Dual split consumer unit

[alw94]

Hi all,

First post. Completed part P about 6 weeks ago and I'm now practising on a friends renovation - old consumer unit still in place new one alongside, so I'm practising testing on dead circuits. Anyway, my question for now is re. split-load consumer units.

My friend has bought a Wylex split-load unit - 1 x 80A/30mA RCD - 6 protected/6 unprotected. We've split upstairs/downstairs sockets & lights, separate circuits for cooker & boiler and will likely have 6 maybe 7 circuits. He has said that an electrician has told him to put sockets on RCD and lights on other side. Now, this advice seems blatantly incorrect to me as all his circuits need to be RCD protected - due to bathroom/kitchen and shallow depth circuits. So, assuming that I'm correct, can anyone advise on the best way to set up C/U. Adding another RCD doesn't look too easy due to space/tails etc (but maybe I'm not looking at it right). He already has bought C/B's ( 2 x B32, 4 x 6) and the obvious solution to me is either RCBO's to cover any circuits we can't cover with the RCD but due to extra cost is adding another RCD a possibility? I'm suggesting another RCD to avoid tripping all circuits and I'm thinking of alternating upstairs/downstairs circuits but seem to think that RCBO's or another dual protected split load C/U maybe the only practical solution.

Any advice/help would be welcome.

 

[daniel hill]

personally i would put sockets on the rcbo and rest on the rcd as wen plug in faulty items wont trip most of the house only the circuit

 

[Spudnik]

Careful of the Wylex RCBO's as the majority are C type and not b.

 

[alw94]

Many thanks for your replies.

Yes, ok, makes sense. The addition of the rcbo's seemed to me to be the most likely option.

So is the option of another RCD pointless/impossible/impractible?

I guess the difference in cost between 2 rcbo's and an rcd isn't really a consideration.

 

[Spudnik]

You would also need to split the busbar and buy a set of internal tails to form a dual RCD CU.

Better off purchasing a whole CU

 

[alw94]

Yes, either RCBOs or even new C/U are the obvious way forward. Not much difference in cost.

Just out of interest - if we put all circuits on the 1 RCD - this still meets regs right? But just not good practice? As the bus bar is split, it would need a new longer one to fit C/B's on it.

 

[tigerpaul]

A dual RCD board with upstairs lights and downstairs sockets on one side, downstairs lights and upstairs sockets on the other side.

That way, if one side trips, you're not in total darkness because you can plug the table lights in etc...

As I've had pointed out to me in another thread, one RCD covering the entire installation is against the regs. Because then you've got circuits detrimentally affecting the entire installation.