Hiding tails in wall

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Calling all electricians!

We're having an extension built and before this is done we're having to demolish an existing garage. Our electricity meter, consumer unit etc are all in the garage so will need to be moved.

We're going to get the electicity board to move the meter to the outside front wall of the house and the consumer unit will then go on the inside of that wall. We didn't want to have the cables and tails showing so wanted to have a channel made in the wall and then put them in the wall and then plastered over. But we had an electrician round who said that the tails etc could not be put in the wall but had to be put in trunking on the wall. We don't like the idea of plastic trunking running down the wall on show- is it really true that they can't be hidden in the wall?
 
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In my new extension they run up the cavity into the roofspace and then in trunking along to the CU
 
Tails should not be hidden under plaster. And if they have to go any distance greater than, say, 3 metres, Armoured cable should be used.

Have you recieved a quote from the electricity board yet? :LOL: be prepared for a shock!! :eek:
 
Tails must never be hidden, as it is incredibly dangerous if someone were to drill or nail through them. Ask your electrician about mounting a switchfuse in the meterbox, then running a large T+E or a SWA from the switchfuse to the consumer unit. As this is a submain cable in can be burried in the plaster (providing all regs such as safe-zones etc are adhered to)

Also as far as I am aware the running of cables in a cavity is not permitted for any cables, especially meter tails.
This is due to the fact that there is no way of knowing where the cables run, and some types of cavity wall insulation can react with the PVC cable insulation, and all types of cavity wall insulation will require the cables to be derated by as much as half its rated current carrying capacity.
 
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RF Lighting said:
Tails must never be hidden, as it is incredibly dangerous if someone were to drill or nail through them.

Could you elaborate on this please? If the tails are run in safe zones I can't actually see how nailing into them is any different than nailing into the phase side of a highly fused T&E.

The tails in my house are plastered into the wall (but then again there is quite a bit of questionable stuff here :oops: ), could maybe one day route them on the outside wall in trunking, would need a bloody big drill though, wall is nearly 18" thick!
 
Adam_151 said:
RF Lighting said:
Tails must never be hidden, as it is incredibly dangerous if someone were to drill or nail through them.

Could you elaborate on this please?

Not really :oops: Just the rating and type of fuse i guess.

If the tails are run in safe zones I can't actually see how nailing into them is any different than nailing into the phase side of a highly fused T&E.

There probably isn't much difference TBH, nailing either of them would be very unpleasant.

The tails in my house are plastered into the wall (but then again there is quite a bit of questionable stuff here :oops: ), could maybe one day route them on the outside wall in trunking, would need a b****y big drill though, wall is nearly 18" thick!

Thats nothing. We had a wall 44" inches thick :eek: :eek: that we needed to get through last thursday.
We found a different route in the end. :D
18" is not an unusually thick wall, That is where the old meter long dill bit comes in handy.
 
mozza said:
We're going to get the electicity board to move the meter to the outside front wall of the house and the consumer unit will then go on the inside of that wall.

Correct me if i'm wrong but looking at what you have said here there is no problem in chasing the cables into the wall as long as:

You install the cables in the correct zones

see here http://www.niceic.org.uk/approved/quest3.html
Please Note:
Your electrician may have made a common sense judgment over regulations.
If he could see a likely chance of those cables being damaged then I would say his judgment was correct
I would do the same....
 
crafty1289 Tails should not be hidden under plaster. And if they have to go any distance greater than, say, 3 metres, Armoured cable should be used.



WHAT ???

Why swa cable ? If over 3mtrs de-rate the fuse size not change the cable type
 
tails before your own isolation/overcurrent protection are generally subject to the suppliers rules and the suppliers don't think its a good idea to bury them and most sparkies will probablly agree (though its not afaict any violation of BS7671 as long as they are routed in the safe zones).

the higher the current or voltage rating of the circuit the higher the risk to anyone damaging it. This is why you don't see T&E in sizes above 16mm (and even 16mm is pretty rare), Tails are generally only protected by a high rated (often as high as 100A) and relatively slow blowing fuse, if a drill hits them and doesn't make good contact then there is liable to be a pretty spectacular fireworks display before the service fuse finally blows .

earthed galvanised conduit either burried in the wall or on the outside surface would probablly be the best soloution but it would have to be pretty big (its not advisable to run each tail in a seperate metal conduit due to eddy currents).
 
Geoffito said:
crafty1289 Tails should not be hidden under plaster. And if they have to go any distance greater than, say, 3 metres, Armoured cable should be used.
Why swa cable ? If over 3mtrs de-rate the fuse size not change the cable type
because it looks better, and it is much safer. It can also be buried in a wall out of safe zones. It has to be protected by a switchfuse next to the meter.

Not sure if there is a reg that backs this up, but i know a lot of DNOs wont connect meter tails longer than 3 metres.
 

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