UK wiring style

[102 Inspector]

Just inspected a job done by a gentleman from the UK. The circuits were run from the overcurrent device to a receptacle, then looped through 6 more recectacles than returned to the overcurrent device effectively creating a loop of the current carrying conductor. He did the same thing with the grounded conductor. It did not pop the breaker, but I refused it based on the NEC. I told him I would get code sections if needed and am just starting to dig into the specifics. What is the thought process behind this? Is it because the UK operates from a 240 volt system typically. He was not happy with me since he says it works just fine.

 

[iceworm]

...The circuits were run from the overcurrent device to a receptacle, then looped through 6 more recectacles than returned to the overcurrent device effectively creating a loop of the current carrying conductor. He did the same thing with the grounded conductor. It did not pop the breaker, ....

That's good. No reason it should have.

... but I refused it based on the NEC. I told him I would get code sections if needed .

I'm curious what the applicable code sections are.

What is the thought process behind this? Is it because the UK operates from a 240 volt system typically. ...

I don't know any reason why one would want to do this. I don't know any science or physics that makes it unsafe. There is nothing I know of about the Brit 240V system that changes that.

.... He was not happy with me. ...

No surprise there. You reject his work and you can't tell him why.

Even so, isn't it is a pretty easy fix. He goes out halfway along the string, and disconnects and caps one end of the loop. Unless there is more to the story, there isn't any money here.

ice

 

[qcroanoke]

Just inspected a job done by a gentleman from the UK. The circuits were run from the overcurrent device to a receptacle, then looped through 6 more recectacles than returned to the overcurrent device effectively creating a loop of the current carrying conductor. He did the same thing with the grounded conductor. It did not pop the breaker, but I refused it based on the NEC. I told him I would get code sections if needed and am just starting to dig into the specifics. What is the thought process behind this? Is it because the UK operates from a 240 volt system typically. He was not happy with me since he says it works just fine.

Here is an explanation off of wiki
In electricity supply, a ring final circuit or ring circuit (often called a ring main or informally a ring) is an electrical wiring technique developed and primarily used in the United Kingdom. This design enables the use of smaller-diameter wire than would be used in a radial circuit of equivalent total current. Appliances connected to sockets on a ring circuit are individually protected by a fused plug
Ideally, the ring circuit acts like two radial circuits proceeding in opposite directions around the ring, the dividing point between them dependent on the distribution of load in the ring. If the load is evenly split across the two directions, the current in each direction is half of the total, allowing the use of wire with half the current-carrying capacity. In practice, the load does not always split evenly, so thicker wire is used.

Broadgage will be along to give a better explanation later.

 

[iceworm]

Here is an explanation off of wiki
This design enables the use of smaller-diameter wire than would be used in a radial circuit of equivalent total current. ...

... Unless there is more to the story, there isn't any money here.

Now, using smaller wire than the CB is rated for, would definitely be a case of "more to the story". Did that happen?

ice

 

[tom baker]

Its a violation of the NEC as conductors smaller than 1/0 are not allowed in parallel.

 

[qcroanoke]

Its a violation of the NEC as conductors smaller than 1/0 are not allowed in parallel.

I don't think anything is paralleled. Wire is ran from the breaker through the receptacles and back to the breaker.

For what it's worth I think I've seen this discussed here before.

 

[tom baker]

I don't think anything is paralleled. Wire is ran from the breaker through the receptacles and back to the breaker.

For what it's worth I think I've seen this discussed here before.

Then what NEC section allows the UK wiring practice?
I would say with respect, that there is a difference between "I think" and "I know". Mike Holt will make this comment at his classes, he wants you to know the code.

 

[ronaldrc]

I think it has something to do with voltage drop.

By feeding both ends of the circuit this way eliminates the voltage
drop between the first receptacle and the ones on the load side.

I use to see old timers do this with door bell circuits.

I guess the minimum parallel code would make this illegal.

Ronald

 

[K8MHZ]

Then what NEC section allows the UK wiring practice?

Every one that doesn't prohibit it.

Where is it in the NEC that says it's against code to do it the 'UK' way?

