RCD won't reset - help please!!!

[gk141054]

Hi folks, 30 minutes ago the sockets in my house lost power. Checked fuse box and RCD had tripped. Tried to reset it and it keeps flicking straight back off.

If I understand things correctly, the RCD serves the MCBs to the left of it (garage door, garage and dining room lights, downstairs ring, upstairs and hall ring and cooker & central heating). So if I flick off all those MCBs then id expect the RCD to reset and then I could put the MCBs on one at a time to tell me which part the fault was on, but when all the MCBs are off, the RCD still won't reset.

Anyone able to offer advice please?

TIA

 

[JohnD]

The MCBs may not help. They only break the L wire of the circuit. You may have an N fault.

UNPLUG every appliance that has lost power.

For fixed appliances that do not have plugs, such as the immersion heater and boiler, turn off the switch on the wall (or ceiling)

The fault is quite likely on a watery appliance, such as kettle, fishtank, boiler, immersion heater, pond pump, shower

And not forgetting outside appliances and lights, which are watery when rain gets in them.

Some photos of your consumer unit, close enough that we can see the main switch, and the RCD(s), and the MCBs and their labels, will help.

 

[gk141054]

 

[ericmark]

As said turning off the MCB's does not switch off neutral, only the main isolator does that, so you could try main isolator to see if there is a fault on the RCD its self.

So turn all switches off then just the RCD which is tripping back one and it should stay in as not power, then main isolator and if there is a big fault the RCD will trip, with small faults it may stay connected until you start putting on a load, if it says in switch on good RCD then all the MCB's on the good RCD if it trips as you switch on the good RCD MCB's it points to a neutral fault, if it still holds then switch on each MCB on the RCD which has tripped.

I have had over the years some weird faults, but step one is turn off, unplug, as much as you can.

 

[Taylortwocities]

My first thought would be to investigate that circuit that used to be immediately to the left of the RCD.
I can’t read the label and (obviously) the live is disconnected because there’s no MCB there. But just suppose that the wiring is still in place and the neutral is still connected to the busbar. Any bit of damp etc on the other end of the (still connected, but redundant) cable would trip the RCD.

It’s worth a check. I’ve been caught on this before…
If you not sure what to look for, turn off the MAIN SWITCH and take a pic if the wiring inside. It may reveal something obvious, or it’ll raise a laugh or two.