Advice required

Hi all, hope someone can help out with this. I am currently doing a house up and last week I fitted some cheap ceiling roses for the bedrooms, to be exact it's these:

http://www.wickes.co.uk/ceiling-rose-and-lampholder/invt/710165/

After finishing one of the bedrooms I fitted the ceiling pendant, tested the light and went out for a smoke and a cuppa. When I went back in the lights had tripped. Couldn't work out why it was tripping, I had re-checked all wiring but it was still tripping. Sometimes after 5 mins, sometimes instantly, and other times up to 20 mins. After finally unscrewing the bulbholder cover I discovered both wires charred and the insulation cable melted, the inside of the cap was black and arcing has decimated the live wire screw.

I'm not a qualified spark but have worked with simple electrics for years, and I can confirm the rose was wired correctly. Does anyone have any idea what could have caused this? Little information, the meter has a main breaker with individual MCB's for the various circuits. Meter looks like a very early breaker version and has a label saying there's two different versions of BS7671 although I haven't seen two different sets of wiring? Sorry for the long post, any advice appreciated.

First thought would be that you didn't terminate the wires tightly enough or

pushed the insulation in under the screw(s) so that only a small part of the wire was touching the contact.

Start again and see how it goes.

Hi, thanks for the reply.

I have been doing simple electrics for years and i'm always careful when wiring, that being said pendants are pre-wired into the bulbholders. At risk of making myself sound like a numpty your answer is referring to the bulbholder part of the fitting and not the ceiling rose itself? Should I be checking the wiring to the bulbholders? Apologies but i've done hundreds of these over the years and i've never come across this.

Apologies to you if it was Wickes' fault.

It could have been wired incorrectly (with the faults mentioned in my previous reply) or just a duff one. Were the prongs that touch the lamp (bulb) burnt?

Check the rest. Fit another one. Something must be loose to cause overheating.

Thanks for the replies Impudence, I will test with another one tomorrow and let you know how I get on. I don't recall seeing any damage outside of the bulbholder cap, i'll bring the offending fitting back tomorrow and post some pics.

Thanks again.