Slowly starting to crack up.......... HELP!!!!!

[Ginger]

hey there,

it's not my first time of posting .... just forgot my username!!!! Durrr.

Anyway, to the problem....

Am having serious problems with my groundfloor sockets and the wifes getting tetchy cause the central heating goes off as well!!. The MCB trips for no reason whatsoever at erratic times of the day.

The things I've tried so far are:

1. Disconnected everything from sockets last thing at night, but when I wakeup in the morning the breaker has tripped.

2. Moved the cables to a spare breaker on the board... still trips.

3. Measured the resistance from live to neutral with everything turned off and get infinity ohms.

4. suspected a socket had gone faulty so replaced all 14 of them

5. The only work that has been done on the groundfloor to the electrics was 10 months ago when the kitchen was extended - double oven and hob put on separate breakers and all sockets exchanged for stainless steel ones.

I don't have a megger so can't check insulation.


PLEASE ANY IDEAS CHAPS.

Forever in your debt if you can advise me on his one.

Ta

Lee

 

[Softus]

Was your previous username "dtutton"?

 

[Ginger]

NO!!!! I'm not a tosser.

I have a genuine problem and class myself as very competent. Just seeking the advise of the wise owls on here who on my previous questions have been extremely helpful.


ta.

 

[smokeyJoe]

Are you sure that it's a MCB thats tripping and not a RCD tripping on leakage to earth?

You might also measure phase (live) to earth resistance (with everything switched off of course) although as you've hinted, these low voltage tests are insufficient.

If you can't lay your hands on a proper insulation tester you could try series connecting your multimeter on current range with a separate testing voltage supply, either from a battery powered inverter or two small (~3VA) transformers (say one having a 6V secondary and one with a 12V secondary) connect the secondary windings together, the primary of the 6V transformer to mains gives you 2x mains ~ out of the 12V primary. Should work for a few minutes without overheating. Just divide the testing voltage by your current reading to obtain the insulation resistance.

 

[Softus]

NO!!!! I'm not a t****r.

Calm down - I was only asking

 

[Har_vey]

Have you tried disconecting the heating?

 

[Ginger]

Are you sure that it's a MCB thats tripping and not a RCD tripping on leakage to earth?

You might also measure phase (live) to earth resistance (with everything switched off of course) although as you've hinted, these low voltage tests are insufficient.

If you can't lay your hands on a proper insulation tester you could try series connecting your multimeter on current range with a separate testing voltage supply, either from a battery powered inverter or two small (~3VA) transformers (say one having a 6V secondary and one with a 12V secondary) connect the secondary windings together, the primary of the 6V transformer to mains gives you 2x mains ~ out of the 12V primary. Should work for a few minutes without overheating. Just divide the testing voltage by your current reading to obtain the insulation resistance.

The installation is definately MCB not RCD - RCD's on the shower.

I don't/can't get hold of what your suggesting, but thanks anyway.
I'll have to bring an Insulation tester home from work.... not been able to due to moving jobs last week and not started my new one yet - which is monday.

 

[Ginger]

Have you tried disconecting the heating?

Just via the fused spare outlets switch. Took it that it would be disconnected due to not reading the pcb through my meter.

 

[Ginger]

NO!!!! I'm not a t****r.

Calm down - I was only asking

Well I am asking advice and was not too impressed by your sarcastic response - hence my reply.

 

[slippyr4]

you've not told us that much about the installation:- is it a ring? any spurs? or a radial? what type + size of breaker?

do you have a clamp meter? (maplin sell cheapo ones for 15-20 quid)

 

[Ginger]

you've not told us that much about the installation:- is it a ring? any spurs? or a radial? what type + size of breaker?

do you have a clamp meter? (maplin sell cheapo ones for 15-20 quid)

Its a ring. The CU is a "Volex Protector" and the MCB a Type B 32Amp.

I have a clamp and under normal load (TV/Sat/Heating on/laptop on) will pull approx 0.9A. When it faults the clamp sows a maximum of 1.4A although it's probably not responsive enough to get the actual reading when the breaker trips.

 

[slippyr4]

Do you have an outside light with a PIR spurred off the ring?

 

[Ginger]

Do you have an outside light with a PIR spurred off the ring?

.

Not on this circuit.

 

[slippyr4]

Do you have an outside light with a PIR spurred off the ring?

.

Not on this circuit.

What does the clamp read when you've disconnected everything?

 

[Ginger]

Do you have an outside light with a PIR spurred off the ring?

.

Not on this circuit.

What does the clamp read when you've disconnected everything?

It shows zero amps but any trickle under 0.1A wont show on the meter due to the range - it's only a cheap meter. Why what you thinking?