Duff electrics

[ezzzekiel]

ok here goes,
with socket circuit switched on lights go dim, switch off mcb for sockets lights are fine, similar with other circuits ex. cooker circuit is fine with sockets off but drops off when sockets switched on.

seen similar with a damaged service fuse and loose neutral at incomer but both checked fine, (mate on the job at minute and rang for a quick fix) cant think off anything else unless im missing something?

 

[accordfire]

Did you write that title on your job sheet lol?

You've got an L-N or L-E short somewhere on the sockets fella.

 

[ezzzekiel]

nothing tripping

 

[accordfire]

nothing tripping

It won't necessarily - could be poor insulation......

Disconnect one side of the ring, sockets off one at a time......and see where the fault comes back....

Duh! - Fault disappears, not comes back.....

 

[ezzzekiel]

mate just swapped the meter (meter engineer for bg) and fault (has apparently) just appeared - so going from the info im given cant see the sudden connection

 

[accordfire]

Strange.

Does fault disappear when old meter put back in?

If so, faulty meter.

Possible something touching in tails too....?

 

[ezzzekiel]

he swapped meter out for a reconditioned one still same so replaced with new one still the same? mentioned the board looked newish but supposedly been fitted a few months

his problem being he cant get a polarity check on the sockets which he needs to confirm the job is ok

 

[WDMDL]

I'd have said more to do with high resistance connection on the incoming supply.
Most likely voltage dropping under load (Measure it!) - any type of loading that significantly dims the lights on a good installation would certainly trip the relevant MCB.
Do a PSCC at origin - you will likely have a miserably low figure and something somewhere will be getting very hot under load.

Also, particularly if TN-S do the PEFC.
If the PEFC is significantly higher than PSCC you have a high resistance connection on the incoming neutral, most likely on the DNO side.
This would tie up with not being able to get a correct polarity test on the sockets, as the neutral will be lifting up several volts relative to earth with this fault.

Simon.

 

[accordfire]

Hmm

Poss reversed LN on a socket somewhere then.....

What is he getting when he does his polarity test?

 

[ezzzekiel]

I'd have said more to do with high resistance connection on the incoming supply.
Simon.

i suspected this seen it before, where a damaged service fuse hadnt blown but created a high resistance and was actually coming from a linked fuse from next door but he swapped customers fuse and says its not linked incoming direct from street

getting no reading with martindale.

 

[ezzzekiel]

I'd have said more to do with high resistance connection on the incoming supply.
Most likely voltage dropping under load (Measure it!) - any type of loading that significantly dims the lights on a good installation would certainly trip the relevant MCB.
Do a PSCC at origin - you will likely have a miserably low figure and something somewhere will be getting very hot under load.

Also, particularly if TN-S do the PEFC.
If the PEFC is significantly higher than PSCC you have a high resistance connection on the incoming neutral, most likely on the DNO side.
This would tie up with not being able to get a correct polarity test on the sockets, as the neutral will be lifting up several volts relative to earth with this fault.

Simon.

pme system and he dosent have the gear to carry out those sort of tests

 

[WDMDL]

Well there's obviously some power there, so maybe the actual voltage that's getting through under load is below the threshold that the Martindale will light at.

Bet it reads correctly if the loading is removed from the sockets before testing.

Simon.

 

[rocker]

Erm this is probably rubbish but is there any way it's a split load board that has somehow been wired in series? Had too many beers to think about it proerly, so I'm just throwing it out there.