Adding another circuit !

Spike1947 · Apr 21, 2024

Have a 63A RCD 5 Way box, with a 45A MCB, feds by 16mm2 tails, this in then feeding into a isolator via 10mm2 T&E, that then supplies the feed to a 6.5KW heater that is used prob once a month for 10 min intervals max.

Question: I have a spare 63A RCB + 20A MCB box, Can I take another feed from the input of the 63A isolator to feed that, then that would feed into the next building to feed a compressor, some sockets etc via 4mm2 T&E ?.

cheers
Spike

ipf · Apr 21, 2024

Given up trying to decipher that little lot. Sorry!
Not going to start presuming.

westward10 · Apr 21, 2024

What is a five way box?

mainline · Apr 21, 2024

Spike1947 said:
Have a 63A RCD 5 Way box, with a 45A MCB, feds by 16mm2 tails, this in then feeding into a isolator via 10mm2 T&E, that then supplies the feed to a 6.5KW heater that is used prob once a month for 10 min intervals max.

Question: I have a spare 63A RCB + 20A MCB box, Can I take another feed from the input of the 63A isolator to feed that, then that would feed into the next building to feed a compressor, some sockets etc via 4mm2 T&E ?.

cheers
Spike

Lots of pictures may help of each item and where the 16mm tails originates along with what else it feeds.

timhoward · Apr 21, 2024

mainline said:
Lots of pictures may help of each item and where the 16mm tails originates along with what else it .

To be honest I'm doubting we will reach the threshold of information required to say for certain "yes, this is safe, go ahead". It's not changing a light fitting, it's a very general question about adding distribution circuits, and I don't think we should be signing off the design over the internet.

mainline · Apr 21, 2024

timhoward said:
To be honest I'm doubting we will reach the threshold of information required to say for certain "yes, this is safe, go ahead". It's not changing a light fitting, it's a very general question about adding distribution circuits, and I don't think we should be signing off the design over the internet.

Very true, but I wouldn't mind seeing the pics
Previous posts of the OP related to a 3ph TT farm.

littlespark · Apr 22, 2024

What I can understand is he wants to come off the supply side of a cu mainswitch, run an swa to another building to feed another cu.

If there is no space to give it an mcb within the board, I would suggest splitting before the first cu with Henley’s, an isolator and fusing the swa down.

The “5 way rcd box” is irrelevant. It only suggests the entire circuit is rcd protected at source and is on a 45A OCPD.

timhoward · Apr 22, 2024

littlespark said:
The “5 way rcd box” is irrelevant

I know what you mean, but the 16mm tails could mean 60A supplier fuse, and max demand of the whole lot might be a consideration.

littlespark · Apr 22, 2024

timhoward said:
I know what you mean, but the 16mm tails could mean 60A supplier fuse, and max demand of the whole lot might be a consideration.

Indeed.

Sounds as though the only extra load is a 20 and a 6 breaker… could just be a light and a socket… or could just as likely be a dozen lights and any number of sockets… but max 26A

The only issue might be during the 10 minutes that the big heater is on.

Reading it again, it also seems like he’s running this new part in t&e…. Which is wholly unsuitable.