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Rebalancing between CUs

Former Community Member over 4 years ago

I have two 1991 MK consumer units, each with 12 used MCB slots. It is a big house, and when we bought it, there were three fuse boards, one for each floor.

One of the MK's has loading on it for a cooker (45A MCB, 6mm T&E), an immersion heater (32A MCB, 2.5mm T&E), heat pump (45A MCB, 6mm T&E) and lighting/socket ring mains (6A/32A). The other just has lighting and socket ring mains.

Intuitively I would like a better balance between the two units. Is there any benefit to (say) moving the immersion and/or heat pump on to the less loaded CU.

All CU and circuits appear to operate well.

Final question, can I free up a CU MCB position by using one MCB to serve more than one ring main - ie is that compliant/unwise. The upstairs sockets seldom get used - may be a fan heater occasionally.

0 mapj1 over 4 years ago

Unless the CUs are on different phases or you need to free up space for new work, I'd not be too worried - in a smaller house it would all be on one CU anyway. How are the distribution circuits to the CUs organised in terms of current capacity and fusing and so on ?

Mike.
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0 Chris Pearson over 4 years ago

It sounds to me that those 30 year old CUs are due for replacement. Is there RCD protection within them?
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0 Former Community Member over 4 years ago

They have RCDs and they work currently - both from tests and trips when working on circuits isolated via MCB.
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0 Former Community Member over 4 years ago

Mike, we have a standard 1963 style supply and electricity board main fuse. That has separate feeds with no switching to the CUs. Other than the two 45A MCBs, all the protection is 6A and 32A MCBs.
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Rebalancing between CUs

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