lighting circuit help

[cando]

been in my house for about 5 months and i am having problems with my livingroom + kitchen lights.

they both have 3 downlights in each room the kitchen ones are screw in lights 240v 40w h2 bulbs i now that much because i have bought god nows how many replacements for them.

the living room are transformer 240v/12v 105va,35w manufactured by ring i know this because the box was left in one of the rooms the problem with living room lights is that after a wyle of being on they dim then go off completely and after a short time come back on again or just switch off completely.

the kitchen and livingroom are both on two different circuits i checked this by switching them on and then turning off the mains and removing the fuses one by one and switching the power back

i live in a block off flats on the bottom and i am not sure if there is enough space in the ceiling cavity for the kitchen lights when replacing the bulbs you can see that there is about 10mm of space between the floor boards of the flat above and the light fitting.

the living room problem has only just started to happen but the kitchen has always been a problem from day one i had to get some bulbs only to have to replace at least one bulb a month from then on.

questions-

is there a recommend hight for the ceiling cavity from the top of the fitting to the floor above?

shoud i think about replacing the fitting rather than the bulbs?

the living room light are only about 8 months old the receipt was in the box to.

could it be that the living room transformer is on its way out and should i replace that to?


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[dingbat]

Sounds like thermal problems in both cases. Low cost replacement bulbs are generally a false economy and quality bulbs may help, but you might want to investigate replacing the lights themselves with GU10 fittings using low heat output, energy saving compact fluorescent spotlights.

Your living room ones sound like the transformer's thermal cutout is operating. And in any case the transformer is being loaded to its limit. Ring, eh? They bought a cheap set from B & Q then. Downlighters are NOT a cheap option - fitted correctly they may well need individual transformers and intumescent fire hoods, which will add £15-25 for each light! (plus labour).

Downlights are genarally a bad idea in flats, especially if there is thermal insulation between floors. (And three doesn't sound anywhere near enough for a living room.) Clearance around the back and top of the lamp fitting can be critical and many fittings come with instructions specifying how much.

 

[cando]

Sounds like thermal problems in both cases. Low cost replacement bulbs are generally a false economy and quality bulbs may help, but you might want to investigate replacing the lights themselves with GU10 fittings using low heat output, energy saving compact fluorescent spotlights.

Your living room ones sound like the transformer's thermal cutout is operating. And in any case the transformer is being loaded to its limit. Ring, eh? They bought a cheap set from B & Q then. Downlighters are NOT a cheap option - fitted correctly they may well need individual transformers and intumescent fire hoods, which will add £15-25 for each light! (plus labour).

Downlights are genarally a bad idea in flats, especially if there is thermal insulation between floors. (And three doesn't sound anywhere near enough for a living room.) Clearance around the back and top of the lamp fitting can be critical and many fittings come with instructions specifying how much.

on further inspection of the living room lights the connector from the transformer to the lights ie after the transformer in the circuit the blue wire is fried and has melted the connector could this be a sign of a faulty transformer or dodgy wiring.

the light fittings that you mentioned GU10 fittings can you tell me where is a good place to buy these and how much they are likely to cost thanks for your quick response the living room ones do not work at all now.

the three are enough for the size of the room with additional side lamps.

also there is no ceiling rose all the wires are connected with wire connectors is this correct or should there be a junction box in there.

 

[dingbat]

Although the voltage on the secondary side of the transformer is around twenty times lower than the primary (supply) side, the current is around twenty times higher. It's the current that generates the heat, which is another reason why insulation around ELV lighting is a bad thing. But it could also be a damaged transformer. Either way, as you now know, it needs replacing. For the DIY-er, mains lighting is easier to install.

Read the 'For Reference' post at the top of the Electrics UK forum (the one with the 'sticky' icon) to see how lighting circuits work. You'll need to figure out where your original circuit wiring goes to - probably the downlighter nearest the center of the room - then work from there. There should be no exposed connector blocks, and taping up doesn't count - all the connections should be made inside accessible enclosures. A ceiling rose is a perfect example of an accessible junction box, but in your case the best bet is to use Choc Boxes, as they are small enough to pass through the downlighter holes.

GU10 is just about the most used mains downlighter fitting. You can buy them almost anywhere. But try here to see a big range of GU10 light fittings and then here to see an example of a compact fluorescent replacement lamp. You can also get LED GU10 lamps - do an internet search.

