers and install them in accordance

with the established engineering practice. This

applies for single assemblies and also for series pro-

duction. PTTA generally possess more reserve (e.g.

with regard to temperature rise and the selection of

the conductor cross sections), since the derivation is

based on general rules (e.g. regarding the selection

of conductors).

TTA and PTTA are equal in regard to the fulfilment of

safety requirements.7


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8

What does EN 60 439 define?

EN 60 439 definesthe design and construction requirements which must

be fulfilled in order to achieve the safety objectives,

the definitions which are significant for ASSEMBLIES,

the referential environmental conditions,

the test requirements, etc.

EN 60 439 thus represents an extremely useful set of

instructions for the set-up and testing of ASSEMBLIES and

forms a basis for communication between manufacturer,

customer and agencies. The manufacturers and operators of

ASSEMBLIES should become familiar with EN 60 439 in

order to meet their responsibility for the safety of the equip-ment.

EN 60 439 (Low-voltage switchgear and controlgear

assemblies) is organised into the parts listed below:

EN 60 439-1 Part 1: Type-tested and partially type-tested assemblies.

EN 60 439-2 Part 2: Particular requirements for busbar trunking systems

(busways)

EN 60 439-3 Part 3: Particular requirements for low-voltage switchgear and

controlgear assemblies intended to be installed in places

where unskilled persons have access for their use

Distribution boards

EN 60 439-4 Part 4: Particular requirements for assemblies for construction

sites (ACS)

EN 60 439-5 Part 5: Particular requirements for assemblies intended to be

installed outdoors in public places Cable distribution

cabinets (CDCs) for power distribution in networks

There are supplements for some of these Parts which are integrated into the

respective basic Part upon revisions of the standards.

The following documents supplement EN 60 439 for specific areas of technology:

HD 528 S2 A method of temperature-rise assessment by extrapolation for(IEC 890) partially type-tested assemblies (PTTA) of low-voltage

switchgear and controlgear.

IEC 1117 A method for assessing the short-circuit withstand strength of

partially type-tested assemblies (PTTA)


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The contents of EN 60 439-1, the fundamental part of the regulatory ordi-

nance, are compiled below:

1. General

2. Definitions

3. Classification of ASSEMBLIES

4. Electrical characteristics of ASSEMBLIES

5. Information to be given regarding the ASSEMBLY

5.1 Nameplates

5.2 Markings

5.3 Instructions for installation, operation and maintenance

6. Service conditions

7. Design and construction

7.1 Mechanical design

7.2 Enclosure and degree of protection

7.3 Temperature rise

7.4 Protection against electric shock

7.5 Short-circuit protection and short-circuit withstand strength

7.6 Switching devices and components installed in ASSEMBLIES

7.7 Internal separation of ASSEMBLIES by barriers or partitions

7.8 Electrical connections inside an ASSEMBLY: bars and insulated

conductors

7.9 Requirements for electronic equipment supply circuits

7.10 Electromagnetic compatibility

8. Test specifications8.1 Classification of tests

8.2 Type-tests

8.3 Routine tests

Annexes

A (normative) Minimum and maximum cross-sections of copper con-

ductors suitable for connection

B (normative) Method of calculating the cross-sectional area of pro-

tective conductors with regard to thermal stresses due to currents of

short duration

C (informative) Typical examples of ASSEMBLIESD (informative) Typical arrangements of forms of separation by barri-

ers or partitions

E (informative) Items subject to agreement between manufacturer

and user

F (normative) Measurement of creepage distances and clearances

G (normative) Correlation between the nominal voltage of the supply

system and the rated impulse withstand voltage of the equipment

H (informative) Bibliography

ZA (normative) Other international publications cited in this standard

with references to the relevant European publications


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What must be observed in theand testing of a PTTA?

Type-tested components simplify work

PTTA represent the majority of control systems or

distribution boards in unit production. Observing

established engineering practice, careful selection of

products, and competent construction, the assembly

of a control system which conforms to directives

poses no problem and corresponds to the established

practice of reliable switchboard manufacturers.

