Mcb tripping, doing my bulb in !!

[Darthknacker]

Guys,

I've just finished installing 4 heatlamps in a smoking shed at a pub near where I live, they are controlled by 2 Danlers EXTLSW 16A(Exterior time lag switch) they work fine for about 4 hours then start tripping the breakers.

The lamps are 1200w each, wired in 4mm on two circuits, each cicuit has 2 lamps on, controlled by the time delay switch and each cicuit is on a 16a breaker. The load on each circuit is not even 9 amps.....the time switches can handle and switch any heating or lighting load upto 16a each....

Why would they trip, voltage drop in the cable isn't an issue as the furthest lamp is only 8 metres from the fuseboard.....and 4mm cable is more than. adequate for a sustained load of 2.4 kw.....

I've been a sparkie for twenty years and this is doing my head in....first time I've ever had anything to do with heat lamps.....and the way it's going it'll be the last !!

 

[Steve]

shorten the time lag . . . pesky smokers.

 

[Darthknacker]

They're both on different lags anyway...one is 4 minutes for a quick fag, the other set to 20 minutes as there's a tv in there too to watch the footy on.... Doesn't make any difference, both circuits still trip....

 

[Steve]

Did everything test out ok? Are they on RCD, RCBO?

 

[Darthknacker]

Yeah tested fine, the board they are powered from is in an outbuilding powered from a 3 phase board in the pub itself, the board has an Rcd main breaker which doesn't trip when the breakers do and none of the other circuits on the board are affected, I thought they were faulty mcbs at first so swapped them out.....but the new ones do the same thing...

 

[Steve]

You could try soak testing the heaters using normal switches. This would prove its the heaters at fault and not the switches when they knock off. In which case take them back and get a different type.

Im not a proper spark though. Someone more experienced will be along soon.

 

[Darthknacker]

I wouldn't think it's the switches, Danlers make good quality stuff and they weren't cheap £20 B&Q crap... They were £60 each....the lamps on the other hand were cheap ones that the customer bought, but that shouldn't matter at the end of the day a load is a load !!

Cheers anyway

 

[ColJack]

wait.. there's a telly outside under a roof where there can't be more than 2 walls by law?
where is this pub.. i need a new telly..

 

[Steve]

Just realised hes in yorkshire. whereabouts?

 

[Darthknacker]

Lol.....nice try !!

The tv is in the one wall that isn't open behind armoured glass !!

 

[Steve]

no seriously, whereabouts in yorkshire? lol what region of yorkshire?

 

[Darthknacker]

The best part !! York !!

 

[RF Lighting]

Do you have a clamp meter?

I'm wondering if there might be some sort of high resistance fault which is pushing the current useage up, or even possibly the lamps are actually a higher wattage than is stamped on them?

I'd try clamp the outgoing line from each circuit breaker and see what the real current draw is.

What brand are the circuit breakers, and what else is running off the fuse board which supplies the heaters?

By the way, I don't think York is the best part of Yorkshire

 

[FDJ]

Guys,

I've just finished installing 4 heatlamps in a smoking shed at a pub near where I live, they are controlled by 2 Danlers EXTLSW 16A(Exterior time lag switch) they work fine for about 4 hours then start tripping the breakers.

The lamps are 1200w each

It could be the switch-on surge of the heat lamps is tripping the breakers.
This will be many times the running current but will last only momentarily.
If the MCB's are type B, then fitting type C should help if this is the case.

Frank

 

[Steve]

It could be the switch-on surge of the heat lamps is tripping the breakers.
This will be many times the running current but will last only momentarily.
If the MCB's are type B, then fitting type C should help if this is the case.

Frank

Yes but this would trip the breakers every time they switch on if it were the case.