Discuss Split MCBs on consumer unit in the Electrical Forum area at ElectriciansForums.net

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Hi all.
How would you split MCBs where there are two ring final circuits (so better separate them). There is one electrical shower (will be on 40A).
Any ideas?
TNS system.

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Bit of a random question. But if it was me I would put shower sockets and lights on one side. And sockets whatever the 16amp breakers for and the other lighting circuit on the other rcd.
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I forgot to add that there is only one circuit for lightning. So that is why I would do like on photo.


Yeah , another advice on topic :)))
There is no RCBO , why would I put RCBO like I have MCB 6 A for light.
If you dont like when i go slightly off topic dobt read it, i was asking where the SPD is, its relevent to the work your doing.

The RCBO is common sense if the house only has 1 lighting circuit to cause minimal disruption to the customer in the event of a fault.

I dont think you should even be fitting a mains board if you have to ask such a basic question such as how to lay out the circuits.


I think I know why the OP has taken the guts out of the board; perhaps he doesn’t want us all to see the cu installation ..
Please take a photo of the consumer unit


Are you DIY? No shame if you are, but an electrician wouldn't need to ask which circuits to put on which side of a CU.


Always put the most power draw next to the main switch. split them like said above! dont install them like you have in the picture though!
you need some spare spaces on both sides of the board.
If there's only one lighting circuit, what's the second 6A MCB?
The split is how I would do it, with the ring on the same side as the shower being the house ring, rather than the kitchen ring. This is to even out the load between the two sides, and is less likely to plunge the house into total darkness if the RCD on the lighting side trips, since there may be table lamps/ TVs on the house ring.
This won't comply with the current regs unless the fuse/cut out supplying this board is rated at no more than 63A. The LH RCD would have to be rated at 80A with a 40A and 32A MCB fed from it.

While on the subject, whose bright idea was it to choose 32A and 63A
as 'standard' ratings. 32A and 64A and you could feed two 32A MCs from a 64A RCD, or similarly two 30A MCBs from a 63A RCD.

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