The documentation of the component manufacturers

are an essential support tool for project planners as

well as the builders of ASSEMBLIES. In accordance

with the Low-Voltage and the EMC Directive, all

components must fulfil the relevant directives and be

type-tested. The type-tests of the components are

performed in compliance with the respective stan-

dards for the components (e.g. in compliance withEN 60 947 for low-voltage switching devices) and

not in compliance with EN 60 439 (refer to EN

60 439-1 Subparagraph 1.1: This standard does not

apply to individual devices and self-contained com-

ponents, such as motor starters, fuse switches, elec-

tronic equipment, etc., complying with their relevant

standards).

The component manufacturers issue relevant

Declarations of Conformity and identify theproducts for the EU with the CE-mark. The user of

such type-tested components can assume that the

relevant standards are fulfilled, provided that these

components are installed in accordance with the

manufacturers specifications (those which form the

basis of the type-test). This applies for the areas of

the Low-voltage Directive as well as the EMC

Directives for the utilisation of other

components as those applied for the

type-test of a TTA permit a range of

freedom

EN 60 439 states in Subparagraph 8.1.1:

If modifications are made to the components

of the ASSEMBLY, new type tests have to be

carried out only in so far as such modifica-

tions are likely to adversely affect the results

of these tests.

This rule provides the manufacturer of a specific

TTA a relatively wide range of freedom regarding

the selection of the switchgear and other compo-

nents. It is entirely feasible that devices other than

those employed in the type-test may be installed

without affecting the validity of the type-test, for

example when:

- the maximum temperature rise is not exceeded

(e.g. through selection of devices of the same

or lower power dissipation),

- the insulation withstand strength is not low-

ered (e.g. through selection of devices of the

same or better insulation),

- the short-circuit withstand strength is main-

tained (e.g. through selection of circuit break-

ers with the same or higher breaking capacity

and the same or more favourable let-through

values).


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construction, modification

Directive. Among other things which deserve special

attention are the manufacturers specifications

regarding load capacity with increased ambient tem-

perature, the performance data for short-circuit

stress, the safety distances from arcing apertures,

etc.

The job of the ASSEMBLY manufacturer is simpli-

fied if he can refer to type-tests or technical docu-

mentation from the component manufacturer forcomponent subassemblies, as is the case with the

MCS-Star provided by Rockwell Automation for

motor starters of the Modular Control System

(MCS). He is thus freed from the burden of select-

ing and dimensioning the components installed in

the subassembly.

The added value performed by the

ASSEMBLY maufacturer requires

safety verification

While it is possible to rely upon the type-tests con-

ducted for devices by the component manufacturer,

the ASSEMBLY manufacturer bears the responsibil-

ity for work he has performed, such as selectingcorrectly-dimensioned conductors and their protec-

tion. Here, he can rely upon the relevant guidelines

such as those set down in Harmonization Document

HD 384.5.523, with consideration for the type of

conductor, the temperature limit of the conductor

insulation, the ambient temperature, the conductor

loading and the method of installation.

Helpful software tools such as

MCS-Star produced by Rockwell

Automation simplify the work of

ASSEMBLY manufacturers.

Which starter?

Starter selection

Circuit diagram

Layout

Assembly test

Starter selection

Catalog Nr.

Bills of Materials Circuit diagram Project Terminate

Function

Star-Delta starter

Mechanical locking

Without mechanical locking

Control type

Short-circuit coordination

Coordination Type "1"

Control voltage

220-230V 50Hz

230V 50 / 60Hz

230-240V 50Hz

240V 50Hz / 277V 60Hz

Motor protection

Electrical motor protection relay,terminal 10 man.

