How to troubleshoot / isolate electrical fault

TokyoJoe

Hello ,

We seem to have an electrical fault in the house that was causing the main fuse box to trip out once every two weeks or so . In the past it generally happened in the evening / early morning whilst we slept.

Over the last couple of weeks this has become more frequent typically occuring every day normally between 17:00 - 19:00.

It does not apper to tie in with any particular event like the central heating coming on or someone switching a light on or plugging in an electrical appliance. Although we have 10 or so seperate circuits it is allways the main breaker that trips.

To further complicate matters we had a power cut today for approx 10 hours. EDF stated that they had to cut the power to 50 homes to deal with a fault at the sub station but they claimed that this would not be related to our house as the main circuit tripping allways indicated an internal fault.

I know we can call an electrician to look at this be but before we get to this stage are there any other tests we can do to help isoltae the fault?

rjm2k1

I'm not an electrician but I would guess that since it's the main breaker that's going rather than the individual ones the following should be looked at :-

1. There is a fault within the fusebox itself.
2. The main breaker is a lower rating than the one that should be tripping.
3. There's something incorrectly wired into the main breaker rather than a seperate breaker.

2 is the easiest to check for by just looking at the fuses, the others would require some electrical knowledge.

BobProperty

I'm not an electrician but I'd consider the CH thermostats or the main earthing method as possibilities. I don't think you can do much except get an electrician to check it out.

Canucklehead

Hi

Turn off one fuse/circuit each day between those times until you find one that stops the tripping.

Corgi Guy.

Nobleck

Came across a similar fault last week , it turned out to be the fridge.

tomstickland

Canucklehead wrote:

Hi

Turn off one fuse/circuit each day between those times until you find one that stops the tripping.

Corgi Guy.

This is what I did when I had an electrical fault that caused a trip after a few days.
Turn off one circuit at a time and leave it for a few days or until it still trips out. Once you find one that never trips then you've got it.

Nobleck

Actually unplug any appliances that do not need to be plugged in, that includes the kettle, an appliance does not need to be turned on at the wall to cause an RCD to trip off. If the rcd trips out more frequently, turn off all of the mcb's and try resetting the rcd, then turn each mcb back on, if the rcd goes off when applying an mcb into the on position you may have discovered the location of the problem (e.g upstairs sockets) so then unplug everything relating to that particular circuit, and then reset the RCD.
If the RCD stays in(on) then begin plugging the appliances back in.
If the RCD trips again the chances are it was one of the appliances that you plugged in.
Favorites include:
Kettles,toasters,fridges/freezers/washing machine/tumble dryers/electric irons and heaters etc.
Out of intereset what make is your fuseboard? as i have discovered recently that HAGER RCDs trip out during power cuts.

TokyoJoe

Guy's thanks for all the tips. Slightt strange in that since EDf completed the external electrical work at the sub station the power has not tripped ( at least not in the last 5 days ) . i am tempted to go back to EDf who told me that there was no way it could be an external fault if the internal power switch was ttripping.

Shrimp_Stu

To resurrect this thread, this morning my electricity tripped out and I have discovered that it is the washing machine that is causing the electricity to trip out. The problem is that I had just switched it on and it started its washing cycle so the washing machine is full of water and now it cant finish its cycle!
Are there any steps I can take to get the washing machine to finish - shall I try turning it on at another plug socket (using an extension lead)? Turn off all the sockets and plug in washing machine on its own.
I suppose that I need a new washing machine but I need to drain the water out first!
Any suggestions welcome............
Thanks,
Stuart

shandypants5

Hi Stu...
Is the washer triping out just 1 trip? or the big one at the end that cuts off all the power to the house?

If its the main trip at the end it is probrably just damp wiring somewhere in or near the washer causing the problem.(washing machines are always tripping out these type of trips as they are Vsensitive to damp)

If you can dry the area out ,(with a fan heater maybe) then you may get it to work for a while so you can empty the machine.. But then it will still need attn from an electrician or a plumber.

On the other hand ..if it is tripping the individual trip for just the sockets.. then it is a "real" electrical fault and will need an electrician before you can get it to run..

squeaky

Shrimp_Stu wrote: »

The problem is that I had just switched it on and it started its washing cycle so the washing machine is full of water and now it cant finish its cycle!
Are there any steps I can take to get the washing machine to finish - shall I try turning it on at another plug socket (using an extension lead)?

Yep.

Turn the power off and then ease the machine out until you can reach the outlet hose.

Have ready:-

A washing up bowl
A flat casserole or oven dish
Several old towels

Unhook the outlet hose and lower it into the washing up bowl... water will drain into the bowl.

Note:- Don't start to lower until you are over the bowl.

As the bowl gets close to full, raise the hose and hook it back into its usual place while you empty the bowl.

Note:- No need to fill the bowl completely full because you'll end up spilling loads when you try to empty it.

Repeat the first step until the draining water is a trickle.

Now carry on again but use the oven dish. It should have lower sides than the bowl - that allows the highest pount of the hose to be lower and so you'll get some more water out..

Hook your hose back in place properly, mop up any spills, put the machine back.

Turn the programmer to an off / finished position.

Turn the power on.

Check washing powder and conditioner drawer sections and fill as appropriate.

Select your program...

And finally...

Sit down and have a nice cuppa tea and a biscuit.

Tip:- If your washing machine ever gets stuck half way through a wash because of a breakdown and you need to get your washing out while waiting for repair - this is the way to get the machine empty enough to allow you to open the door.