Electrical help!

[Luke]

If it's an inrush issue, you'll get different results plugging the plug in with all bulbs inserted, vs. screwing one bulb in at a time.

Either way, not right for a simple lighting circuit.

 

[adamfitz]

First 2 times I had all bulbs in then switched on. That was when using the dimmer. Flash out the dimmer and took the breaker out. The 2 times this morning was 1 bulb at a time. For something so simple its giving me a massive headache

 

[rtbcomp]

5 bulbs means about 6 amps inrush each, plus whatever is being drawn on the ring.

^^Luke just beat me to it, try screwing the bulbs in one at a time with the power on. Carefully.

 

[mtt.tr]

Cant see it being inrush. Given that gu10 lights are run on a 6a MCB. I would have a guess at it being damaged insulation or poor connection somewhere.

Easiest test in my mind would be an insulation test and continuance go from there

 

[bourbon]

start again with new component's?

 

[dobbslc]

I had 8 50w GU10 lamps on a 6 amp mcb along with all the other downstairs lights that totaled 5.8 amps on full load. No way should inrush be the problem . If its popping a 32a mcb there's a fault! In fact if its popping a 6a mcb there's a fault!

 

[adamfitz]

Cant see it being inrush. Given that gu10 lights are run on a 6a MCB. I would have a guess at it being damaged insulation or poor connection somewhere.

Easiest test in my mind would be an insulation test and continuance go from there

Continuity is good when no bulbs are in. I've tested from live at first holder to live at the end. Same with neutral. All ok. Havent got anything to insulation test with, I'll have to look at work when I'm home.
Will get on to the company I got the bulbs from as well

 

[Wightsparks]

Could be a faulty MCB.
Assuming you have tested with different bulbs in different sockets each time ?

 

[adamfitz]

I've tested the mirror circuit in 2 different sockets. Same outcome. What I was thinking was maybe get some normal halogen bulbs and try that? Or swap to a C type mcb?

 

[brightspark]

I've tested the mirror circuit in 2 different sockets. Same outcome. What I was thinking was maybe get some normal halogen bulbs and try that? Or swap to a C type mcb?

do not change to a c type 99 percent faulty bulbs only other possibility is lamp holders shorting out when the bulbs are in

 

[adamfitz]

do not change to a c type 99 percent faulty bulbs only other possibility is lamp holders shorting out when the bulbs are in

Ok I'll wait to hear back from the bulb supplier. The lamp holders were only Ebay cheepies so it's only a 5er down the pan if its them. Rather not cough up another 25 quid for new lamps

 

[angellonewolf]

if im reading this right you have 10 bulbs and 10 holders and when you test 5 of one lot bulbs and holders and then another 5 of bulbs and holders
and always do the same blows the mcb

 

[adamfitz]

Yeah. So all 10 bulbs in. Switch on. Trips the mcb.
Remove all wiring. Just wire 5 bulb holders.
Put in 1 bulb at a time. No particular order. Trips mcb when the 5th bulb goes in and turned on

 

[hotponyshoes]

Are you sure you have not got a wire crossed somewhere?
Take all the bulbs out, unplug it and test from the live terminal in the plug to the neutral in the plug plus every bulb holder, then swap and do the same from the neutral in the plug to all the lives in the bulb holder.

You can check for inrush by turning it on and screwing in one bulb at a time. You when you get to the bulb that trips it take it out turn on again and try a different bulb and holder. You could also disconnect another appliance (or all the other appliances) on the ring just to see if the mcb is weak or you have a fault somewhere else and the 5 bulbs just push it over the edge.

I think the dimmable led bulbs do draw a lot of current very quickly on start up as I have tried using strings of them at events that are on a 13a plug with a 5a fuse but will trip the 32a outlet from the generator when turned on. They normally work fine on a less sensitive supply so you could try connecting them to a UPS or something if you have anything available?

 

[Wightsparks]

I've tested the mirror circuit in 2 different sockets. Same outcome. What I was thinking was maybe get some normal halogen bulbs and try that? Or swap to a C type mcb?

Sorry I meant different bulbs in different bulb sockets.

Is anything else on the same MCB ? - if not might be a faulty MCB, if yes are the other loads bringing it close to 32A?

 

[adamfitz]

The mcb is the one for my main ring main. The only other thing switched on at the same time was the fridge.
I've tried the bulbs in different holders, whichever goes in 5th blows the lot

 

[Wightsparks]

Then I would try and plug it in on a different MCB circuit as a quick check.

 

[J1nx]

What resistance do you read across the lamps? Check this and then check resistance falls as expected as you insert lamps across the circuit.

I’d guess faulty holder going to earth or shorting when lamp inserted, how many times have you repeated it?

 

[CoValent]

What resistance do you read across the lamps? Check this and then check resistance falls as expected as you insert lamps across the circuit.

Don't think that'll work out with LED lamps, though. There's a driver board betwixt the contacts, not a resistive filament.

 

[J1nx]

I can’t imagine it will have much of a driver, just a couple of passive components?