Immersion Heater tripping electricity?

Jo.G

I will! Thanks to both of you for your advice.

Jo.G

macman wrote: »

You said it tripped the 'socket' MCB. You probably have more than one ring main in the property, unless it's a small flat (most newer houses have two or even three: upstairs, downstairs and kitchen). That should enable you to narrow it down.
It may not be an actual appliance, it could be a circuit cable or socket fault. Why not switch the sockets back on one by one and see if it trips on a particular one?
But I don't understand how, if the immersion heater is on its own dedicated circuit, it can be taking a ring main out as well?
Can you list the circuits as marked on your CU, or post a pic?

Hi macman, I did take a photo on my phone but am at work so cant post it but I'll try & describe it.
From left to right:
2 switches which are labelled 'Main Switch All Circuits'
A Yellow 'Test' Button
'RCD Protected Circuits' Switch
Cooker
Sockets
Security alarm
Water

Then theres a gap followed by 2 unlabelled switches (spares?)
Lights
Porch Socket
Shower
Yellow 'Test' Button
'RCD Protected Circuits' Switch

The immersion heater was switched off last night both at the control and the RCD unit and all was fine overnight. Everything that is usually plugged in has been fine, cooker, microwave, fridge/freezer etc.

Glum

Jo.G wrote: »

We were woken up at 2am by the house alarm going off and all the power to the sockets to the house had also gone.
We had an RCD Consumer unit (I think that's what its called) fitted a few years ago and the 'socket' switch was off. I tried to switch it back on and re-set it but it wouldn't work.
In the end I switched all the wall sockets off and went back to bed.
I managed to to reset the socket switch when I got up this morning and everything appears to be working normally. We do not have a gas supply so all our heating is via Economy 7 and storage heaters. The storage heaters are warm this morning and don't appear to have been affected. The only other thing that is timed to come on during the night is the immersion heater. Could the immersion heater be the problem? Any ideas on what would have caused the immersion heater to do this?

TIA

If the insulation inside the immersion heater element has broken down then you are probably getting a partial short-circuit to earth. Trips can be confusing. Whenever I get a fault it tends to trip the main switch on the distribution panel rather than an individual breaker. I would start by turning off the Water switch and make sure nothing else trips out overnight, then, with the power off, carefully inspect the wiring in the immersion heater head, and if possible, test the element.

Changing an immersion heater is not a big job if you know how to turn off the water feed and drain down, and you have the big spanner to unscrew the element from the tank without causing damage to the cylinder. Search Youtube for "immersion heater replacement".