trying to sort out our ceiling lights, theres 5 in the kitchen, 3 in bathroom, 2 in toilet, all 12v MR16s (transformer in loft). just moved back into our old house and theres a fair few of these lights out. bought a pack from screwfix, 20W halogens. as im going round trying to replace them tho, some still arent working. im swapping good bulbs round in a process of elimination, and there are 3 sockets that wont light any bulb.
looking at some of the bulbs im taking out, theres a mix of 50W, 25W, and now im putting in 20W into the mix.

is this ok? yes, some will shine brighter than others id say, but could mixing them up have caused any problems with the sockets themselves?

is it a job for a sparky now, or is there anything simple i can look at (once ive knocked the circuit breaker off of course ;-))

i can access the top of the sockets from the loft, they dont have any covers on them, just holes cut into the loft insulation to prevent overheating.

thanks

The transformers can fail. Take a known good lamp and try it in all the fittings to find the duds.

thats what ive done mate thanks. ive found 3 of the 10 are dead sockets this way. i know theres one transformer in the loft, but does each socket have its own transformer then?
and could mixing the wattages have created a problem?

20 watt!! I hope you eat plenty of carrots. 🙂

Seriously thought wouldn’t you be better off with something like 4 watt LED’s?

There can be one transformer per light but sometimes there can be one transformer which can power maybe 4. However, it’s not unknown for people to try and drive more than one light off a transformer designed for one light only.

Take the light out the hole and gently pull the power cable. If you’re lucky the transformer should pull down too. The transformer will have a power rating on it and this will tell you whether it can take the wattage. I would say that 50W is probably fine though.

MR16 and 12v systems are not particularly reliable. If you’ve the space to fit them I’d put in LED GU10 lights in their place.

Rich.

Indeed – replace failed transformers with GU10 LED wherever you’re allowed to. Chop the mains side of the transformer and fit new GU10 tails

Joints should be in a box of some sort.

If you have one transformer supplying multiple lights each output should have it’s own fuse, it’ll be slightly smaller that a plug top fuse and glass so you should be able to see if it’s ruptured or not. The wattage of the lamps should not exceed the VA rating of the transformer, even if you have small individual transformers – they’re usually approx 105VA for the small ones.
Assuming you do have a 12V supply to the downlight the next likely culprit will be the (usually) porcelain round lamp connection part. As the lamps run very hot they don’t last long at all, and can usually be diagnosed as one of the pins on the old lamps will be blackened by arcing. They’re only 12V so not enough “push” on the current to overcome a bad connection.
As others have said, definitely change for LED GU10s. The payback time in a kitchen where they’re often on will be a few months and they’ll last years. It’s a relatively easy swap.

20 watt!! I hope you eat plenty of carrots.

theyre actually quite bright, id be happy if they all worked.

MR16 and 12v systems are not particularly reliable. If you’ve the space to fit them I’d put in LED GU10 lights in their place.

Indeed – replace failed transformers with GU10 LED wherever you’re allowed to. Chop the mains side of the transformer and fit new GU10 tails

Joints should be in a box of some sort.

As others have said, definitely change for LED GU10s

as ever when i get advice on here, ill take it. what are LED GU10s going to give me? cheaper running costs? lower heat? what initial expense for 10 lamps up and running?

im assuming id be doing away with the 12V side of things, so removing the transformer from the equation? would anyone have the time to tell me exactly what i need to do and what parts id need please?

thanks a lot 🙂

As an example I had an email fro LED Hut this morning, 10 5w GU10’s for £21.99.
If all your current lamps where working 10 x 25w (25w is a guestimate) =250w
250w X 24hrs x 366days (this year) @ 10p a unit = £219.60
50w X 24hrs x 366days @ 10p a unit = £43.92
Of course they’re not going to be on all the time but you get the idea.

Replacing mine with GU10s. I shall do this after I track down the electrician who installed the MR16s and thought it was a good idea to box the transformer into the wall and plaster over it, so I can dismember him with his own wire strippers.

**** knows how these people ever got qualified to do their jobs.