Disconnection times

[jackfrosty]

Hi, im a bit confused over all these disconnection times. Ive read that a circuit that is 32a or under has a disconnection time of 40ms (0.4s) but a circuit over 32a has to disconnect within 5seconds. Does this mean a shower b40 breaker doesnt have to diconnect for 5 seconds? Sounds dangerous? Are these times for the RCD or MCB(fuses)

Cheers for advise

Dan

 

[Andy™]

disconnection times are for MCB's. RCD's have lower trip times of either 300 or 200ms at 1x, and 40ms at 5x

 

[Chr!s]

You could have a distribution circuit under 32 with a 5 sec disconnection reg 411.3.2.2

0.4 is not 40 ms(0.04)

Does this mean a shower b40 breaker doesnt have to diconnect for 5 seconds? Sounds dangerous? Are these times for the RCD or MCB(fuses)

Thats correct, though the max zs for mcbs table 41.3 applys for both .4 and 5 sec

Also shower requires rcd protection.

 

[Chr!s]

disconnection times are for MCB's. RCD's have lower trip times of either 300 or 200ms at 1x, and 40ms at 5x

Andy

The disconnection times apply to both rcd and mcb