Bathroom lights and MCB's

Brizlix · 14 Sep 2011

Hello,

My bathroom has an ugly suspended ceiling. Attached to this is currently 3 light fittings. They have a screw on frosted ball which the lightbulb fits inside.

The light fittings are so old that only one of them is working now. The plastic that the bayonet of a lightbulb sits in has broken. I'm therefore, going to replace them. It is possible to get like for like but they are ugly and the wife has never liked them.

I've found a set of halogen spotlights on offer. Bargain bin at a large highstreet DIY retailer. They are suitable for bathrooms and none of the lights will be positioned in any of the Zones. The void between the real ceiling and suspended is at least 300mm so no issues about clearance for the lights.

The instructions for the light say they need a 30ma RCD. All of the lights in our house run off a 5mh MCB. Will I need to replace the MCB due to the new lights?

bernardgreen · 14 Sep 2011

I've found a set of halogen spotlights on offer. Bargain bin at a large highstreet DIY retailer.

"Bargain" and "bin" are words to heed when buying light fittings.

"spot" is the other one.

Brizlix · 14 Sep 2011

Okay, if I buy some full price top quality versions will I need to change the MCB.

Also is it right that the bathroom lights are on the same MCB as the rest of the house?

bernardgreen · 14 Sep 2011

Brizlix said:
Okay, if I buy some full price top quality versions will I need to change the MCB.

MCB and RCD are different functions.

The MCB, if is rated at 6 amps, will be OK to protect against over current that would damage cables but does not detect that current is leaking to earth.

An RCD detects earth leakage currents and turns of the power if the leakage exceeds 30 milli amps. That provides some protection if someone is getting an electric shock where current is leaking through them to earth or pipe work etc but not total protection.

Brizlix said:
Also is it right that the bathroom lights are on the same MCB as the rest of the house?

It is not good practise to have all lights on one MCB or RCD. If one light has a problem and the protective device operates then all lights are out leaving the house in darkness.

Brizlix · 14 Sep 2011

Okay that clears things up a bit.

Is it likely that the master trip switch would be a RCD and then split down onto seperate MCB controlled rings for power, lights, cooker etc?

If so is it okay to connect these lights to the current 6 amps if the main RCD is big enough to cope?

Edit - sorry I'm talkiong nonsense. I don't think my consumer unit has any RCD's on it. It's a bit old.

EFLImpudence · 14 Sep 2011

Brizlix said:
Is it likely that the master trip switch would be a RCD

Could be.
Look on the thread entitled 'consumer unit RCD' - See picture. Do you have a breaker like the one on the left with a test button?

and then split down onto separate MCB controlled rings for power, lights, cooker etc?

Yes, but if the RCD trips power will be cut to all protected MCB circuits.

If so is it okay to connect these lights to the current 6 amps

Yes.

if the main RCD is big enough to cope?

It will be. It doesn't work like that.

I don't think my consumer unit has any RCD's on it. It's a bit old.

You could have a separate RCD fitted next to the CU.

Another thing is to ensure you have an earth wire at the bathroom ceiling, some older properties do not.
If you do not you must not fit a metal light fitting.

Brizlix · 14 Sep 2011

Thank you EFLImpudence.

I'm not at home so gonna have a good look at my CU tonight.

However, the new lights have nowhere to wire an earth wire to?

EFLImpudence · 14 Sep 2011

Brizlix said:
the new lights have nowhere to wire an earth wire to?

They will be alright then.

ban-all-sheds · 14 Sep 2011

Then they don't need an earth. It must not be cut back though - it must be joined in a piece of choc block at each light so that continuity is maintained.

But before you cut lots of holes in your ceiling (what's it made of, BTW?), I'd urge you to think again. Recessed lighting can be OK, but only in large sizes.

The little 2" diameter ones came out of the retail display market, where they were designed to throw small pools of light onto individual items. Ever noticed how a common term for them is spotlights?

They are actually specifically designed to not be any good for providing general room illumination.

I often refer to them as torches, and if you look at the business end of a Maglite you'll see a marked similarity to an MR16 lamp.

In places like kitchens, bathrooms, WCs, possibly hallways and landings where you just want unobtrusive efficient lighting that just gets on and does the job, something like this is ideal:

It's possible to dim that sort of lighting, if that's something you want.

Brizlix · 14 Sep 2011

The ceiling tiles are like what you would find in an 80's office. Dimpled white square things. Horrible.

I reckon I'm probably just gonna replace like for like. The missus will have to put up with the uglyness and we are hoping to move next year.

Thanks everyone for your help though.

ban-all-sheds · 14 Sep 2011

Get rid of the dropped ceiling, make good & decorate, put up some nice-but-not-too-expensive surface lights - there are masses of designs out these apart from the traditional globe.

Definitely do not put in spotlights if you are planning to sell - they are becoming less and less popular. You won't lose a sale because you don't have them - anybody who does want them will look at your bathroom and think "I could put spotlights in there", but you could easily lose a sale if you do have them, as anyone who doesn't want them will look at your bathroom and think "I'll have to replace the ceiling".

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Bathroom lights and MCB's

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