Current limiter

Star-Delta time relay

Electronic timer module, 30 seconds

Assembly system

Motor output at 400 /415 V 50 Hz

7.50 kW / 14.8 A

9.00 kW / 19.0 A

11.0 kW / 21.5 A

15.0 kW / 29.0 A

170-C16NKF10-A1G-TY-E-X

Layout

Circuit diagram 170-005 Layout S00SEATX


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Calculation software simplifies

verification of the temperature rise

Harmonization Document HD 528 S2 (IEC 890)

applies as the established engineering practice for

the determination of the temperature rise in the

switchgear cabinet with natural cooling.

Suppliers of enclosures and cabinets provide soft-

ware for temperature-rise calculation based on

proven calculation methods and which allow verifi-

cation of temperature rise and any cooling measures

required without undue outlays for the user.

The project planner takes the power dissipation of

the components from the catalogues or databases of

the product manufacturers, while the software

ensures the correct sizing.

In the event that similar control units (e.g. same

cabinet size with comparable power dissipation of

the components in a similar construction) are built

successively, the verification for temperature rise

can also be derived from the observance of similari-

ty with the first system whose temperature rise was

either measured or calculated.

Special care with short-circuit

currents above 10 kA

EN 60 439 exempts testing of short-circuit with-

stand strength at rated short-circuit currents below

10 kA. Nor is verification of the short-circuit with-

stand strength required for protection with current-

limiting devices such as current-limiting fuses or

circuit breakers when the let-through current does

not exceed 15 kA at rated breaking capacity.

As a result, significant costs for testing are eliminat-

ed for many control systems and installations.

Short-circuit currents of 10 kA presuppose the

direct connection to a transformer with an output of

approx. 400 kVA (at 400 V secondary voltage and

6% short-circuit voltage) and are rare with smaller

loads. Because of the hazards of short circuits,

extreme caution regarding the short-circuit with-

stand strength should be taken and it must be

ensured that either the limits of 10 kA and 15 kA

respectively are not exceeded, or that the installation

possesses the necessary robustness at higher levels

of short circuit current.

It is advisable to rely upon type-tested components

and arrangements, even for PTTA where busbars are

involved. The selection and application of the bus-

bar in compliance with manufacturers specifica-

tions (based on his type-test) ensures a design that

conforms to requirements.

In addition, Technical Report IEC 1117 provides

instructions for the design of PTTA which is resis-

tant to short-circuits, especially regarding connec-

tion of the equipment.

Current limiting circuit breakers can

eliminate the necessity for verifica-

tion of short-circuit withstand

strength.


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Which tests must be performed on PTTA?

Table 7 of EN 60 439-1 lists the tests which are tobe performed on PTTA (and TTA). In the selection

of type-tested components, or those derived from

them, and for the execution of calculations in com-

pliance with recognised methods, verification may

be achieved without difficulties.

It is recommended that standardised protocols are

prepared for the documentation of the tests or

whenever available that protocol forms made

available by professional societies are used.

How can the expense for the technical

verification of PTTA be minimised?

Together with the selection of type-tested compo-

nents for which no further verification is required

since reference may be made to the type-test of the

respective manufacturer, it is recommended to stan-

dardise the internal bespoke documentation and pro-

cedures for the services of the planning engineerand builder of ASSEMBLIES and to incorporate

these standards into a quality assurance system.

Given careful work in compliance with these inter-

nal standards, technical verification for all installa-

tions assembled in compliance with them is guaran-

teed. With sizing for which either standards or

industry-specific table references are available, for

example, it is recommended that these be incorpo-

rated. It may be anticipated that industrial societies

will support their members increasingly in the fulfil-ment of this task.

Important notes regarding national

differences

The standards and Harmonization Documents

referred to in this brochure are cited with the num-

bers and designations in accordance with CEN-

ELEC or IEC. The numbers and designations may

deviate in some countries because of national sys-

tems. However, the national standards are identi-

cal in their contents and cite the documents

which form the basis at the European level in all

cases.

Software for calculation of temper-

ature rise and short-circuit current

are helpful support tools.

Careful routine testing

ensures the safety of the

individual ASSEMBLY.

