Hi- have just spotted in my consumer unit that the kitchen ring mains live leaves one 32A MCB and returns to the 32A MCB next to it. (Looks like wire-clamp holes were full). Not my area atall, but just wondering if this is OK. Would both breakers trip with a fault, or, and may be a stupid question, would they act together like a 64A breaker, and therefore need an electrician to rewire? Thanks.
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Should ring main live return to same MCB?
- Thread starter RRRRRR
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- 19 Jan 2005
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One way to check is to switch off one mcb and check if sockets still live. Switch back on and switch off t'other - if still live then likely. Switch off both to confirm the circuit is dead.... and the two legs are split over the mcbs'
SB
SB
And you're sure it's not 2 radials?
How can they be full? How many wires are in each one?
Thanks for the help folks. Without boring anyone any further, I can see the ring (ceiling down), and as helpfully suggested, yup- still live with one mcb off. Now, how do you correct this (or your friendly Part P electrician) if the live cable to be moved doesn't have any space for it in the one mcb clamp? Whole new consumer unit.......? Seems overkill.....
So you've got 3 ring finals spread over 2 breakers?
You might be able to get 4 conductors into one MCB - try untwisting them?
Once you've established that the mystery circuit is a ring you're going to have to get it sorted, so if you really cannot get 4 conductors into 1 MCB you'll have to add another MCB into the CU, or replace the CU, or put a 2nd one along side it.
If it's a ring you must do something - leaving it as is is not on.
You might be able to get 4 conductors into one MCB - try untwisting them?
Once you've established that the mystery circuit is a ring you're going to have to get it sorted, so if you really cannot get 4 conductors into 1 MCB you'll have to add another MCB into the CU, or replace the CU, or put a 2nd one along side it.
If it's a ring you must do something - leaving it as is is not on.
Yes but I strongly recommend you get someone in, it will only cost a few hours.
If you put the cables in the breakers wrongly you will have a cable rated at 20amps that has a mcb protecting it of 32amps.
Also an electrician might be able to rejib the CU and insert another breaker, and issue you with a certificate and part p etc.
If you put the cables in the breakers wrongly you will have a cable rated at 20amps that has a mcb protecting it of 32amps.
Also an electrician might be able to rejib the CU and insert another breaker, and issue you with a certificate and part p etc.
I'm guessing you are saying there may be a radial circuit of 2.5mm running on a 32A MCB. nothing wrong there, its in the regs
Where? With T+E? It's compliant if it only feeds a single accessory/socket, but nobody's mentioned that as far as I can see.
I thought that a single socket radial on a 32 amp mcb with 2 existing cables carrying a ring was allowed, but a multiple socket radial that could carry a load in excess of the cable rating wasn't.
The issue is simply that a 2.5mm cable cannot carry 32 amp loads, hence why radial 2.5mm is restricted to a 20 amp mcb.
yep
yep
Highlights again the problems of remote diagnostics and assumptions
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