installed downlights- fuse keeps blowing

themaddog · 13 Jun 2007

Hi
I have just installed 4 downlights in my kitchen. I wired them up and put the fuse back in. I turned the power on and the fuse blew. I rechecked the wires and put some new fuse wire in, turned the power back on and again it blew.

I put 6 in the front room last month with no issues.

Any ideas as to whats going on? I dont fancy being in darkness tonight

The lights are 50w halogen 240v GU10. The consumer unit is the type with fuses that pull out and can be rewired, white,blue,red etc

Thanks, TMD

EdwardCurrent · 13 Jun 2007

Hello,
The circuit didn't trip with the lights 'switched' off ?? Did the other lights on the circuit work ok ??
Have you a continuity / voltage tester that you are confident in using ?

themaddog · 13 Jun 2007

Hello mate
When i first put the fuse back in only 2 of the 4 lights came on. I went to the light switch and flicked the switch and it blew.

I checked all the wires,replaced the fuse and it blew straight away with the light switch on

I dont have a voltage tester

I noticed the earth wire had a red piece of tape round it. Is this relevant to the problem?

TMD

EdwardCurrent · 13 Jun 2007

Hi,

The plot thickens !!!!

It sounds as if you have 'switch line' and feeds crossed. Do you have 3 cables at your connection point ?

I hope that the red sleeving is not something to do with this problem, as it must never be used as anything other than an earth. Are the lights on a 2 way set up ?

Cheers
Ed.

JohnD · 13 Jun 2007

EdwardCurrent said:
I hope that the red sleeving is not something to do with this problem, as it must never be used as anything other than an earth.

Not sure what's happened here.

Photo would be good.

It would help if you can pop up to the high street and invest £8 in a multimeter.

themaddog · 13 Jun 2007

At the connection point are 2 red wires, 2 black and 2 earth.
I have taken the red as live and black as neutral

The red tape round the earth is where they wired them both together.

The kitchen light switch has 2 switches. 1 for the kitchen lights and the other for the front room. this is the only switch that operates the kitchen lights. The front room are 2 way with another switch by the front door

themaddog · 13 Jun 2007

In fact there are 3 wires....3 red,3 black,3 earth

JohnD · 13 Jun 2007

grrrr, I bet that is where the electrician used whatever tape he had handy

I was complaining about that only yesterday. more often they use G&Y on things that are not earths. Buy yourself some white vinyl tape when you are out, and use it for holding things together or marking on. Red tape in a lighting circuit ought to be used to identify switched live*

50p says you have connected the black from the switch to the incoming black neutral It's a common mistake. Did you mark and draw the cable layout of the old fitting before taking it apart?

*Switched live from the switch is usually in black wire and should be sleeved red.

themaddog · 13 Jun 2007

The light that was originaly there was just a terminal block fitting with all the blacks in one hole, all the red in one hole and the earths in one hole.

Just for your info, There are 3 cables. 2 of them are running together under the floor ( cable tacked to the joist ), the third cable seems to go in a different direction.

JohnD · 13 Jun 2007

50p says one of them goes to the switch. Go out now and buy your multimeter, when you come back we can tell you how to trace and fix.

themaddog · 13 Jun 2007

I have a multimeter now...http://www.argos.co.uk/webapp/wcs/stores/servlet/Search?storeId=10001&catalogId=10651&langId=-1&searchTerms=multimeter&go.x=0&go.y=0

What next??

TMD

JohnD · 13 Jun 2007

disconnect all the wires

mark the three cables "1" "2" and "3"

If you can put each wire into its own terminal in a connector block, that will reduce the chance of you accidentally touching one. If you can do that, set the tester to "high volts AC" in a range that includes 250v

If you test each black to each red (you will need to draw up a chart with 6 rows and 6 columns - headed Cable 1 - Red,Black; Cable 2- Red, Black; Cable 3 - Red, Black) you might find you have 240v or so between every black and every red. More likely you won't. You might find that one of the blacks shows no volts against any red. If so, you may find that it has voltage against all the other blacks. If not, operate the light switch and test again.

If you prefer not to work live, or if you haven't got a suitable connector block, set the tester to "continuity" test or low resistance. Turn off all power and check that it is off. Test for continuity between each black and every other black; and each red against every other red.Again, you may find one that has no, or lower, continuity.You may find this one has continuity with the wires of the other colour.

Please report back with your findings.

themaddog · 13 Jun 2007

right i have labeled the cables..... now am i right in saying i need to hold a probe on to black 1 and test that against red 1, then red 2 and 3. then black 2 against all the reds etc?

I take it black probe to black wire etc?

And what details do you need? The reading or if it just buzzes?

Cheers

themaddog · 13 Jun 2007

Black 1 to red 1- Meter buzzes
Black 1 to red 2-Nothing
Black 1 to red 3-Nothing

Black 2 to all the reds- Nothing

Black 3 to all the reds- Nothing

Hows that sound?

JohnD · 13 Jun 2007

yes.

Usually just tick it if it buzzes (this will be for continuity test, which is colour against same colour) but look at the reading, it should be the same number every time.If the number isdifferent, write it (and the usualone) down. When testing continuity, power must be off or your meter will die.

For voltage test (which is colour against different colour) it will probably not buzz, but will show a number, probably about 240. Tick the box where you get this; if different, write in in the box.

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

installed downlights- fuse keeps blowing

EdwardCurrent

EdwardCurrent

Similar threads