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Compilation of verifications and tests of TTA and

recommendations for the practical execution with

Seq Requirements Section TTA

no. to be tested

1 Limiting excess 8.2.1 Verification of compliance

temperature of limiting excesstemperature by testing (type-test)

2 Insulation withstand 8.2.2 Verification of the insulation

strength withstand strength by testing

(type-test)

3 Short-circuit 8.2.3 Verification of short-circuit withstand

withstand strength strength by testing (type-test)

4 Efficiency of the 8.2.4 Verification of the proper connection

protective conductor between conductive parts of the


Proper connection between 8.2.4.1 assembly and protective conductors

conductive parts of the by inspection or resistance measurement

switchgear and controlgear (type-test)

assembly and protective

conductors

Short-circuit withstand 8.2.4.2 Verification of the short-circuit withstand

strength of the protective strength of the protective conductor

conductor by testing(type-test)

5 Creepage distances and 8.2.5 Verification of the creepage

clearances distances and clearances

(type-test)

6 Mechanical 8.2.6 Verification of the mechanical

function function (type-test)

7 Type of protection 8.2.7 Verification of the type of protection

(type-test)

8 Wiring, 8.3.1 Visual inspection of the switchgear and

electrical function controlgear assembly, including the wiring

and electrical function test where required

(routine test)

9 Insulation 8.3.2 Insulation test

(routine test)

10 Protective measures 8.3.3 Inspection of protective measures and visual

inspection of the continuous protective

conductor connection (routine test)

11 Leakage resistance 8.3.4 -

Subparagraphs 8 to 11 are routine tests


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PTTA (Table 7 from EN 60 439-1) supplemented with

PTTA.

PTTA Comments for PTTA

Verification of compliance Determination in accordance with HD 528 S2 or

of limiting excess temperature with the use of temperature-rise calculationby testing or extrapolation of TTA software from enclosure manufacturers

Verification of the insulation withstand The verification of the insulation resistance

strength in compliance with Section 8.2.2 (measurement at 500 V) will be the

or verification by insulation test in com- easiest to conduct in most instances.

pliance with Section 8.3.2 or verification

of the leakage resistance in compliance

with Section 8.3.4 (refer to Seq. no. 11)

Verification of short-circuit withstand Not required up to 10 kA (or 15 kA let-through current respectively).

strength by testing or extrapolation of Beyond this, use of type-tested busbar systems recommended.

similar type-tested arrangements Extrapolation in accordance with manufacturer's documents and

execution in accordance with IEC 1117.Verification of the proper connection

between conductive parts of the


assembly and protective conductors

by inspection or resistance measurement

Verification of the short-circuit withstand For PTTA, separate protective conductors must be provided (protective

strength of the protective conductor by connections via constructional parts are not allowed) in such a manner

testing or corresponding execution and that the influence of the electromagnetic forces of the busbars may bearrangement of the protective conductor ignored (i.e., at a distance from the busbars).

(refer to Section 7.4.3.1.1, last paragraph)

Verification of the creepage Use of type-tested components and special attention to the clearances

distances and clearances from enclosures and other conducting parts.

Observance of arcing spaces.

Verification of the mechanical Especially for plug-in modules and locking devices. Occurs rarely with

function PTTA or is covered by the use of type-tested components.

Verification of the type of protection Use of suitable type-tested enclosures and installation components.

Installation of components in the switchgear cabinet surface in

compliance with instructions of the component manufacturer

for the relevant type of protection.

Visual inspection of the switchgear and

controlgear assembly, including the

wiring and electrical function test

where required

Insulation test or verification of the See note regarding Subparagraph 2

leakage resistance in compliance with

Section 8.3.4 (refer to Seq. no. 11)

Inspection of protective measures Visual inspection of the protective conductor connections and random

sample tests of the threaded connections.

Verification of the leakage resistance, See note regarding Subparagraph 2

if the test was not conducted in com-

pliance with Section 8.2.2 or 8.3.2

(refer to Seq. no. 2 and 9)


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