Outside Lights on internal fused spur - MCB trips

[ianbrookes]

I have installed eight LED garden lights (5.4w) and a couple of PIR lights (400w total) via a Fused Spur (5amp).

When the lights are turned on via the FS the socket circuit MCB trips (RCD is ok). MCB can be flipped on and stays on.

Wiring looks good.

Any ideas ?

Thanks.

 

[Mr.Ian]

What value is the MCB, might be faulty and not be able to cope with the initial surge ? I take it the LEDs are supplied via transformer?

 

[malcolmsanford]

Well here is one for the book ..................the RCD stays in and the MCB trips !!

If it isn't a faulty MCB then you may have overload issues. Have you checked to see what load the socket circuit is taking with a clamp meter?

I would go for a dodgy MCB to be honest. What are you test results like?

 

[ianbrookes]

LED's are mains voltage. MCB is 32amp. RCD protection. SWA cable underground.

 

[steve-the-hat]

What else have you got on the socket circuit, and what rating is its MCB?

It the MCB is already loaded close to its limit, then the start up surge from the lights could be enough to trip it.

 

[ianbrookes]

test results are all normal. IR all >299, polarity correct, continuity fine, small voltage drop when circuit is switched.

 

[malcolmsanford]

Voltage drop on 400watt ...........................

What load is on the 32amp breaker

 

[telectrix]

go for the easiest solution first. change MCB. then, if it still trips, as suggested check loading.

 

[ianbrookes]

MCB will trip on short circuit or overload. RCD will not necessarily trip. So I am guessing that initial surge is an issue. May try a "C" type MCB - what do you think.

 

[malcolmsanford]

If there is a short circuit the RCD will trip first, unless the RCD is faulty? have you checked that ?

If you have a good RCD then it's either an overload problem, which I doubt as I have yet to see a socket circuit in a domestic situation reach anywhere near 32amps, so I'm going with a faulty/old/tired MCB

 

[arturas]

If there would be a short you would get a little bang in your mcb once mcb would be switched on,or i'm wrong?