cable size?

[alanwheeldon]

Hi guys this is my first post on this site, i need some help please.

Ive just bought a seperate RCD shower unit for a 9.5kw shower as the consuner unit is not RCD protected. It is a 63A 30mA RCD and includes a 50A MCB. What size supply cable is required from the consumer unit to the RCD and where abouts does the RCD need to go in the circuit.

 

[RF Lighting]

16.0mm² minimum

 

[alanwheeldon]

I thought it would be around that size, thanks very much.

 

[ban-all-sheds]

Enjoy....

 

[GaryMo]

Ive just bought a seperate RCD shower unit for a 9.5kw shower as the consuner unit is not RCD protected. It is a 63A 30mA RCD and includes a 50A MCB. What size supply cable is required from the consumer unit to the RCD?

Are you supplying the (1-way?) RCD shower unit from an existing MCB in your consumer unit? If so then 10mm² will be fine (rated at 64A clipped direct).

 

[Taylortwocities]

Are you supplying the (1-way?) RCD shower unit from an existing MCB in your consumer unit? .

That's assuming your existing fusebaord can support such a load. many older ones can only provide a max of 30amps per fuse.

 

[GaryMo]

An alternative would be to supply the RCD shower unit with 10mm² double insulated tails from a henley block.

 

[alanwheeldon]

There is no space in the CU for another MCB.

An alternative would be to supply the RCD shower unit with 10mm² double insulated tails from a henley block.

This was going to be one of my other choices but if I can take a supply from the CU i thought it would be simpler and then i wouldnt have to mess around with the live tails.

 

[holmslaw]

..

 

[ban-all-sheds]

An alternative would be to supply the RCD shower unit with 10mm² double insulated tails from a henley block.

As long as you also install an MCB beside the Henley block, or change the RCD to an RCBO.

Ive just bought a seperate RCD shower unit for a 9.5kw shower as the consuner unit is not RCD protected. It is a 63A 30mA RCD and includes a 50A MCB.

 

[ban-all-sheds]

An alternative would be to supply the RCD shower unit with 10mm² double insulated tails from a henley block.

This was going to be one of my other choices but if I can take a supply from the CU i thought it would be simpler and then i wouldnt have to mess around with the live tails.

Working with live tails is an extraordinarily bad idea, and you can't be advised too strongly not to do it.

The only safe way to add a henley etc is to isolate the entire supply, so if you don't have an isolation switch, either standalone or in the meter then the only answer is to cut the seal on the service fuse and remove it.

Which you should also not attempt yourself.

There is no space in the CU for another MCB.

So you recognise, rightly, that you can't mess with the tails, and you know you don't have space in the CU for another MCB.

How on earth did you think you'd be able to supply the shower unit?

Click me.

 

[alanwheeldon]

sorry i meant there is space in the CU for another MCB but the part i am unsure about is how to wire in the seperate RCD unit to the CU.

Would it be right if the circuit is connected as follows, CU, MCB, RCD, shower switch, shower.

Im just unsure about the RCD location as they are normally before the MCB in the consumer units. Ive never had to wire in a seperate RCD yet for a circuit.

 

[Click-Sure]

I'm going to come in with -

Get a http://www.competantperson.co.uk/ in to do this job.

 

[alanwheeldon]

I believe I am but im not 100% sure on this one, thats why im asking for help

 

[josh1e]

i know this is slightly off topic, but

can anyone install a shower circuit with new RCD from the fusebox fitting a new mcb? i thought this was where a normal person had to then employ an electrician or at minimum a registered competent person?

or if a normal person does it, is it that they are then required to notify it?

thanks