ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades Hello from the U.K.

Hi everyone:

I'm an engineer in England and came across your board quite by accident a couple of weeks ago.

I have spent time in the States, and although I don't know the details of the NEC, I am familiar with your general wiring practices, etc.

It's really interesting to read your messages and compare the topics and problems being discussed with the sort of problems we run up against here in the U.K.

If anyone is curious about any aspect of how things are done over here, I'd be happy to oblige.

Hi Paul;
tell us a little about wiring methods in the UK please, maybe some differences that you've seen would be interesting.

Paul,

Welcome!
Yes, by all means share with us. I've heard that circuits are connected in a "Ring" How does that work and what are the benefits or downsides in doing that?


Bill

My welcome as well!
I'm quite intrigued with the way things are wired in different places.
Don't you have some sort of fusing at the point of use?

Hi Sparky,

There are so many differences between U.K. and U.S. practice that they could easily fill a book. Here are a few to start you thinking!

You may well know this already, but our standard residential service is 2-wire at 240V, 50 Hz, so all our domestic appliances run on 240V, not a mix of 120 and 240. The neutral is grounded ("earthed" in British terminology) so the hot wire ("live") is a full 240V with respect to ground.

We have completely different types of plugs and sockets, and as you might expect, different standard mounting box sizes etc. Our color code is different, and as anyone who has visited the U.K. will have soon realized, our light switches are up for off, down for on.

There are far more fundamental differences in circuit arrangements. For example, in British homes it's usual for lights to be wired on separate circuits to sockets (receptacles), partly for historical reasons and partly because of the system used to distribute power to wall outlets.

As there are two questions here relating to the latter, I'll try to answer them in a separate post.

Fire away with your 200 follow-up questions.....

Hi Bill & Electure:

Your two posts are somewhat related, so I'll try to answer them together.

Yes, we do have ring circuits and fusing at point of use. The ring arrangement was introduced in the late 1940s. Prior to that we had several different types of plug in use, rated at 2, 5 and 15 amps, all with round pins.

The ring arrangement saw the introduction of a new type of plug which was intended to be a universal connector for portable appliances. A ring circuit is wired from a 30A fuse or breaker at the panel to each socket in turn and back to the panel to complete the ring. All three conductors (live, neutral, earth) are wired in a ring.
30 amps at 240V is a lot of power, so the house fuse is there just to protect the ring wiring. The plug has three rectangular pins and is rated at 13A max. (chosen to allow for a load of up to 3kW). Every 13-amp plug (known officially by Briish Standards as a BS1363 plug) is fitted with a small cartridge fuse, which is available in several different ratings up to the 13A maximum.

Advantages of the ring:

A 30A ring can provide up to 7200W and can serve a large area (up to 1000 sq. ft. for each ring is the accepted limit). Each portable appliance has its own fuse in the plug. Smaller, easier-to-work cable can be used than would otherwise be needed for a 30A branch.

Disadvantages:

Overcurrent protection for the cable relies on the integrity of the ring; a broken live or neutral will still leave all outlets energized, but a dangerous overload could occur. Mr. Joe Public often has no idea what size fuse should be in each plug and runs everything with a 13A fuse "Because it's a 13-amp plug." Adding extra outlets entails more work to maintain the ring. DIY extensions often result in a broken ring or a dangerous spur (spurs are O.K. under certain conditions).

These are some of the main pros and cons put forward frequently. Personally, I'm not that keen on rings and prefer other arrangements.

Over to you...

To say it in plain "English", with the ring, there are two ("parallel") electrical paths to each outlet; therefore, the conductor needs only to be half the ampacity.


Putting light switches in upside down goes along with driving on the wrong side of the road.

But on a serious note, how are the pronga on your receptacles oriented? Do you put them with the earthed conductors up?

Hi,

Yes, the smaller cable which can be used because of the parallel paths is probably the the most widely claimed advantage of the ring.

We only use them for feeding sockets, however, and everything else is wired in the more conventional way.

A typical small older house might have a 30A ring for wall outlets, a 30A branch for a cooker (range), a 15A branch for a water heater (almost always 3kW here) and a 5A branch for lighting.

Most houses these days, and larger or higher budget ones in the past use two 5A lighting circuits and two 30A rings.

As for the switches, I actually prefer the American up for on, down for off! It just seems more natural to me. (Don't mind which side of the road I drive; I'm happy on the left or the right!)

All of our sockets, both the older round-pin types and the newer rectangular-pin ones are arranged with the earth/ground at the top. Neutral is then below it to the left and live/hot to the right.

I've seen U.S. receptacles mounted both ways up. Is there an accepted standard, or is it just a matter of the electrician's preference?

I've seen U.S. receptacles mounted both ways up. Is there an accepted standard, or is it just a matter of the electrician's preference

Paul;
It's actually highly debated, that's why we are curious. So is it a 'code' to install them in the manner you descibe ??

>Neutral is then below it to the left and live/hot to the right.
Those positions are swapped compared the 120 V receptacles.

>Is there an accepted standard, or is it just a matter of the electrician's preference?

It might be someone's preference. Many accessories are laid out assuming that the ground prong will be down. But I personally prefer them up.