new consumer units

[johnnymac]

Hi I know im being lazy and should go get the regs out but its cold out side and its in my van. Can anyone tell me if new con units installed have to be dual rcd or can they just be single???(main switch) cheers.

 

[steptoe]

headbang

is this a real question?

and its not in the student zone?

I suppose if its only 1 circuit then a single RCD would be OK.

what sort of earthing system is it?

 

[johnnymac]

its tncs. theres 4 con sumer units that want changing in a large house, all with only 3 0r 4 circuits in each. the smallest dual board i can find is 5 and 4

 

[steptoe]

so why dont you put one large unit in then?

 

[johnnymac]

not being rewired just boards changed. all in different rooms. ONE MAIN BOARD FEEDING 3 SUB BOARDS

 

[steptoe]

its down to how you want to interpet the regs then,

personally I think in this situation RCBOs may be your best bet,

what does your boss suggest?

 

[johnnymac]

need to keep cost down

 

[M107]

+1 RCBO's

 

[steptoe]

its down to how you want to interpet the regs then,personally I think in this situation RCBOs may be your best bet,

what does your boss suggest?

cost is not an issue according to EAWR,

how does your boss suggest you do this,?

then we might be able to get somewhere with a different idea

 

[johnnymac]

so do you have to have a dual rcd board???

 

[steptoe]

NO,

what does your boss say to fit?

then we can give you some options to work around

 

[M107]

You could

1. Use main switch + rcbo's
   
2. Use split load board with rcbo's & rcd + mcb's
   
3. Use dual rcd board + mcb's
   

Or you could go to your van & look up the regs

 

[johnnymac]

he says would like to fit single rcd main switch boards

 

[steptoe]

well he would be in non compliance of the regs most likely.

but if he is signing it off then you have nothing to worry about,

just do as he says

 

[johnnymac]

electrical genius

 

[Doc Hudson]

headbang is this a real question?

and its not in the student zone?

I suppose if its only 1 circuit then a single RCD would be OK.

what sort of earthing system is it?

I have move it to the student zone as you suggest it is rather basic and I would expect any electrician competent to change CU's to know this information with or without a copy of BS7671 to hand.

Doc H.

 

[sellers]

Every job is situation specific without being theres its hard to call whats right and whats wrong, and even then its how I interpret the regs.

If you look at your typical dual RCD board in domestic for example, on RCD1 - UP Lights, Down Sockets, Cooker and on RCD2 - Down lights, up sockets and kitchen sockets.

Now then look at your situation, if you went for single RCD boards and had DB1 - Front lights, front sockets and boiler DB2 - Kitchen lights, kitchen sockets and cooker DB3 Up lights, Up sockets, shower

I would say it may well be acceptable, you have to take it on you own head if you think it has been designed to minimise inconveinience.

 

[Robin Spark]

If the present consumer units are all in different rooms, then what type of cable is the sub main and installation method? If buried t&e then has your boss thought about 30ma protection for this and how he is going to provide discrimination for the final circuits?