 

[cando]

Although the voltage on the secondary side of the transformer is around twenty times lower than the primary (supply) side, the current is around twenty times higher. It's the current that generates the heat, which is another reason why insulation around ELV lighting is a bad thing. But it could also be a damaged transformer. Either way, as you now know, it needs replacing. For the DIY-er, mains lighting is easier to install.

Read the 'For Reference' post at the top of the Electrics UK forum (the one with the 'sticky' icon) to see how lighting circuits work. You'll need to figure out where your original circuit wiring goes to - probably the downlighter nearest the center of the room - then work from there. There should be no exposed connector blocks, and taping up doesn't count - all the connections should be made inside accessible enclosures. A ceiling rose is a perfect example of an accessible junction box, but in your case the best bet is to use Choc Boxes, as they are small enough to pass through the downlighter holes.

GU10 is just about the most used mains downlighter fitting. You can buy them almost anywhere. But try here to see a big range of GU10 light fittings and then here to see an example of a compact fluorescent replacement lamp. You can also get LED GU10 lamps - do an internet search.

i have further inspected the lights at the switch only to find that the earth that connects to the metal box in the wall is live to. this surely cant be normal. tested it with a mains tester screw driver and the light on the end lit up.

there is no insulation in the space between floor above and the ceiling.

 

[dingbat]

Throw away your mains tester screwdriver. It's a potentially dangerous piece of equipment and doesn't tell you anything useful. It's not unusual for an induced voltage to be present on conductors that lie parallel to phase conductors, but you need to do some more testing to be sure your circuit is actually okay. If your circuit protective conductor ('earth') is actually at a dangerous potential then the fuse/circuit breaker should have operated, but it won't do this unless it is continuous back to the main earth terminal

Ideally you should be able to conduct an insulation resistance test but the kit for that is pricey. You can, however, go a long way with a relatively cheap multimeter, which is a useful addition to any household toolkit. With one, you can check for continuity of all conductors and for, at least, a high resistance between all conductors. Obvious faults will be picked up, if not accurately quantified. If this doesn't sound within your capabilities maybe you'd be best swallowing your pride and calling in an electrician. We don't bite and we don't always cost the earth! (And ninety percent of our daily callouts are to lighting jobs.)

 

[cando]

Throw away your mains tester screwdriver. It's a potentially dangerous piece of equipment and doesn't tell you anything useful. It's not unusual for an induced voltage to be present on conductors that lie parallel to phase conductors, but you need to do some more testing to be sure your circuit is actually okay. If your circuit protective conductor ('earth') is actually at a dangerous potential then the fuse/circuit breaker should have operated, but it won't do this unless it is continuous back to the main earth terminal

Ideally you should be able to conduct an insulation resistance test but the kit for that is pricey. You can, however, go a long way with a relatively cheap multimeter, which is a useful addition to any household toolkit. With one, you can check for continuity of all conductors and for, at least, a high resistance between all conductors. Obvious faults will be picked up, if not accurately quantified. If this doesn't sound within your capabilities maybe you'd be best swallowing your pride and calling in an electrician. We don't bite and we don't always cost the earth! (And ninety percent of our daily callouts are to lighting jobs.)

would this be the type of multimeter http://www.maplin.co.uk/products/module.asp?CartID=040825222735385&moduleno=4402 for the job.

i dont think that it is time to give in yet with a little time and effort i am sure i will get the job done i am a welder to trade and not afraid of a little electricity not that i am gung hoe.

but will treat it with the respect that it deserves just not sure of some of the terminology that you use.

i take it that i should check everthing back to the fuse box to see that i get the same readings at each junction light switch pendent (the continuety)

the part that i am not sure about is the high resistance between all conductors. conductors being the wires them self yes.

is there any guilds on how to test circuits and what type of readings i should be getting.

 

[dingbat]

From your response I'm not convinced that you are sufficiently equipped to carry out the sort of tests that that you should.

Why not read up about it before you commit yourself?
Here's a link that might help: Electrician's Guide

 

[cando]

From your response I'm not convinced that you are sufficiently equipped to carry out the sort of tests that that you should.

Why not read up about it before you commit yourself?
Here's a link that might help: Electrician's Guide

thanks for everything now that i have every thing that i need. read the guild and found exactly what i was looking for. mabe i did not ask the right question in the first place this forum rocks many thanks