Nuisance tripping of kitchen lights

[Chrisknowlesuk]

I think I know the answer to those one but thought I’d throw it out there in case I’ve missed something...

4 x LED low voltage downlights in kitchen.
Fed from MEM 6A trip

MCB nuisance tripping.

I’ve changed lamps, switch and breaker to no avail. Can’t reach any transformers or JBs in ceiling and it’s a lovely plastered ceiling with no access. Flat is not brand new but not very old either.

I’m presuming it’s most probably an IR fault or bad connection in ceiling?? If so it could be a nightmare fix.

Any other ideas or suggestions would be gratefully received.

Thanks

 

[Octopus]

Random changing of parts isn't a good idea.

Have you tested said circuit? And if so what were the readings?

 

[NellyManjaro]

Have you done any kind of testing?? And is there any access from above??

 

[Chrisknowlesuk]

Not as yet. Going back to do IR test.

 

[Chrisknowlesuk]

Since I can’t reach the transformers in order to disconnect would a L/N connect IR to Earth test or IR test at 240v show up any fault if there was one??

 

[Octopus]

Why did you go to site without your tester? I hope you are not charging for wasted visits?

 

[Chrisknowlesuk]

I went to site to replace a bathroom door lock, kitchen kickboatds and a couple of other handyman jobs.

The lighting was an add on whilst I was there.

Isolating the other possible causes like swapping MCB and switch etc was to narrow down the offending item.

Sorry my post probably wasn’t clear. It was a 3 gang switch so I swapped circuit to a problem free gang and I then swapped the circuit to an adjacent problem free MCB (same rating of course). Moved everything back to normal as problem persisted.

 

[Octopus]

So do you have any test kit?

 

[Chrisknowlesuk]

Yes

 

[Midwest]

As the other guys have been indicating, to identify a fault, you have to start at the beginning by testing the circuit itself first. Although, I might be tempted with a quick fix myself

What actually is the 'MCB nuisance tripping' manifesting itself as, every time lights turned on, to just once in a while?

 

[Chrisknowlesuk]

Only occasionally. At first the client couldn’t get the problem to show but then after persistent turning off and on (which probsbly doesn’t help) they tripped.

They cables only come out about 6” from ceiling so can’t reach any transformers or junction boxes to check connections?

 

[Midwest]

They cables only come out about 6” from ceiling so can’t reach any transformers or junction boxes to check connections?

Well that needs rectifying, so that would be your starter for ten. Unusual though, the luminaires not fed from one single central transformer?

 

[Chrisknowlesuk]

Can’t really tell what the arrangement is with transformers and the repair maybe a bit of a mission.

It’s a flat so access from upstairs could be super difficult.

Thanks for the replies

 

[Octopus]

I would be warning the client about big holes in the ceiling needing to be cut ....

 

[Wilko]

Hi - you have said "nuisance MCB tripping" can you confirm it's an MCB and not an RCD that trips. Have you seen it trip yourself ?

 

[marconi]

If after doing the necessary testing you find no fault, I suspect the problem to be a high in-rush current when the switch is first made. LED lamps and their drivers do have high but short duration in rush currents and in your case you turn on 4 at the same time.

You could fit one of these:

http://www.cooper-ls.com/sites/coop...eets/cooper-ls-datasheet-inrush-limiter_0.pdf

an inrush current limiter with a rating of 16A.

see also:

ESB AC Inrush Current Limiter 3,6kW ... 48kW CAMTEC Power Supplies - http://www.camtec-powersupplies.com/inrushcurrentprotection_esb.html

 

[marconi]

PS: Or change LV Luminaires for Mains ones if that is a cheaper solution. In our new kitchen we have 16 Saxby 7W Mains GU10s supplied by a 6A type B mcb all switched on together.

 

[Octopus]

PS: Or change LV Luminaires for Mains ones if that is a cheaper solution. In our new kitchen we have 16 Saxby 7W Mains GU10s supplied by a 6A type B mcb all switched on together.

Given the OP has stated he can't access the transformers, this change over could be tricky!

 

[marconi]

"Chrisknowlesuk, post Can’t really tell what the arrangement is with transformers ...

 

[marconi]

Murdoch - yes. I have just read in his first post like you did that he stated he could not gain access - good point.