Could low voltage trip RCD?

I am a UK resident with an overactive RCD between my electricity meter
and my consumer box.
After a recent break in the electricity supply to the entire street, my
RCD's started buzzing and at certain times of the day won't let me
connect anything that draws any significant amount of power (fridge,
cooker, kettle, etc) without tripping the supply.
Even when the RCD is in the 'off' position and all the fuses are
removed from the consumer unit, the RCD continues to buzz and refuses
to re-set. Surely this isn't right?
This problem is at its worst around breakfast time and in the early
This morning the RCD tripped the power at the same time as the next
door neighbour switched on her vacuum cleaner. This happened twice in
I doubt the neighbours are to blame, but I wonder -
Might I have a faulty RCD? or
Could this be caused by a low voltage supply? or
Is the RCD just doing it's job?
I'm working on a tight budget so I'd really rather not have to call in
a qualified electrician to replace the RCD if the RCD's not really
So far my electricity supplier's rather unhelpfully said that the
problem's up to me to fix because the RCD's downstream of my meter.
I thought I'd draw a few diagrams to see if it helps understand what
I'm dealing with:
1) The basics:
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Consumer unit, simplified wiring diagram:
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Consumer unit, wiring diagram as it actually appears:
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No it's not.
Ah -- it looks like you have a voltage operated earth leakage circuit breaker, not an RCD, i.e. two separate earth terminals, and the '?' going to an earth rod?
The problem could be caused by someone else's earth leakage leaking back into your system through your earth rod. This would also explain why it carries on buzzing when it's tripped off. The fix for this from your point of view is to have it changed to an RCD.
However, this is probably also showing up a fault in the supply network and/or a neighbour's wiring. You should probably notify your supply company -- it might be a broken PEN conductor somewhere in a TN-C-S network which is quite a serious fault.
Reply to
Andrew Gabriel
Thanks for taking the time to reply Andrew.
You're right I think, that the '?' in my diagram
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probably an earth connection. (I've had to label it '?' because the cable goes out of sight, passing behind the board on which the consumer unit is mounted).
I shall try again to contact my supplier in light of your very helpful comments. This time I'll try faxing my request for assistance in the hope that I will bypass the call managers and get through to someone who knows their stuff.
Reply to
Early evening and morning? are you close to a street light by chance? Ask your supplier to monitor the incomer ( it's free) Street lights are known to interfere with RCDs although usually by tripping them. If, as has been suggested, it is in fact a VFD then again you need to have the supply monitored to ensure there is nothing out of limits.
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