Any electricians?

  Marko797 11:31 26 Feb 11

Can anyone explain how, after 5 years, in a new house, connections can become loose and start arcing and sparking in my consumer unit?

My house power sockets kept tripping last weekend, and on re-setting the rcd resulted in sparks and smoke from the consumer unit, which is well out of reach, and in my garage. There was also some melting of the plastic case at the top. It did trip the rcd, so there was no fire, luckily, so to some extent you could say it did what it should have done.

It wasn't down to any appliance plugged in, but down to a loose connection which had developed within the unit itself, at the neutral busbar, not at the rcd.

It's all sorted now temporarily by a qualified electrician, who kindly came out at 1030 in the evening, & I need to replace the consumer unit.

I was left wondering how it happened in the first place, as it's not as if anyone ever goes near it, there are no moving parts, plus, like I said, it's high up and well out of reach.

  howard64 11:36 26 Feb 11

ac supply does cause screws to either tighten or loosen. Normally when done up really tight they stay. The regulations suggest a full electrical inspection after a max of 5 years but most people do not have it done until something goes wrong. I was an electrician with London Electricity and then taught electrical engineering for 25 years at a college.

  Marko797 11:43 26 Feb 11

that's interesting - ac supply can cause tightening or loosening - but difficult to comprehend as a non-electrician.

So I assume then that it would not have been down to shoddy work by the original installer, but the science of ac supply is the cause?

The electrician who came out and fixed the problem said that the inspection period is now 10 years as per a new IEE regulation.

  Forum Editor 11:48 26 Feb 11

after it has been installed for a few years, and you will stand a good chance of being able to tighten the conductor retaining screws (you should not try unless you are qualified to do so).

As howard64 says, screws that are properly tightened in the first place should not work loose, but not everyone tightens properly. Sometimes the conductors are moved slightly under the screw as an electrician rearranges cables within an enclosure, and this can lead to subsequent problems.

  hssutton 11:50 26 Feb 11

"So I assume then that it would not have been down to shoddy work by the original installer, but the science of ac supply is the cause?"

I think you assume wrongly, as Howard says If the screws are tightened correctly, then they stay tight.

I've seen/changed many sockets due to the screws not being tightened correctly resulting in overheating.

  Marko797 11:54 26 Feb 11

so would it be reasonable for me to return to the original installer and request them to consider replacing the unit as it is likely down to improper fixing & tightening on installation?

I imagine they would argue it lasted 5 years so they have no responsibility to replace.

  howard64 12:00 26 Feb 11

it will depend on their customer service and whether they feel there is any further business to be had. I have never had to go back to an installation that I did except for failure of installed equipment.

  howard64 12:01 26 Feb 11

if your house is less than 10 years old I wonder if the National House Building guarantee might cover it?

  Marko797 12:10 26 Feb 11

yes the house is less than 10 yrs old - it's 5 yrs - so I might look into the NHBC guarantee.

I've been quoted £420 to fit and replace, but if this is covered by the NHBC, then that would be a good saving.

I think, initially, I'll go back to the original installers and see what they have to say. Their name sticker is, after all, on the consumer unit along with phone & address details.

Thanks again.

  Marko797 12:12 26 Feb 11

I'll mark this as resolved for now. Thanks to all for input.

  Marko797 20:19 03 Mar 11

thought I'd return to this and let you know that the original installers (after I emailed them) have agreed to replace and refit a new consumer unit at no cost to myself.

I wasn't covered by NHBC (apparently) after a 3 year period.

I can't help but think, however, that this might be due to the fact that my neighbour was the site developer! Regardless, it has worked out well at this end and saved me a bill.

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