2 Dec 2020
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United Kingdom
Hi, long time reader, but first time asking. Hopefully this hasn't been asked before.

So, currently in the process of giving the bathroom a makeover. I have a 110/240v shaver socket I want to get rid of and I want to install an illuminated mirror (zone 2).

Currently, the shaver socket is fed by two "twin and earth" cables, connected to the lighting circuit, one for the 110v outlet, the other for the 240v.

My plan is to disconnect the shaver socket. I would then terminate one of the cables in a terminal block and leave in the backbox of the old shaver socket. The other cable, I would run back out of the backbox and behind the wall to the back of the new mirror. I then planned to cover the backbox with a low profile chrome blanking plate.

1) Is this allowed / safe / compliant with regs?
2) What are the rules on covering the blanking plate with the electrical mirror. I understand covering a blanking plate, switch or socket with a non-electrical item is a big "no-no" as you are essentially hiding live wires in the wall. However, as this mirror is electrical, I wonder if this is different?

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The issue here is those 2 cables would be connected to an 'isolating transformer' somewhere. If it's not on the back of the shaver socket, where is it? You don't really want to be connecting to the 240 side of this transformer.

I had assumed that the transformer was part of the socket, see photo. I have had the floorboards in the loft up recently and didn't see anything out of the ordinary. Not sure where else to look.


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Oooohkay. Yes it is part of that socket (The big blue lump) The 2 wires are NOT 110/240, They are the same line voltage at 240, and they pass through along to the next light/fan/whatever. They look a big thick to be a part of a lighting circuit (Need confirming) But you would keep them joined together (both browns together and both blues together) and maybe some junction box or Wago connecter to tap into the new mirror.
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Good news.

Blonde moment there. Of course they are feed and return (to the next thing in the circuit). Don't know why I had it in my head that one was feeding the 240 side and the other feeding the 110.

On inspection, these are 2.5 mm cables, not the standard 1/1.5mm used for lighting. I guess its been wired into the socket ring. Hopefully not a problem.
It won't be a problem. This could still be a radial circuit with no return. At least you know what you're doing now ;) Doe's this new mirror have a power supply for LED lighting or mains lamps? You may need to fuse down. 2.5mm suggests a 20A breaker.

Could even be on 32A if it is indeed A RING FINAL.
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New mirror is LED. So I guess I am going to have to fuse down. Moving slightly outside of my comfort zone but happy to give it a try.
Not a huge amount of clearance. Switched spur probably not an option
Some sort of inline fuse is all I can think of, like the ones used in automotive. Or fused spur in the loft from lighting circuit and drop a cable down. As for the blanking plate, If it's screwed to the wall, It WILL be accessible. Otherwise its maintenance free Wago.
fed by two "twin and earth" cables, connected to the lighting circuit

I guess its been wired into the socket ring

Don't guess.

Turn off the breakers in the consumer unit, one at a time, and see for a fact which circuit ACTUALLY feeds this outlet.

If the supply is fed from the lighting circuit, which is doubtless fused at 5A or 6A, then no additional fuse is needed.

If necessary, you can put an FCU at the top of the bathrooom wall, against the ceiling, at the point where the cable comes down.
Success. Its fed from the lighting circuit. Confirmed.

However, the cables feeding the shaver socket are definitely 2.5mm, which seems odd. I thought anything on a lighting circuit would be 1/1.5?

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