Temporary lights out after rainstorm

[aroominyork]

There was a heavy rainstorm yesterday. Afterwards, the lights in two rooms were out (GU10s in the ceiling) though the other power in the rooms was fine. No tripped fuses. This morning they are working again. Any ideas of the cause please, and whether something needs attending to?

 

[FatAlan]

Any obvious signs of leaks into any electrical fittings? Any outside lights, fittings or sensors connected into the lighting circuit? Only real way is to get a spark to do some testing for you though.

 

[stewartrossinv]

Regardless of fuses not blowing/mcb's not tripping, this has to be investigated by an electrician. As the failure followed on from heavy rain there may well be water penetration that you can't see which has the potential to cause serious damage to your electrical system, and at worst the possibility of a fire if your circuits are not suitably protected against earth current leakage amongst other things.

I'd advise you get this attended to by an electrician as a matter of priority, before what appears to be a minor fault becomes a major one.

 

[aroominyork]

Thanks Alan & Stewart. I've booked an electrician to visit on Friday.

Will he be able to test water leakage from an electrical test or will he need to dig into ceilings/roofs to see whether there are any leaks?

 

[stewartrossinv]

It's impossible to say for sure without knowing how your lighting circuit runs from your consumer unit to the lights concerned, and indeed what potential defects (if any) in the building or its drainage environment might account for water penetration into cable runs, fittings or back boxes. Unless the light fittings/back boxes and so on show signs of water ingress, the electrician may not find direct evidence of water penetration. However, he or she may well be able to find indirect evidence by testing the insulation resistance of the cables concerned. End to end resistance testing might also show up high resistances from poor joints somewhere in the system which in turn could be affected by damp in one way or another.

 

[aroominyork]

Well, the electrician came round, did a little head scratching, went to the loft and found evidence of rats. So the rat catcher came around today and once that is resolved I'll ask sparky to come back.

 

[stewartrossinv]

Hope you can get the rats caught and eliminated. They can cause severe damage to your wiring, and I'm sure your electrician will be able to replace whatever they've chewed after they've been caught. Thanks for the update!