Shower consumer unit

[ptailor]

Hi, people
I have just completed plumbing a 9.5Kw electric shower, I thoughr I could connect straignt into the consumer unit to a 40 Amp MCB, but instruction manual say's I need an RCD in the middle. The supplier of the shower consumer unit quoted me "Part P" and now will not refund my money or tell me how to fit this unit to my consumer unit, could someone help, I don't want to employee an electrican, I don't want to play with live wires, I don't want to pull the service fuse. Could someone please tell me how to connect my shower to the shower consumer unit and then to the main consumer unit.[/i]

 

[ban-all-sheds]

Hi, people
I have just completed plumbing a 9.5Kw electric shower, I thoughr I could connect straignt into the consumer unit to a 40 Amp MCB, but instruction manual say's I need an RCD in the middle.

It's generally reckoned to be a Good Idea...

I don't want to employee an electrican,

Genuine question - do you want to obey the law? You will get the advice you need here regardless, but what you will be advised to do will depend on whether you want to do it legally.

Leaving that aside for now - what cable size have you chosen, and how have you accounted for where it runs and how long it is?

I don't want to play with live wires,

Wise.

I don't want to pull the service fuse.

If you're fitting a separate CU for the shower, you will have to do this, unless you have an isolator built into the meter or between the meter and the existing CU..

Could someone please tell me how to connect my shower to the shower consumer unit and then to the main consumer unit.

If it really is a shower CU, then it should not be fed by the main CU - what would be the point of a second MCB in series with the one in the main CU?

If you have a separate enclosure, and your main CU does not have an RCD, then you could use the enclosure to house an RCD, i.e.

[MAIN CU - 40A MCB]====[ENCLOSURE WITH RCD]===[SHOWER]

I wonder, though, given this last question, if you really know enough to be doing any of this work....

 

[Albert]

Hi, people
I have just completed plumbing a 9.5Kw electric shower, I thoughr I could connect straignt into the consumer unit to a 40 Amp MCB, but instruction manual say's I need an RCD in the middle. The supplier of the shower consumer unit quoted me "Part P" and now will not refund my money or tell me how to fit this unit to my consumer unit, could someone help, I don't want to employee an electrican, I don't want to play with live wires, I don't want to pull the service fuse. Could someone please tell me how to connect my shower to the shower consumer unit and then to the main consumer unit.[/i]

The best thing to my opinion is to use a RCBO, if you don't have a split load consumer unit, the RCBO will do the job of a MCB and RCD at the same time, the problem is that they are more expensive. What cable size are you using, have to be careful and make sure that it can carry at least 41.3A, how did you pass the cable (methode), etc. this are points that you must consider as they will effect the cable and protective device capacity (in A). I would not like to be the bad guy but you should know that adding a new circuit in the consumer unit is, what it is called, a notifiable job, with all that goes with it.

 

[ptailor]

Hi, Ban-All-Sheds
Many thanks for you feedback, the cable I'm using is 10mm and is 12meters in length, running up through stud wall, into ceiling, down inside airing cupboard, emerging at the consumer unit, it's a Hagar consumer unit housing HRD fuse cartridges, this unit does not have an RCD, the shower consumer unit I have has an RCD as well as a 40 Amp MCB in it, this MCB does fit into my consumer unit, therefore could I fit this MCB into my hagar consumer unit take my live from this MCB and Nutral + Earth from the bus bar within the CU into the RCD which I have placed next to the CU as per your sugestion ( ie MCB --to-- RCD ---to--- SHOWER )

 

[ban-all-sheds]

Yup, provided the CU can cope with the new total load - do you know what it's rated at?

If it's OK to go ahead, put the MCB closest to the main switch in the CU.