Saturday, November 9, 2013

The new IEC 61439 standard

The new IEC 61439 standard applies to enclosures

for which the rated voltage is under 1000 V AC

(at frequencies not exceeding 1000 Hz) or 1500 V DC.

The standard defines the design verified ASSEMBLIES

and eliminates completely the categories TTA and PTTA.

In order to conform to the standard, type tests have been

replaced by a design verification which can be carried

out by the three following equivalent and alternative

methods: testing, calculation/measurement or

application of design rules.

 

The following parts are mentioned and do not have equal

weighting. There is a formal hierarchy. Each part cannot be

used individually:

 

−− IEC 61439-1 "General rules"

−− IEC 61439-2 "Power switchgear and control gear ASSEMBLIES"

−− IEC 61439-3 "Distribution boards"

−− IEC 61439-4 "ASSEMBLIES for construction sites"

−− IEC 61439-5 "ASSEMBLIES for power distribution"

−− IEC 61439-6 "Busbar trunking systems"

 

Part 1 is the general rules part and cannot be used alone to

specify an ASSEMBLY.

 

Part 2 defines the specific requirements of power switchgear

and controlgear ASSEMBLIES (PSC ASSEMBLIES) and must

be used with Part 1. This is the only part that has a double

role, it covers PSC ASS EMBLIES and any ASS EMBLY which

is not covered by any other specific parts.

 

Parts 3-X are still under preparation but are already mentioned

in Part 1. These could be more than four, as additional

parts may be developed as the need arises.

 

Summarising:

With the currently used IEC 60439, the rule

is "one part for each type of ASS EMBLY". With the new

IEC 61439 the rule is "two parts for each type of ASSEMBLY".

The compliance of an ASSEMBLY is declared referring

to the specific ASS EMBLY standard (e.g. IEC 61439-2),

and the compliance with the general rules (IEC 61439-1) is

always implicit. The sentence "TTA switchgear according to

IEC 60439-1" is now replaced by "Power switchgear and

 

controlgear

ASSEMBLIES according to IEC 61439-2, design

verified ASS EMBLY".

The validity of the two standards will overlap until 2014 and

prior to this date, ASSEMBLIES can be manufactured according

to IEC 61439 or IEC 60439.

 

Copyright by :

ABB The new standard for low-voltage

switchgear and controlgear assEmblies

IEC 60529 First Characteristic Numeral Degrees of Protection - Water

INDOOR

 

IP X1 Vertical Falling Drops           10 Min. Drip Test                              Limited Water Inside;

Not on Live Parts

 

IP X2 15° Vertical Falling Drops    10 min. 15° Drip Test                       Limited Water Inside;

Not on Live Parts

 

IP X3 Spraying Water                      5 min. 120° Oscillating Tube or

5 min. Partial Spray

Limited Water Inside;

Not on Live Parts

 

IP X4 Splashing Water                    10 min. 360° Oscillating Tube

or 5 Min. Full Spray

Limited Water Inside;

Not on Live Parts

 

IP X5 Waterjets                                                 Fire Hose 3.3 gal. (12.5L)/min      Limited Water Inside;

Not on Live Parts

 

OUTDOOR

 

IP X6 Powerful Waterjets             Fire Hose 26 gal. (100L)/Min.       Limited Water Inside;

Not on Live Parts

 

IP X7 Temporary Submersion at Limited Depth   Submerge 3 ft. (1m) – 30 Min.    Limited Water Inside;

Not on Live Parts

 

IP X8 Prolonged Submersion at  Limited Depth More Severe Than X7 Customer Agreement         Limited Water Inside;

Not on Live Parts

IEC 60529 First Characteristic Numeral Degrees of Protection - Solids

>> IEC 60529 First Characteristic Numeral Degrees of Protection – Solids

 

Protection Test Method Pass Criteria

 

INDOOR

 

IP 1X Incidental Contact & Solid Objects Ø 50 mm – Probe No Penetration

IP 2X Incidental Contact & Solid Objects Ø 12.5 mm – Probe No Penetration

IP 3X Incidental Contact & Solid Objects Ø 2.5 mm – Probe No Penetration

IP 4X Incidental Contact & Solid Objects Ø 1.0 mm – Probe No Penetration

 

OD

 

IP 5X Dust Protected Circulating Dust Limited Dust Inside; Not on Live Parts

IP 6X Dust Tight Circulating Dust No Dust Inside

 

Thursday, October 24, 2013

Methods of explosion protection for electrical equipment

METHODS OF EXPLOSION PROTECTION

Method                                                                                               Type of Protection

Designed to prevent any means of ignition arising            Ex e Increased Safety

