Ground floor lighting trips out mcb

[Biggy]

Hi everyone,

My first post but straight in with a couple of issues.

I'll start with a 6amp MCB that keeps tripping out relating to ground floor lights.
For your info:

There is 10 x 3w led recessed lights in Kitchen, 8 x 3w led recessed lights ,plus a main central Led light (approx 100watt equivalent ) in the room next to the kitchen and then the same amount of lights and Main central light in the Back room. I would say the combined wattage including two outside lights (40watt each) will be around 480w so let's call it 500watt on the ground floor.

From my understanding a 60w bulb draws around 0.5amp so in effect 30 of the 60w bulbs (around 1800watt combined ) would require a 15amp breaker which would be comfortable, so based on this theory is the 6amp MCB actually overload on 500watts on Ground floor and this tripping the breaker .

The breaker does not trip immediately as can take 5-10mins sometimes longer, and in some instances it has tripped even when ground floor lights have been OFF.

The joist spaces have all been insulated with rockwool if this makes any difference as I want to eliminate any possibility before I start questioning my electrician who advises that maybe I should fit a 15amp breaker in as he feels 6amp is less power for 30 odd lights .

Can anyone shed LIGHT on this

I'll come to the second issue after I can get a solution to this.

Sorry for the lengthy explanation but I know there's nothing more frustrating than not arming knowledgeable people will full info and expecting solutions. Hope I've not missed anything out.

Hope to get a few responses and guidance as I have basic understanding of electrics.

Thanks

 

[Toneyz]

Outside lights don't have sensors. Am in toolstation now and with pick up outside bulbs and check them and report back later tonight.

thats rulled that out then!

 

[Risteard]

Sparky that wired all house now not answering his phone.

Maybe because it's the Christmas holidays?

 

[Midwest]

I will get building control to chase him up and let them know the wiring needs independent testing through them as I feel it is unsafe for me and my 5 young children.

I don't think they will show much interest to be honest.

 

[littlespark]

Without knowing your competency and experience working with electrics, I would advise NOT to take the cover off the CU to swap cables onto a spare breaker.
Safe isolation or not, this is a job for a qualified spark.

That said, you don’t need a spare mcb... just swap the downstairs circuit with maybe upstairs lights circuit and see if the fault moves over too. Then you’ll know if it’s the wiring or a weak breaker. (Swap the neutrals over too, if they’re on different rcds)

Are you certain the breaker trips even with all switches off? This would rule out any lamp or driver.
Is there anything in the circuit that has a permanent supply from this circuit that isn’t a light? Someone has already suggested an outside PIR. What about doorbell transformer, smoke alarms, burglar alarm, electronic switches such as dimmers?

 

[Biggy]

There is smoke alarms hard wired to each floor and a heat alarm in kitchen. On the same floor there is one smoke alarm and one heat alarm in different places.

They seem to operate fine by looks of it.
Did have a problem with them where they kept chirping but guy said it was a loose connector and pushed it in real tight and chirping stopped.

Nothing else powered by circuit I don't think other than lights .
Outside light bulb fitted now and linked to the circuit but nothing tripped just yet and I've left everything switched off now and come back home so will see if it flips down again in the morning, which it more likely will.

 

[Midwest]

I've lost track here now with other similar threads, but why OP don't you ask your installer to come back & rectify? Or have I got the wrong thread again.

 

[Biggy]

As you will see there is another 6amp breaker for upstairs lights (first one from left) so is it any easier to swop them around as it is or not just to test the breaker ?

View attachment IMG_20181228_172814.jpg

 

[littlespark]

Looking at the photo, it wont be easy to swap the 2 circuits as you'll need to untangle the neutrals to swap them over as they will be on different neutral bars.
As I said before, its not advisable to go poking about in there if you're not experienced.

 

[DC-backfrom the past]

I think the only thing you could do yourself is check the wiring at the switches to see if any cables are damaged or loose . ( you may have already done this )
ensure the power is off when you do this .
you have a short somewhere and it may be a cable thats damaged by a screw cutting the insulation, possibly at a light switch.
it could also be damage by a nail or screw through a cable if you have had other work done.
If you are not competent with electricity I wouldn't advise opening the consumer unit.
despite you switching the power off , via the mains switch at the unit you can still be in danger of touching live cables/contacts and slight chance or arcing . also if you cross neutrals you will give yourself more heartache.

 

[Biggy]

OK thanks for your input all, I have asked the sparky to come back and sort it out. He said he will pop round tomorrow so will see what he has to say about it.

I've not checked switches for loose connections but I'll get him to rectify all issues hopefully.
I'll update tomorrow sometime .

Thanks again.

 

[dmxtothemax]

Sounds like a lot of electronic power regulators involved here,
Any circuit with lots of electronics involved can have problems,
SMPS are highly reactive and cheap one's even more so !
So we don't know what harmonics are involved,
But they can increase the current flowing.
I would measure the current in the circuit.
If the cables will allow it change your breaker from 6 amps to 10 amps.
See if that helps.

 

[DC-backfrom the past]

just another point do any of the light circuits downstairs have a dimmer switch ? its possible this has been damaged during testing if the spark forgot about it.

 

[Biggy]

No dimmer switches, just simple basic switches.

As for changing from 6amp to higher ampage I have been advised on this thread not to as 6amp should be sufficient to power up 1380watts and my combined wattage is not even 500watts so why increase the ampage ?

 

[Midwest]

Did you reply to my query #18?

 

[alasdairp]

Unless it is certified that all the lighting circuit wiring is in 1.5mm^2 then the maximum 10A MCB is allowed. The 6A MCB should be more than adequate. If there are heavy switch-on current surges then a C6 (instead of a B6) MCB is allowed - that allows a higher short-term surge current before tripping. In your two photos, the cooker MCB seems badly out of alignment in the detailed close-up photo. That suggest that it was not fitted correctly or its mounting is damaged and it should be inspected by a qualified electrician.