I am an absolute n00b when it comes to home electrical systems. Please do forgive me if this is a repeat question since I wouldn't know what to search for.

I am in France and I have 230V supply at 50Hz. A couple of hours ago, I had a short circuit that "tripped" the electricity.

The short circuit occurred in a wall point:

enter image description here

The circuit breaker (I assume that is what it is) had tripped (the switch was at '0') and I reset it by turning the switch to '1' as shown:

enter image description here

Now after this, I noticed that none of the plug points in the room that the short circuit had occurred are working! None of them are functional. However, the lights are working in this room.

I also have a water heater in the room that the short circuit occurred. I know that I can wait for a while to find this out but is the heating element of the water heater also non-functional now? AKA: will I not have hot water tomorrow?

I read somewhere that such a problem is caused by a GFI thingy and I was not sure if my water heater was hooked to this GFI thing.

The water heater label is as shown: enter image description here

I request and appreciate some patience with your answers or comments. Since I know nothing about these matters, it would be appreciated if you could explain it to me like you would to a three year old.

I have read online that major appliances like water heaters and refrigerators need to have a dedicated circuit. I don't know if this is a US rule or a Europe rule. Nevertheless, my microwave didn't have a dedicated circuit as I plugged it into a wall. Does my water heater have a it's own dedicated circuit? Why are the lights working in my house? They count as "major appliance"?




Is it relevant that power points are not working but the lights are? Does something need to be "tested" or switched OFF and then ON again on this:

enter image description here

1 Answer 1


Find the Fault

Firstly, the problem is almost certainly not your GFCI or Circuit breaker.

What has happened is that a fault has developed in your water heater or in your power outlets or someone has hammered a nail into a wall and punctured and shorted a wire. The circuit-breaker has then done the right thing and isolated the circuit to prevent your house burning down in the night whilst you are asleep.

You need to find that fault.


Your lights are on a separate circuit, that's why they are not affected.
enter image description here


Your main distribution board looks like it is fitted with fuse-carriers (not with more modern MCBs or RCBOs). You need to open up the relevant one and check the fuse inside for continuity.

It isn't clear to me how your subsidiary distribution board is connected to the main distribution board. In my part of the world, a subsidiary board is fed from one of the fuses (or MCBs or RCBOs) in the main board - which are labelled to make this clear.

In your case it isn't clear but I'd turn off power to the building and then check fuse 6 since the symbol on that looks a bit like a water heater.
enter image description here

You should only replace this after you found and fixed the fault in your heater room.

It might be that the overload in the room with the heater blew the fuse in the main distribution board as well as tripping the MCB in the subsidiary board (the one with the 0/1 switch). That fuse probably supplies power to the subsidiary board which divides it between the heater and sockets and a couple of other circuits.

If so, the 20A fuse in the main board isn't rated for a full 64A load that your subsidiary board is fused for (20 + 32 + 16 + 16). That doesn't seem right to me.


  • MCB - Mini Circuit Breaker - has an on-off switch that detects overcurrent faults
  • RCBO - Residual Current Breaker with Overload protection - has a reset pushbutton
  • GFCI - What Americans call a RCBO (roughly equivalent anyway)
  • Fuse - Contains a wire that sacrificially melts to protect you when a fault occurs.
  • Thank you for your detailed answer; I actually understood what you were saying. I find that the water heater doesn't seem to have a problem since it recharged through the night and I have hot water again in the morning. However, it might be that one of the two-pin fuse carriers has a blown fuse since in one room the two pin sockets do not work. So to replace the fuse (I have replacement fuses with me), should I turn the circuit breaker to OFF, open the fuse carrier, inspect for burnt or damaged fuse, install new fuse if necessary and then turn ckt breaker to ON again?
    – dearN
    Jun 5, 2014 at 5:23
  • @drN: Yes, turn main circuit breaker off, replace fuse, turn on. Jun 5, 2014 at 7:55
  • Before I do that, is there someway I can tell if the appliances that were connected to the point are ok as well? I know that I can connect said appliances to other working points but I am worried that if the appliance is ALSO burnt, then I may lose the other points too!
    – dearN
    Jun 5, 2014 at 8:05
  • @drN: There's no easy answer to that. You can check them visually for signs of charring, loose or damaged cables, water leakage into the interior, loose metal parts inside, etc. You can open them up and inspect the insides for similar signs of damage. You can have an electrician check them. Jun 5, 2014 at 9:07

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