ECN Electrical Forum
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Ring continuity checker.

Maybe have two seperate terminals on the load side of the breaker, one for each end of the ring. If the demand difference exceeds a certain amount - or if any one side exceeds 20A (for 2.5sq.mm twin+E) then trip. Sorts out broken rings and inbalanced loads.

Interesting idea Hutch, but it would need to be a double pole device with similar tests on the neutral to be fully effective.

Our newest members might like to look back at these threads where we have discussed rings in the past: www.electrical-contractor.net/ubb/Forum9/HTML/000004.html www.electrical-contractor.net/ubb/Forum9/HTML/000031.html

The "trunked" system mentioned in an earlier post was sometimes used in old buildings here. It's a similar idea, in some ways, to a ring main. Long gone though.

Consumer Unit (small number of high rated diazed fuses) feeding:

Very heavy radial cables that fed zones (similar diameter to cooker circuits.. 40-50amps)

Each room in a zone had a little fuse box (consumer unit) at ceiling level (usually consealed very neatly) with a small number of diazed fuses on a board inside serving lights, sockets (usually schuko or sometimes BS546) and occasionally individual fuses for fixed appliences like heaters.. It avoided having to run endless cables back to the consumer unit and I guess it was useful when wiring big old georgian and victorian houses that never had electricity and would have used gas lighting until the 1920s and 30s and even later in some cases!

It's actually quite a neat system, often metal ducting for cables followed the same routes as the gas pipes they replaced. This old pipework consisted of larger trunks tapped off to lights and heaters with small feeder pipes.. (a bit like spurs)

(Gas lights were still in fairly common use as late as the 1950s!)

I presume this system was used elsewhere?

[This message has been edited by djk (edited 05-18-2003).]

I've seen the sub-panel system like this on several rambling old Victorian houses in this area.

The layout wouldn't have been designed that way from the outset. It's just that the places have had wiring extended over the years and with the solid brick wall construction a single big sub-feeder to a particular area was probably the easiest way to do it.

One house I worked on a couple of years back in Cromer had an assortment of "fuse boxes" all over the house. It was a huge Victorian house that had been used as a guest-house in more recent times. I kept finding small panels tucked away all over the place, some fairly new, others dating back to the 1930s.

You can do quite a bit of detective work in these places and trace what must have been done. In a cupboard under the stairs was a small 4-way fuse panel below which I found the chopped off remains of what had obviously been the original service to the house. The "new" service entered in an extension which had been built at the rear, and this old 4-way panel had then just had a sub-feed run in from the new position.

At that "new" service entrance, extra circuits had clearly been added piecemeal over the years. There were no less than four separate 4-way panels there, and they were all daisychained! When somebody needed extra circuits, they had obviously just fitted another 4-way panel and then used an existing branch fuse as the sub-feed for it. Move the original circuit from that fuse onto the new panel, and "Voila!" Three extra spare fuse positions!

There were 13A sockets and even a whole panel, if I recall correctly, run on 5A fuses! Some outlets must have run through about 6 or 8 daisychained panels!

The distribution was an absolute mess. In the end I got it down to a main panel at the service entrance, a sub-panel under the stairs for the downstaits and another sub-panel for the upstairs section.


[This message has been edited by pauluk (edited 05-20-2003).]

The ones I've seen were generally quite ok. Highly structured and all installed to a high standard.

The fuse boxes were always Diazed never re-wirable. Nice little panels that fitted neatly into the plasterwork with a door on the front. These were the "posher" houses occupied by the snootier members of society so they had to look the part.

The fittings were usually nice brass tumbler switches mounted on carved teak plinths and the sucho sockets were recessed into similar plinths.

Usually 5/10 amp.. 16 amp was relatively rare other than for specific items like kettles, washing machines etc.