 

[lavacano]

I do not believe any codes were broken in this installation. One thing to look out for however is if it circuit breakers are rated the land two wires under their lug. If they are not then he could accomplish the same effect by having one wire coming out of the circuit breaker and wire not that into the two lines.

I would say if he wants to run twice as much copper for his home runs and the wires are still rated at the circuit breaker current Let him.

Another thing that you might be thinking in his mind in the future to do though is turning some of these outlets into 240 V. In which case this installation of a multi wire branch circuit George Briverai you are 40 V I would not be allowed

 

[K8MHZ]

I think it has something to do with voltage drop.

By feeding both ends of the circuit this way eliminates the voltage
drop between the first receptacle and the ones on the load side.

I use to see old timers do this with door bell circuits.

I guess the minimum parallel code would make this illegal.

Ronald

But a ring circuit is not the same as parallel conductors.

Unless there was only one outlet.

 

[Smart $]

But a ring circuit is not the same as parallel conductors.

Unless there was only one outlet.

Disallowed by 300.3(B), conductors of the same circuit in same raceway, cable, etc.?

 

[ronaldrc]

But a ring circuit is not the same as parallel conductors.

Unless there was only one outlet.

Thanks your'e right, just pointing to what I thought
the logic was behind it.

Ronald

 

[102 Inspector]

Wow, you guys jumped right on this one and gave me alot to think about and go back and review. I should have said when I refused it, I meant I did not accept it and that is why I was looking to review the code. Unfortunately I am not old enough to remember the old-timers way and certianly not rich enough to go to the UK to observe their wiring practice. I will gladly go back and eat crow after all the comments and code search. The breakers are rated for 2 conductors so it starts out okay. this is totally new to me.

 

[qcroanoke]

Wow, you guys jumped right on this one and gave me alot to think about and go back and review. I should have said when I refused it, I meant I did not accept it and that is why I was looking to review the code. Unfortunately I am not old enough to remember the old-timers way and certianly not rich enough to go to the UK to observe their wiring practice. I will gladly go back and eat crow after all the comments and code search. The breakers are rated for 2 conductors so it starts out okay. this is totally new to me.

Keep your eyes on this thread. Broadgage is a member here who lives in the U.K. and I know he will have some input to help you understand what a ring circuit is.

 

[hillbilly1]

A ring circuit is paralleling the conductors, replace the devices with wire nuts, what do you have? A parallel circuit. The device is just an expensive wire nut. Will any harm come from this? No, but it is still paralleling as the current drawn from the middle device will flow back equally on both wires to the source.

 

[ronaldrc]

Wow, you guys jumped right on this one and gave me alot to think about and go back and review. I should have said when I refused it, I meant I did not accept it and that is why I was looking to review the code. Unfortunately I am not old enough to remember the old-timers way and certianly not rich enough to go to the UK to observe their wiring practice. I will gladly go back and eat crow after all the comments and code search. The breakers are rated for 2 conductors so it starts out okay. this is totally new to me.

I am a 1.5 times a old timer.

Please don't eat crow because of what I posted.

And what I said was just the reason he might have did it this way.

I never did have a situation that required me to, even think of doing a
ring circuit.

But if I had I believe my inspector would have turned it down.

That's your call.

Ronald

 

[dicklaxt]

This is called a Ring Loop branch circuit.It is quite common to see in service on offshore rigs in the living quarters and I have seen it done on the deck receptacles as well.It stemmed (so I was told) from a safety standpoint, when a fire or mishap on the rig severs the circuit you can have a functioning circuit in a short time....

dick

 

[Cavie]

All I see a a waste of good copper wire. We used to do that with telephone wires. If the line got cut you could refeed it. It would't be paralell because you didn't stop both wires at the same place. You just brought a wire back frome the last device in the circuit back to the breaker. I'm assuming he did it with the neutral also???? Not a bad idea. If the wire was cut or shorted, just cut out the bad spot and turn the breaker back on

 

[Besoeker]

The circuit is defined in BS7671 as a ring final circuit. "A final circuit arranged in the form of a ring and connected to a single point of supply."
It's fairly common here.