I've just had an electrical check done on my flat, and it's failed. The consumer unit is ancient, with actual fuses, and no RCDs, and the mains sockets don't have earths. Apparently the pipework that holds the cables would have been the earth when originally installed, but owners before me have replaced single sockets with doubles and not properly connected to the piping. So no earths.

The electrician says that it's impractical to chase along/into the walls to do the rewiring, as they are concrete, and this would be about three times more expensive than doing a "surface" job with conduit (which can be made to look "industrial"). The estimate for even the conduit is looking at a few thousand £. (I'm in the UK)

Obviously opinions from strangers on the internet who can't see the property are going to be varied, but I have no practical skills myself.

Does what the electrician is saying at least seem consistent? (It is a small one-bedroom flat in a block that was purpose built in the 1950s or so.)

  • 2
    It sounds like you have conduit in your walls. In the US, at least, the conduit can be used as the grounding path. If that's the case in the UK as well, then, unless the conduit has failed (rusted & no longer a suitable ground), I'd see no reason that things have to be rerun in surface mount conduit. Even if the conduit has failed, it's inside nonflammable concrete, and an electrician should be able to run a distinct ground wire in addition to the other wires already in the wall. I'd suggest a 2nd (and 3rd) opinion and price quote.
    – FreeMan
    May 12, 2021 at 14:08
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    If there is conduit (electrical "pipework") in place already, it is generally possible to re-use that, pulling out old wires and pulling in new if the insulation is degraded on the current wires, at least where it goes to the same places you want things in the new scheme. Obviously your electrician would connect grounds properly. For new locations you would need new conduits, and unless you want to plaster over the concrete (presumably after re-wiring) it probably is rather difficult to chase wires into solid poured concrete, which I take to be your wall material.
    – Ecnerwal
    May 12, 2021 at 14:12
  • Your only question seems to be about relative cost. Is that what you're asking? If not, maybe revise to be more clear (including your title).
    – isherwood
    May 12, 2021 at 15:39
  • Having conduit in walls would be a fairly simple rewire for a home of that age(at least in the US) the existing wire could be used to pull a new set of wires in. if you wanted to be extra safe use the wires to pull a pull string in as pull string has several hundred pounds more strength than old wires. The code for fill here in the us is basically the same and I bet your code is similar this far back. Rigid conduit would have been the most common method back then or was here for multi family dwellings. I agree with freeman get more quotes. As long as splices in pipe are not allowed add a gnd
    – Ed Beal
    May 12, 2021 at 16:48
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    All of the above comments can be the answer the OP is looking for. Why not move it to the answer box to close out this thread!
    – r13
    May 12, 2021 at 22:47

1 Answer 1


I would focus on replacing the consumer unit.

Once you have RCDs (or better: RCBOs per circuit), the state of the wiring becomes less critical.

As far as earths, the fact that your wiring was done inside pipes (conduits) is very important. Generally the pipes are installed before the wires are, so it's no trouble installing additional wires (or pulling all the old wires out and replacing with state-of-the-art wires).

Carrying earth on the metal pipe is perfectly fine. Or, a yellow/green earth wire can be pulled into the pipe. Either way is fine.

In fact, the old way of using metal conduits is superior to modern methods. They stopped doing them because new ways are cheaper.

So my advice is to make the most out of the existing conduit in the wall. A variety of surface conduit methods can be used for new outlet locations not currently in the piping network.

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