# IEEE C37.13a-2012 pdf free

**IEEE C37.13a**-2012 pdf free.IEEE Standard for Low-Voltage AC Power Circuit Breakers Used in Enclosures Amendment 1: Increase of Voltages to 1000 V AC and Below.

Change item a) as follows:

Stationary or drawout type of two, three-, or four-pole construction with one or more rated maximum voltages of 1058 V, 730 V, 635 V (600 V for units incorporating fuses), 508 V, and 254 V for application on systems having nominal voltages of 1000 V.690 V.600 V, 480 V, and 240 V respectively.

Ratings Rated maximum voltage

Change 5.2 as fllows:

The rated maximum voltage of a circuit breaker is the highest rms (root mean square) voltage, three phase or single-phase, at which it is designed to perform. The circuit breaker shall be rated at one or more of the following maximum voltages: 1058 V.730 V.635 V, 508 V, or 254 V. For fused circuit breakers, the 635 V rated maximum voltage becomes 600 V to match the fuse rating.

Test procedures Test values Test voltage values

Change item a) as follows:

a) Primary circuit of a new, completely assembled circuit breaker

1) 2200 V for circuit breakers with maximum voltage rating of 635 V and below

2) 3000 V for circuit breakers with maximum voltage ratings of above 635 V.

Application guide General Short-circuit current Motor contribution

Change item b) as follows:

b) For nominal system voltages of 240 V to 1000 V600￥, it should be assumed that the load is 100% motor load and, in the absence of exact information, that 25% of the motors are synchronous and 75% induction. This corresponds to an equivalent symmetrical contribution of approximately four times the full-load current.IEEE C37.13a pdf free download.