RCD trips during the night - possibly during a thunderstorm.

Won't turn back on.

Disconnect and reconnect circuits one by one to find the one
responsible. Completely repeatable: turn on the circuit and the
RCD trips immediately.

Turn off switches on all the sockets on the responsible circuit.
RCD doesn't trip any more.

Turn the sockets back on one by one. RCD still doesn't trip.
Now what?

-- Richard

Richard Tobin wrote:

Turn off switches on all the sockets on the responsible circuit.
RCD doesn't trip any more.

Turn the sockets back on one by one. RCD still doesn't trip.
Now what?

If there's a next time, turn the sockets *off* one by one!

On Sat, 25 Jun 2016 10:26:42 +0000 (UTC), Richard Tobin wrote:

Disconnect and reconnect circuits one by one to find the one
responsible. Completely repeatable: turn on the circuit and the
RCD trips immediately.

Just to be clear, is that with all the other cicuits fed through that
RCD off?

Turn off switches on all the sockets on the responsible circuit.
RCD doesn't trip any more.

Turn the sockets back on one by one. RCD still doesn't trip.
Now what?

What appliances are connected? Lots of equipment with switched mode
power supllies? That's computers, tellies, DVD/PVR, set top boxes,
printers, routers, switches, switched mode wall warts, etc).

They may well "leak" quite a lot through their supression components
when all powered up together. Switch them on sequentially and you
don't get that excessive "leak".

--
Cheers
Dave.

In article , I wrote:
RCD trips during the night - possibly during a thunderstorm.

Won't turn back on.

Disconnect and reconnect circuits one by one to find the one
responsible. Completely repeatable: turn on the circuit and the
RCD trips immediately.

Turn off switches on all the sockets on the responsible circuit.
RCD doesn't trip any more.

Turn the sockets back on one by one. RCD still doesn't trip.
Now what?

It's just gone again, and this time one switch made a difference: a
switch controlling a security light in the garden. Which seems
plausible: presumably some damp has got in there. And maybe the order
of turning them on is what caused it not to happen before.

Thanks to those who replied.

-- Richard

Could you have some kind of carbonisation?
If its in multi sockets only a little bit more leakage probably pushes it
over the top when reconnected, but if you ramp up the drain gradually then
it holds. One could test this by doing the c gradual power up, then tripping
manually. If it reconnects OK
Then i don't know, but in my expeerience it is either minor leaks de to
carbonisation, some connected device with a leak, or a faulty rcd.

In that order.

All thunddrstorms should do is induce a momentary current into a circuit,
that can trip things but they should reset as you say.

Have you got megga?
Brian
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"Richard Tobin" wrote in message
...
RCD trips during the night - possibly during a thunderstorm.

Won't turn back on.

Disconnect and reconnect circuits one by one to find the one
responsible. Completely repeatable: turn on the circuit and the
RCD trips immediately.

Turn off switches on all the sockets on the responsible circuit.
RCD doesn't trip any more.

Turn the sockets back on one by one. RCD still doesn't trip.
Now what?

-- Richard

On Sat, 25 Jun 2016 12:37:01 +0100, Brian Gaff wrote:

All thunddrstorms should do is induce a momentary current into a
circuit, that can trip things but they should reset as you say.

Can also damage the filter compenents wired directly across the mains
inside the appliance. Not kill 'em but enough to ake 'em leak a bit
more.

But as the OP has now mentioned an outside light that's were my money
is going.

--
Cheers
Dave.

On 25/06/2016 14:03, Dave Liquorice wrote:
On Sat, 25 Jun 2016 12:37:01 +0100, Brian Gaff wrote:

All thunddrstorms should do is induce a momentary current into a
circuit, that can trip things but they should reset as you say.

Can also damage the filter compenents wired directly across the mains
inside the appliance. Not kill 'em but enough to ake 'em leak a bit
more.

But as the OP has now mentioned an outside light that's were my money
is going.

I feel the recent heavy rain might help cause the leakage!

On 25/06/2016 11:26, Richard Tobin wrote:

RCD trips during the night - possibly during a thunderstorm.

Won't turn back on.

Disconnect and reconnect circuits one by one to find the one
responsible. Completely repeatable: turn on the circuit and the
RCD trips immediately.

Turn off switches on all the sockets on the responsible circuit.
RCD doesn't trip any more.

Turn the sockets back on one by one. RCD still doesn't trip.
Now what?

Sounds like a classic case of RCD sensitisation. There is enough leakage
on all the circuits its feeding to put it very close to its tripping
point - but not quite. At that point even a small disturbance such as a
voltage transient or current surge will be enough to trip it. So for
example powering on a circuit load of stuff is enough to cause a trip.

Have a read through the following for a plan on tracking down the cause:

http://wiki.diyfaq.org.uk/index.php/RCD#Nuisance_trips



--
Cheers,

John.

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