New Light not working correctly

[Hargen]

Hi have just changed an existing ceiling light which had a transformer 240 - 12v with one very similar, just the output was different. I switched on for the first time and the new light started off dim then brightened and then dimmed again.

I removed the light to check that I was getting 240 across the live and neutral - (tested with the earth) and that was ok, so I checked the continuity as the light has a quick plug and I then noticed that the Earth and Neutral were making a circuit even out of the terminal block. Now i do not understand enough about the Ring main to understand if this is correct but i suspected it was not, but also why would it no be different to before?

Any assistance would be great.

 

[malcolmsanford]

I'll see your dim light and raise you a loose connection or a faulty transformer, over to someone else

 

[Hargen]

thats what i first thought but did not explain why i was getting a circuit on the bare E & N wires from the ceiling

 

[malcolmsanford]

Because you neutral and earths are commoned back at your CU, and you would be picking up all sorts of readings through other appliances.

When you say circuit i'm assuming you will be using a multi meter.

 

[Hargen]

yeah on on 'bell mode'

 

[telectrix]

exactly as malcolm said. your N and E are joined at source so they will give you a continuity reading. as for the fault. time to call in a spark

 

[malcolmsanford]

So make sure you have connected it properly and the cables are all connected as they should be, everything is tight or you haven't screwed onto insulation rather than the copper and try it again.

If same then if the old one is still working put that back up and if that works then it's your transformer more than likely or a loose connection in the fitting.

 

[Hargen]

yeah maybe, council house though, I think I will try taking the light back first as it could be the transformer I have just put on another light onto the L & N standard ceiling rose and it works fine. so off to ikea we go.

Thanks for your help unless anyone else has got some other options

 

[malcolmsanford]

Fault finding Tel and mines speciality, no job too small

 

[Hargen]

Thanks Malcolm, the fitting Ikea supply is a ****e quick fit terminal block that is a bit iffy to say the least I am going to give it one last go before taking back to shop.

 

[telectrix]

just make sure you fit the transformer the right way round. the secondary does not like 230v up it.

 

[Hargen]

I just fitted the light again and put a tester onto the transformer, it gave an output of 4v but when I put my tester on the main earth going into the transformer and tried testing the output, it made the lights go brighter and stayed there, and was then outputting 16v when I earthed on the stainless rose. I think it is going back as it may be knackered or wired wrong.

 

[Hargen]

and it was buzzing when dim.

 

[telectrix]

sounds like the transformer to me, but that's an opinion based on not seeing it. ther could be an underlying wiring problem. only way as i see it is to replace the transformer, then, if it still does not work, call in an expert.

 

[Hargen]

thx guys