Bathroom circuit

[Shift]

Going to be fitting a ventilation fan and a mirror with led lights and demister pad. I have already run a 4mm radial circuit back to rcd side (16 amp mcb) of the split load consumer unit for the shower pump via a 5amp fcu, is it ok to spur off the fcu for the mirror and fan using their own 5amp fcu's.

 

[GaryMo]

Yes but why 4mm for a 16A radial? Thermal insulation?

 

[Shift]

All of the radial circuits in my house are 4mm and I read on here that radial circuits should be 4mm, are you saying 2.5mm would have been ok for this small circuit.

 

[ban-all-sheds]

I read on here that radial circuits should be 4mm,

I don't think you did.

Your lighting circuits are radials - I bet they aren't done with 4mm²




But did you read on here that you should have notified your local council before starting this work?

are you saying 2.5mm would have been ok for this small circuit.

It would have been fine. In fact, 1.5mm² would probably have been fine, and if you'd dropped the MCB to 6A you could have used 1mm².

You need to swot up on the relationships between cable sizes and breaker ratings...

 

[Shift]

ban all sheds
You know what I meant we're not talking about lighting circuits are we

So ok I will re-phrase that all of the 13a sockets apart from the kitchen are 4mm, I don't know why but they are.

I'm afraid you are wrong I did read on here to run radial circuits in 4mm obviously I assumed the op was correct as my house is wired with 4mm but after digging out regs he is wrong and you are correct.

I think the consensus is to use the best for the layout of the house. Wire your radials in 4mm² cable, so they can be 32A and therefore not restricted. But if you can do a ring final, these are the most popular to install. 2.5mm² is easier to work with.

And yes I did and have

But did you read on here that you should have notified your local council before starting this work?

 

[ban-all-sheds]

Radial socket circuits, yes.

Radial circuits with a 32A protective device, yes.

But you've installed a circuit which is neither, and you've used cable which is far bigger than it needs to be for the load it is going to support, and far bigger than it needs to be for the rating of the breaker it's on. Nothing wrong with that if it's a conscious decision relating to future-proofing, but in your case you did it because of ignorance.

You would be well advised to learn more about circuit design before embarking on any more projects.

 

[jockspark]

Radial socket circuits, yes.

Radial circuits with a 32A protective device, yes.

But you've installed a circuit which is neither, and you've used cable which is far bigger than it needs to be for the load it is going to support, and far bigger than it needs to be for the rating of the breaker it's on. Nothing wrong with that if it's a conscious decision relating to future-proofing, but in your case you did it because of ignorance.

You would be well advised to learn more about circuit design before embarking on any more projects.

give the guy a break nothing he has done is dangerous he is asking advise
to further his knowlege help or get of his back for someone who has not completed his eal domestic intsallers LEVEL2 dont be so arrogant

 

[Shift]

Yes I'm a very ignorant person

Because you have been so helpful with out being patronizing at all
I will be changing the wire for 2.5mm.

ban
Just remember this is a DIY forum to help people who seek out knowledge to enable them to do things correctly and most importantly safely,do you really think I would endanger my family and break the law. If i wanted to do that why would I bother asking for expert advice.
You don't know peoples backgrounds so don't make assumptions

 

[Shift]

Thanks for the backup jockspark

ban
Does this mean you are

someone who has not completed his eal domestic intsallers LEVEL2

 

[jockspark]

bryan there is no need to change it leave it as it is

 

[Shift]

Thanks for that jockspark,it's not to much trouble to change it so probably will.

 

[ban-all-sheds]

jock - I'm not on his back, or being arrogant.

Everything I said was completely true - do you think that he installed a 4mm² radial on a 16A breaker to supply a load of a few amps because he understood the principles of circuit design or because he was ignorant of them?

Do you think he should carry on doing jobs in ignorance or do you think he should improve his skills? Can you guarantee that his ignorance would never lead to him doing something dangerous?

You say I should help him - in what way is advising him to advance his knowledge unhelpful? In what way is advising him of legal implications of his work of which he may have been unaware unhelpful?

I did, however, only reply to his posts on the 4mm² issue, (but then so did Gary, and I don't see you having a go at him). Nor do I see you helping him with an answer to the question he actually asked....

is it ok to spur off the fcu for the mirror and fan using their own 5amp fcu's.

You won't be "spurring off" - just keep taking the circuit cable from one set of FCU supply terminals to the next.

ban
Does this mean you are

someone who has not completed his eal domestic intsallers LEVEL2

No.