Re: Ceiling fan earth

Matt wrote in message

Dear me, no. The first point is that if your wiring is of such an age that the lighting circuits have no earth, then you ought to be thinking in terms of a complete re-wire before too long.
A temporary solution is to run a separate earth (properly called a 'circuit protective conductor' or CPC) from your fan back to the main earth terminal in your consumer unit or fuse-box (near the meter). A water pipe should not be used as a CPC because (a) you can't rely on its continuity after plumbing alterations (plastic pipes, Speedfit fittings, etc), and (b) in old wiring there's probably no main bonding to the incoming water service in any case.

For a separate earth like this you will need 4mm^2 green & yellow single-core earth wire. The cable type is called 6491X, but just ask for "4 mil earth". You'll find that it has seven strands, not one, BTW.
Strictly speaking, to comply with wiring regs your earth should follow the same path back to the consumer unit as the other wires in the lighting circuit. However that probably won't be a practical thing to do and ignoring it is a much more minor transgression that not having an earth at all.
HTH
--
Andy



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Hmm, that's interesting. My house is a 30's place, but the wiring looks reasonably modern to me (circuit breakers not fuses, etc.) Just how old would wiring be for you to expect lighting circuits to not be earthed?
I can see the ceiling rose has been moved in the room in question, so another possibility is that a new cable was installed for the move, and earth omitted at that point. I'll investigate more closely.
Thanks.. Matt

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It is very easy to replace a consumer unit and accessories. (I just replaced my old fuse box with a modern consumer unit with RCBOs etc. in 3 hours). It is very difficult, expensive, disruptive and time consuming to replace the cabling. You will, therefore, find that consumer units and accessories do not give a good indication of the age of the wiring as they are frequently upgraded to keep up with developments. (i.e. old fuse box replaced with MCBs, then an RCD or RCBOs are added at various times).
Basically, if the lighting circuit has no earth, it is probably pre-1970. If it is made of rubber, instead of plastic, it is probably pre-1965. These are not precise dates, however.
Christian.
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Dave Plowman wrote in message
[4mm^2]

No, not at all. 4 mm^2 is the minimum size for an unprotected CPC which
- is not an integral part of a cable, or - is not formed from metal conduit, trunking, etc., or - is not contained in an enclosure formed by a wiring system.
[Reg. 543-01-01]
It's analogous to the 4mm^2 minimum size for supplementary bonding in bathrooms: size is dictated by the need for mechanical, rather than electrical, robustness.
--
Andy



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You could always run the ceiling fan from a fused connection unit to a nearby ring main. I bet the socket circuits have earthing available.
Christian.
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