Please, see diagram and slap me if I am wrong ;)

[mechelec]

yes. but most of these numptie posters don't work on TT and think they can use a single RCD, up front, to save money, which isn't a good idea.

Good point.

 

[guest119]

The OP diagram shows a 100a isolator feering a 63 amp rcd., not rcbo
Therefor rcd can be provided with more current than it can safely handle.

Boydy

 

[mechelec]

The OP diagram shows a 100a isolator feering a 63 amp rcd., not rcbo
Therefor rcd can be provided with more current than it can safely handle.

Boydy

Why has the rating of his isolator got anything to do with how much current the RCD will see ? (As already stated in previous post RCD should be RCBO) As long as an isolator has a higher rating than it's supplying protective device (whose rating is not shown) it is irrelevant. It could be a 1000a isolator but if it was being supplied by a 60a fuse it would be fine ( overbuilt yes but electrically safe)
in industrial installations especially bus bar set ups very often the OCPD for the bus bars is a much higher ration of the switch fuses they supply.

 

[guest119]

Why has the rating of his isolator got anything to do with how much current the RCD will see ? (As already stated in previous post RCD should be RCBO) As long as an isolator has a higher rating than it's supplying protective device (whose rating is not shown) it is irrelevant. It could be a 1000a isolator but if it was being supplied by a 60a fuse it would be fine ( overbuilt yes but electrically safe)
in industrial installations especially bus bar set ups very often the OCPD for the bus bars is a much higher ration of the switch fuses they supply.

Because it looks like the op has fell into the trap of thinking a 63a rcd will provide overcurrent protection, for his 16mm tails thereafter.


Boydy