Ax disconnection times 32A+

[gazdkw82]

I don't know why I've not noticed before but the disconnection time for final circuits greater than 32A is 5 secs on a TN earthing arrangement. Does that mean a shower has a disconnection time of 5 secs? Although this circuit would also fall under protection of an RCD??

Also, cooker circuits would fall in this as would many other designated circuits. So, this is related to ADS? So in order to meet disconnection times our circuit Zs would need to be compliant with specified limits. The Z's values listed for say a 40A type B, is that figure based on the circuit disconnecting within 5secs or 0.2secs?

Bit early for this and I'm probably over thinking this haha

 

[Ian1981]

For TN your typical values Are o.4 seconds final circuits upto 32 amps , sockets upto 63 amps and 5 seconds for distribution circuits and final circuits above 32 amps.
This is based upon fault protection afforded by the ocpd and not for additional protection via an rcd in accordance with 415.1.1

 

[gazdkw82]

So between 32A and 63A it's 5secs?

My point is, if a circuit is not additionally protected by an RCD then a 40A circuit is allowed a 5 sec disc time ?

 

[Ian1981]

So between 32A and 63A it's 5secs?

My point is, if a circuit is not additionally protected by an RCD then a 40A circuit is allowed a 5 sec disc time ?

Yes