Earth Commoning Block

[c1223]

This isn't technically home DIY but I think the answer should be the same. I have a power system with an incoming supply of 125A 3ph. This is split to several 16A sockets. Let's take 6 for example:

I have 6x 16A sockets the are downstream of individual RCBOs which themselves are downstream of a 125A MCCB. If I connect all the earths of the 16A sockets to an earth commoning block, which is in turn connected to the earth of the 125A, does the commoning block have to have a current rating of 125A? Surely not, and presumably we hope that a short circuit fault doesn't occur on all 6 sockets at the same time...?

 

[Taylortwocities]

If you have six separate sockets, each with their own RCBO, then surely the earths of each circuit connect to the earth terminal bar inside the consumer unit/DB/etc.

 

[c1223]

In this case it isn't a CU, but hypothetically in a 100A CU, is the earth terminal bar rated to 100A?

 

[EFLImpudence]

It's the same as the Line and Neutral bars - so ...

 

[c1223]

Makes sense. Thanks!

 

[ban-all-sheds]

Makes sense.

But what doesn't is why you are having to ask these questions on a DIY advice site.