One aspect of the modern ring-circuit usage that I find curious is the apparent lack of thought that goes into planning them in many cases.

The days of wiring with only one ring for the whole house might be behind us now, but how many times do you see two rings, one for each floor? In the average house that means that the upstairs ring is feeding nothing more than a few low-power devices such as electric blankets, radios, bedside lamps etc. while the downstairs ring still has all the heavy loads on it.

Note for our American friends: There is no specific requirement here to run washing machines, dryers, etc. on dedicated circuits. That means that they often end up connected to a general-purpose ring circuit.

Lip-service is paid to the modern increase in kitchen appliances, and I've seen suggestions that this could make it appropriate to run an entirely separate ring to supply the kitchen. If you do that, you still have all the heavy kitchen loads on one ring, but then you have two other rings only lightly loaded (probably not even any heaters in a modern centrally-heated house).

Dave,
The cramped boxes are one of my frequent compaints about typical British wiring. American methods are far superior in this respect.

On the 120 vs. 240V issue, I think the U.S. probably has the best of both worlds: You have 240 available for heavy loads, but with the advantage that no point is over 120V to ground, making it that much harder for somebody to get zapped at the full 240V.

All of us in Britain grew up with supplies of 240V (or thereabouts) to ground, so I guess we don't really consider the higher potential too a big deal. It can kick though! The worst shock I recall ever getting was when I was about 13 and a holder on a chain of fairy lights disintegrated as I was holding it. One wire came off the center contact of the holder, leaving me with the end of the wire in one hand and the shell of the holder in the other. 240 hand-to-hand isn't pleasant! [Linked Image]

Alan,
I understand your feelings about the 2.5 conductors in our cramped boxes perfectly. It's bad enough when you get two sets of cables on a ring passing through a 1" box, but if you find one where there's a third spur cable as well, it's incredibly tight. As Dave hinted, this is one area where I think the American methods are far superior to ours.

You mentioned 4mm being that much easier to work as its stranded. Can I also assume that you preferred the old 7/.029 over the mdoern 2.5 sq. mm for the same reason? Even though the overall diameter of the 7/.029 is slightly larger, I find it much easier to work with in old systems.

On the radial circuit issue in the States, I don't think the NEC sets any specific limit on the number of outlets per circuit. They have dedicated circuits for all large appliances, then at least two 20A "small appliance" branch circuits feeding kitchen/dining area outlets.

Everything else (receptacles and lights) is then wired on general-purpose 15 or 20A circuits on the basis of allowing a minimum 3 watts per sq. foot (residential).