Integration in power distribution equipment
7.4 Requirement according to IEC 61439
3WA1 air circuit breaker
Equipment Manual, 02/2023, 92310000002-06
527
7.4.2 Simplified integration
7.4.2.1 Structural integration in power distribution equipment
A 3WA circuit breaker can be installed without any testing or structural changes if
a 3WL circuit breaker has already been tested in the power distribution equipment.
The technical requirements for this are defined in IEC 61439-1:
• The installation dimensions (terminals, cross-sections and mounting points) remain
unchanged.
• The thermal losses and derating values of the circuit breaker are the same or better.
• The arcing spaces are the same size or smaller.
• The required main conductor connection cross-sections remain the same.
• The copper connections stay the same.
• The short-circuit breaking capacity (short circuit values I
cw
) for the power distribution
equipment remain the same.
• The insulation conditions (required clearances and creepage distances) remain the
same.
• The EMC classification is the same or higher.
• The mechanical functions and operation remain the same.
• The power distribution equipment design is unchanged.
You can find detailed information in Chapter Checklist for replacing 3WL with 3WA
circuit breaker according to IEC 61439-2 (Page 535).
circuit breaker is integrated, no m
echanical changes are required for integration
of the 3WA
circuit breaker.
Checks and tests
A short-circuit test is only necessary when the following two conditions are fulfilled:
• Unlike the existing 3WL circuit breakers with article numbers 3WL….-…3.-…. and
3WL….-…4.-…., the power distribution equipment is to be adapted to the higher
short-circuit breaking capacity of the 3WA circuit breakers.
• The higher values of the 3WL circuit breakers with article numbers 3WL….-…6.-….
and 3WL….-…7.-…. have not been tested yet.
If the power distribution equipment is not designed for the increased short-circuit values,
the operator must make structural changes to the switchboard design.
No further tests (e.g. temperature-rise tests and EMC tests) are required.
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