20Amp ring

[toasty]

Just a curiosity really.

2.5mm can carry about 27A and can be used in a ring main configuration for 30/32amp.

1.5mm can carry about 18A, so could it be used for a 20A ring main, if I so desired?

Is there anything in the regs that says I can't do this?

 

[davelx]

There's no reg that says you cannot do it if you are prepared to do and document all the design calculations required to ensure that it is safe and will work correctly.

However, the standard ring final circuit for BS1363 sockets and FCUs (OSG table 8A pg 151) specifies 2.5mm cable and there is a minimum current capacity of 20A for the cable with 32A MCB OPD.

If you use 1.5mm and a B20 it's not compliant to the standard circuit so you cannot make assumptions, you have to do the design work.

 

[Spark123]

Why would you want to do it? Like DaveLX says it isn't really streight forwards. The only reg I can think of regarding ring final circuits says something along the lines of 2.5mm with a 32A protective device unless you are using pyro.
If you want a 20A circuit then why not run it as a radial in 2.5?

 

[toasty]

I don't want to do it. It was more a theoretical question.

 

[Taylortwocities]

Can someone tell me how to get to Baldock from Oxford.
I dont want to go there, its just a theoretical question

 

[toasty]

Can someone tell me how to get to Baldock from Oxford.
I dont want to go there, its just a theoretical question

Is there something wrong with you?
I was just curious if ring finals were specifically intended only for 2.5mm, or if in theory they could be implemented using smaller (or indeed larger) cable than the standard 2.5mm, there's no need for you to take the Mick.

Thanks for the sensible answers.