Ex n or Ex N Non Sparking

Designed to limit the ignition energy of the circuit            Ex I Intrinsic Safety

Designed to prevent the flammable mixture reaching    Ex m Encapsulation

a means of ignition                                                                          Ex p Pressurisation

Ex o Oil Immersion

Ex nR or Ex N Restricted Breathing

Designed to prevent any ignition from spreading              Ex d Flameproof Enclosure

Ex q Powder Filling

 

Saturday, October 19, 2013

Minimum terminal capacity for copper protective conductors (PE, PEN)

CROSS-SECTIONAL AREA OF PHASE CONDUCTORS S
MM2

MINIMUM CROSS-SECTIONAL AREA OF THE CORRESPONDING PROTECTIVE CONDUCTOR (PE, PEN) SPA
MM2

S ≤ 16

S

16 < S ≤ 35

16

35 < S ≤ 400

S/2

400 < S ≤ 800

200

800 < S

S/4

a Current in the neutral may be influenced where there are significant harmonics in the load.

Minimum terminal capacity for copper protective conductors (PE, PEN)

Source: IEC 61439-1 2011 Table 5

 

Saturday, October 12, 2013

Standard-compliant switchgear and controlgear production (Application of IEC 61439)

 

A new standard. A new opportunity. 3

Contents 4

One standard for all switchgear and controlgear assemblies 6

What has changed under the new standard? 8

What does the new standard mean for you? 10

Rittal – The System.

Complete solutions – Customised for IEC 61439 12

Strength of materials 14

Protection category of enclosures 16

Verification of protective circuit function 18

Insulating properties 20

Calculation of temperature rise 22

Tested busbar technology 24

The system for the standard 26

 

Preparation of the design verification 28

 

I. The design verification 29

II. Individual verifications and verification methods 31

III. Information included in the design verification 32

IV. Sample design verification 44

V. Verification of temperature rise using calculations 48

VI. Verification of short-circuit withstand strength 66

VII. Verification records of individual

switchgear and controlgear assemblies 70

VIII. The routine verification 73

IX. Complete verification of a switchgear and

controlgear assembly 78

X. Assembly cover sheet and design verification form 80

 

Copyright: c 2013 Rittal GmbH & Co. KG

 

DOWNLOAD :

http://www.rittal.com/belgium/downloads/brochures/eng/IEC61439_compliant_switchgear_controlgear_production.pdf

Guide to migration from IEC 60439 to IEC 61439 (XL3 Confugurable Assemblies IEC 60439 >>> IEC 61439)

This document only deals with  distribution enclosures for advanced users (authorised persons), i.e. parts 1 and 2 of the new standard. Part 3 of standard IEC 61439 discusses DBO (Distribution Boards intended to be operated by Ordinary persons) only up to 250 A. One of the new features of this standard is that the table in appendix D (checking the design) covered laterin this document does not apply in 61439-3.

In addition in its new version, standard 61439-3 takes account of domestic normative references.

 

DOWNLOAD :

 

http://www.export.legrand.com/files/fck/pdf-EN/EXB12074_GUIDE_TABLEAUTIERS_EN.pdf

Saturday, October 5, 2013

Saturday, September 14, 2013

Measurement of the insulation resistance

- the insulation resistance must be measured with amegohmmeter (external or with standalone source) at

a minimum voltage of 500 VDC

- the assembly being tested must be turned off and there must be no receiver devices connected

- all the breaking devices must be in position i (on)

- the voltage is applied between each circuit and the exposed conductive part

- it is possible to link all the poles: phases and neutral,except in tnC layout in which the pen conductor is considered to be linked to the exposed conductive part

of the assembly.Devices (measurement windings, instruments) which would not withstand the test voltage must have their supply terminals short-circuited.

the measurement conditions can influence the results obtained. measurements should not be carried out temperatures below dewpoint (condensation will

dampen the surfaces).

the insulation resistance decreases with the temperature.if repeated measurements have to be taken,the environmental conditions must be recorded. the period for which the voltage is applied also has a major influence, and measurement can be considered to consist of three sequences. at the start of measurement, the device charges the capacitor which represents the installation in relation to earth and the leakage current is at its highest.

 

LEGRAND POWER GUIDE

Enclosure resistance to damp

This test, carried out in accordance with standard

ieC 60068-2-3, checks that the insulation characteristics

of the enclosure, busbars and conductor supports

are not affected after 4 hours' exposure in a steam

chest (40°C at 95% relative humidity).

the insulation used has a tracking current resistance

of at least 400 V, which means it is not very sensitive to

damp (group i and group ii according to ieC 60664-1).