Heated mirror connections...

[Sparks]

I will be installing a heated mirror in the bathroom.

It is simply one of these stuck to the back of the mirror.

am planning on tilling the mirror into the wall (so the mirror is installed, then tiled around, endng up in a flush mirror.

The mirror, of course, cant be removed without destruction.

How do I make the connections behind the mirror? (The cable attached to the heater looks to be very sort, if it turns out to be longer, this won't be a problem!)

Can I sink in a metal back box, crimp the connections in here, install a metal blanking plate like this over the box (Do I need to?)

stick the mirror to the wall, never to see the box again?

I assume I will have to install metal capping over the cable, as there won't be a visible accessory and it will be plaster deep) (the cable will go straight up into the ceiling)

Thanks again! :-)

[PJ]

Specification states that the cable is 1 metre long.

[Sparks]

Okay, I didn't see that before, thanks.

I expect I can take the cable down into the vanity unit, then back up again into the loft, under some metal capping, or up to the loft, in the corner of the room (I don't need capping here do I, I can just bury it in the plaster?

Sorted :-)

Sparks...

[Andy Wade]

Since you'll need a control switch why not take the flex into a single-gang flush box fitted with a DP switch (or switched FCU if the feed is from ring circuit)? Then you've got a visible accessory and can run upwards without impact protection. This assumes the switch will be in Zone 3. This box will also provide a convenient point at which to connect the supplementary bonding, if there isn't already a nearby connection to the earth of the circuit concerned.

If your cable run has no visible accessory then capping is NOT acceptable impact protection. You'd need earthed steel conduit, or a concentric cable (FP200 or similar) or to bury the cable at >50 mm below the wall surface.

[Sparks]

Not really happy with this - it would be the only accessory on the bathroom wall. (Shaver socket it going in the vanity unit, and we have a pull switch for the light)

This mirror heater is connected to the lighting circuit (6A MCB) I will put a FCU in the vanity unit, then take the cable up to the loft via the corner of the room (I can just bury the cable in plaster here, can't I?)

Okay, I think I will just bury it at >50mm between the mirror and the vanity unit then, It's going on a 9" brick wall, so this should be easy once I get my chasing machine!

One other question, I will be installing my shower pump in the loft - I don't need to be able to isolate this from the bathroom do I? (I was planning to install a DP FCU near it, in the loft, fed from the 20A radial I have up there)

Thanks!

Sparks...

[Andy Wade]

OK. I'm not a fan of hiding switches in cupboards but there's no need for emergency switching in this case so I suppose it's OK. You'll need to keep the switch reasonably accessible - that mirror pad is 65 watts and I assume you won't want to leave it on all the time.

Just a switch will suffice. One with a neon might be a good idea to remind you that the thing is on.

If the switch is on the wall inside the cupboard and you have a straight vertical run up to the mirror and a horizontal run to the corner safe zone then there's no need for deep burial. You'll still need to sink a box behind the mirror to connect the flex tail from the pad to the permanent wiring; as you said at the outset this connection will need to be crimped since it ends up inaccessible.

That's OK. You will need a supplementary bond between the CPCs of the pump and lighting circuits and it sounds as if this would be a good place to do it - bond (4mm^2) between the earth terminal of the pump isolator and the lighting circuit earth in the junction box that you'll need to feed the lighting drop down to the shaver point and mirror.

[Sparks]

No, it will be connected to the light switch, so it is only on when the lights are.

Okay.

Okay, I thought the fact the accessory, although on the wall, was hidden from view meant that it diodnt count.

I think the tail on the heater will be long enough to drop down to the switch in the cupboard, so I won't need to bother with this :-)

Okay - even though all the pipework is plastic?

Thanks again!

Sparks...

[Andy Wade]

Doh, I didn't think of that.

The regulation concerned doesn't actually include the word visible...

This isn't good practice. What happens if the pad fails and has to be replaced? If you plaster the flex tail into the wall it will be quite a disruptive replacement! You could put a length of 20 mm PVC conduit in the wall and drop the tail down through that.

Yes, unless all the lights, shaver point, mirror pad and all associated wiring accessories are beyond the Zones.