Two ring circuits combined onto a single MCB


Postby sean29 » Sat Oct 03, 2009 6:07 pm

Hi,
I had an extension built approximately 2 years which had new sockets and lights installed by an electrician. Before the extension was built I had downstairs 2 ring circuits. One for the hall, lounge and dining room and other for the kitchen. I recently noticed that all downstairs circuits are now on a single 32 amp MCB (4 wires into a single MCB) and the other MCB is now empty. There is probably nothing wrong with how the electrician combined the 2 ring circuits but I don't understand why he would. I have an electrical test certificate for this work showing it passed with all sockets on the single MCB. The only thing I can think of is that it was a quick way to tap into the existing ring circuit. The only good point I can think of is I now have a free MCB so I could get a new ring circuit installed for the washing machine, dishwasher and dryer as these are fed off a spur which overloads. Can anyone please advise if there is a requirement/regulation why the ring circuits were combined like this and if it is reasonable to have a new ring circuit installed for my kitchen appliances.

Thanks in advance for your answers.
Sean
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Postby kbrownie » Sun Oct 04, 2009 6:05 pm

I'd run the two circuits on their own MCB
KB
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Postby DEEARR2 » Mon Oct 05, 2009 7:50 pm

Definately not an acceptable code of practice, as KB points out, each ring circuit should have its own 32amp breaker. A breaker feeding 2 ring circuits could potentially over heat and cause damage to comsumer unit.

Regulation regarding this could be supplied if required.
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Postby sean29 » Mon Oct 05, 2009 10:50 pm

Thanks for the responses. I was giving this more thought and I suspect what the electrician did was to accidentally connect the dinning room ring to the kitchen ring when he was extending the circuits for the new extension and probably the only way to pass the electrical test was to connect the rings together at the MCB. What a mess! I was reluctant to do anything about it because it passed the electrical test but it sounds like the advice is to have it put back into two ring mains.

Sean
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Postby kbrownie » Tue Oct 06, 2009 9:32 am

Hi Sean29
How has your electrician extended the ring as there are four legs?
To me that means there are two circuits, you can't do this by accident he's test would show it up and only a fool would do this.
When did you have it done?
Have paid?
Can you contact him and ask what it is?
I'd be concerned
KB
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Postby sean29 » Thu Oct 08, 2009 10:11 pm

Hi KB,
How has your electrician extended the ring as there are four legs?
> Yes, well it has 4 phase wires into the single MCB. Turn that MCB off and it turns off all downstairs sockets.

To me that means there are two circuits, you can't do this by accident he's test would show it up and only a fool would do this.
> I have the electrical cert which I had to send in for building regs to pass the extension. It shows all the tests has passed for "All downstairs sockets" on a single circuit.

When did you have it done?
> approx 2 years ago

Have paid?
Can you contact him and ask what it is?
> it was all in the cost of the extension and the builder has done a runner
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Postby kbrownie » Fri Oct 09, 2009 12:20 pm

You have two circuits running off one breaker is that documented on your paperwork?
I can't see hy the electrician didn't terminate one of the circuits in to the spare.
What's marked up on the CU regarding circuit labels?
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Postby sean29 » Sun Oct 11, 2009 7:58 am

No labels on the CU apart from 1,2,3....
Need to get an electrician in.
Thanks for you responses.
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