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Ring wiring circuits

wyominpat

Dec 8, 2011
3
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Dec 8, 2011
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It was good to see in a previous post that ring circuits are legal under the NEC. As a Brit living here we moved into a 1970's house, had an electrical survey which said it was all OK then was stunned to find that when the kettle was plugged in and the microwave turned on (on the other side of the room) the breaker tripped. I was more stunned to find the wiring was all Aluminium!

Now back in the UK when I built a large kitchen and worked with the electrician to wire it we had one ring circuit into which the fridge, microwave, kettle and all other work top devices plugged. We had over 8 double sockets on this circuit. The only separate circuits were one for the range and another for the lights. We never had a circuit trip in 12 years. I know we were on 230vac so the amperage was half but even so.

We did get the electrical company who supposedly survey to tail all our circuits with copper tails in Alu>Copper connectors free of charge.

I am now extending the kitchen and installing separate radial circuits for fridge & microwave sounds OK the issue is then if we want to put the fridge somewhere else? or the microwave? Does not give much flexibility. I would like to put in a ring on 10/2awg. It is 10ftx20ft in area.
What do you think?
 

jackorocko

Apr 4, 2010
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Apr 4, 2010
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1,284
First thing I would do is see how much amperage is getting used when you turn on those items and the breaker trips. I have had this issue with 1970's electrical breakers getting weak over time and tripping under light loads. Is that electrical panel a stab-lock?

You also don't need 10awg wire for a 20A circuit. 12/2 Cu is all that is required, When using aluminum you always goes two sizes bigger for the same load on copper. 14/2 for a light circuit w/ 15A breaker.
 

wyominpat

Dec 8, 2011
3
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Dec 8, 2011
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Amperage

Hi Yes a new board was installed with new trips when the service was upgraded to 200 amps. Improved it but did not fix it. Be great to get rid of the old aluminum. In the UK we never had aluminum wiring - ring circuits were introduced after the war because of the shortage of copper and there can be drawbacks but correctly installed the load balancing feature works well.
 

electro_pa

Aug 14, 2011
16
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Aug 14, 2011
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Ring circuit loadings.

Hi wyominpat
UK ring circuits were dependent on fused appliance plugs to protect from overloads. A practice not common in other places. USA & Australia use radial wiring patterns with individual breakers, rated much closer to expected circuit loadings.
The ring-main was supplied with much heavier fuse/breaker to protect over-heating the wires only. Fused plugs protected each appliance/cord assembly.
Not surprising the UK installation did not trip in your experience.
These days, with appliances 'multiplying like rabbits', you just never have enough outlets. Switchboard space soon runs out!
Regards,
Clive.
 

wyominpat

Dec 8, 2011
3
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Dec 8, 2011
Messages
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Ring circuits

Thanks for the reply - yes must appliance plugs in the UK have fuses. It used to be that they were supplied without plugs so people would buy a new device that really needed a 2a fuse but the plug would have a 13a in as standard. They would just fit it and carry on!

The problem with putting radial circuits in is that you may put a 12/2 dedicated for a fridge or a microwave and then 14/3 for random sockets. Then later on the kitchen has new units in so the fridge moves and ends up on a 14/3 circuit. An alternative ring solution for a kitchen( on 115/120VAC) is to put 2 rings in with each ring feeding alternate socket groups. That way you cover that situation with 4 cable runs off 2 x 30a breakers.

Of course in the UK its 230VAC so the ampage is half so a single 13a ring will service a large kitchen on its own.

Interestingly in Saudi it depends which hotel you stay in and who built it - get to your room and you may find either UK style sockets 230v or US120v - or both!
 
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