Fault

[Tris Zanker]

Been called to a fault today customer saying RCD tripping when under load.

I go rcd holds in till he plugs something in that say uses more that 50w, I try and ramp test rcd - no trip, 5x no trip, 1x no trip, rcd test bottom - no trip. so I think it’s a faulty rcd, i put a new rcd in and test again 5x no trip, 1x no trip, rcd test bottom - no trip same thing again as soon as he plugs something with some load in it trips the new rcd out.

I look in to it a bit deeper IR on all circuits >20M.

I then disconnect the main earth from the PME, everything is then fine, RCD trips correctly and stays on under load, I've now decide it's done to the DNO so out comes western power they that one look and say nope it’s on your side it must be a faulty appliance.

In the mean time I’ve replaced the consumer units Main switch with an RCD due to the property having unstable earth.

Any ideas as to where i can go from here as it’s something I’ve never came across before?

 

[telectrix]

i'll put a tenner on it being a fault outside the customer's installation.

 

[hasel5]

Crumbs cant afford that sort of money thats 2 hrs worth of labour in the present climate according to agencies

 

[sedgy34]

Well the op said he was called out to a fault
so it has been working
hes changed the main switch
DNO saying nowt to do with them
no new meter
hes done ir on circuits and all >20Meg
Im thinking it's an appliance that's started to Cause this problem it's the freezer with the lead pipe in the kitchen lol

 

[telectrix]

or is it the rev. with a revolver in the dining room?

 

[johnboy6083]

This is one of those times that a pat tester or a pat adaptor will be good idea!

 

[hasel5]

or is it the rev. with a revolver in the dining room?

Thats being silly as we we all no the rev is above fault

 

[telectrix]

more likely above a choirboy

 

[Guest55]

i'll put a tenner on it being a fault outside the customer's installation.

who gets the tenner if youre wrong ?
i've got the area engineer on line 2 wanting his 50%.
;-D

 

[hasel5]

who gets the tenner if youre wrong ?
i've got the area engineer on line 2 wanting his 50%.
;-D

Has he a CIS card as that could save me a quid

 

[sedgy34]

who gets the tenner if youre wrong ?
i've got the area engineer on line 2 wanting his 50%.
;-D

Hes already eliminated he don't have a cscs card

 

[Clive P]

Might be worth checking the configuration of the main neutrals in the CU. I had one awhile ago where a friend asked me to check out a CU his son had installed ( an apprentice ), and he had the Neutrals configured incorrectly in the Board, with so many configurations possible these days its easy to get one wrong and to miss it when you look at the Board. Everything worked fine until an appliance was plugged in and then the Board tripped!

Regards.

 

[captainkev]

check any appliance on a fused spur, got a simliar problem recently in a static caravan and after a few hours got it down to a trapped flex at back of built in gas oven, plumber out to remove appliance then repair and plumber to refit oven!!

 

[telectrix]

so the cable was just trapped, not wrapped round a hot pipe or burnt with a blowlamp? bloody poor plumber if you ask me.

 

[linetech]

Might be worth checking the configuration of the main neutrals in the CU. I had one awhile ago where a friend asked me to check out a CU his son had installed ( an apprentice ), and he had the Neutrals configured incorrectly in the Board, with so many configurations possible these days its easy to get one wrong and to miss it when you look at the Board. Everything worked fine until an appliance was plugged in and then the Board tripped!

Regards.

Same thing happened to me and my partner few weeks ago.. After trying to look too deeply into it the matter we found it was right in front of our eyes.. Silly mistake, yapping about one thing an another distracted us from the obvious.. Check the neutrals.. :blush5:

 

[Knobhead]

This was a fault in an existing instalation, unlikelly to be swaped neutrals.