Garage consumer unit rcd trips out

[Mr Karl E Taylor]

Hi all , i am new to these forums so please bear with me. I am needing some advice on what to replace for this fault.
I have a relatively new garage consumer unit made by MK . 5 way unit.
It has five seperate mcbs and one rcd.
I have six flourecent lights. Each on a separate switch.
But two of them are on a two way set up. Where by i can switch them off at the front of the garage, and back on again from the back door of the garage individualy.
So two of the lights are controlled by two two way double light switches.
The problem is some times but is starting to happen quite frequently now when i switch one of these lights off it trips the rcd off inside the garage consumer unit. Switching all the power off inside the garage.

The flourecent lights are only a few years old. They are 6feet 70 watt single flourecent battens with starters made by crampton cbl61t model

The switches are good quality mk units.
The switches at the back door of the garage are ip60 weather protection switches. They are 3 double switches.
The switch at the front of garage is a double mk switch.

I was getting a arching sound from the front switch when i switched the lights off, so i have changed that and it has made no difference. The rcd still trips out.

I have narrowed it down to one or both of these two flourecent lights causing the issue. Because when i switch on and off again the other four flourecent lights from the back of the garage the rcd doesn't trip .
It can not be a faulty switch at the back of the garage as one side of the switch is connected to one of these four good lights and other rocker to one of these suspect faulty flourecent lights.

I have disconnected light 1 from the circuit and tried switching the othet light on and off again in the the garage and the result was it tripped the rcd. So i thought it must be the other flourecent light fitting that is faulty? So i Reconnected the first light fitting and disconnected the second. Result was it still tripped the rcd in the garage .

So i disconnected both flourecent lights from the cicuit and fitted two single light pendants with 60 watt bulbs .
Result was when switching the lights off the rcd does not trip out.

So would replacement of these two flourecent fittings with newer HF versions be the solution and i have two faulty fluorescents which i think is doubtful? Or is the fault with a over sensitive RCD as it doesn't do it all the time. Should i replace the rcd with a higher rating unit ? But the current one is rated at 63amp.....

I am thinking of connecting the suspect flourecent light fittings to a piece of 3 core cable and putting a plug on and trying them in a socket to see if they trip the socket breaker then i will know for sure they are faulty ?

My thoughts are its got to be either a oversensitive rcd, but its doing its job or one or two faulty fluorescent battens.
Surely i would expect the mcb in the garage consumer unit to trip out for my lights rather than the rcd in the garage unit.

 

[Mr Karl E Taylor]

pictures below are my garage consumer unit

 

[Mr Karl E Taylor]

another picture of rcd of garage consumer unit.
i have tested the rcd and it tests fine and resets.

 

[Octopus]

How did you test the rcd?

What test kit do you have?

 

[Mr Karl E Taylor]

MK Sentry
80 Amp 100mA RCD 2 Pole

Residential 6kA Residual Current Devices (RCDs)


should i fit a bigger rcd unit to this one from a 65 amp ??

 

[telectrix]

fluorescents are notorious for tripping RCDs as the ballasts have inherent leakage, usually though with more fittings than you 2. however, with then being 6ft., it could be the cause. also the may be cumulative leakage on other circuits, each below the RCD threshold, but adding together. I would replace the 2 suspect florries with LED equivalents, or modify to LED tubes.

 

[Ian1981]

MK Sentry
80 Amp 100mA RCD 2 Pole

Residential 6kA Residual Current Devices (RCDs)


should i fit a bigger rcd unit to this one from a 65 amp ??

No
It’s 63 amp not that it matters as you’ve obviously a fault which is tripping the 30mA threshold of the rcd.
That or it’s over sensitive.

 

[telectrix]

MK Sentry
80 Amp 100mA RCD 2 Pole

Residential 6kA Residual Current Devices (RCDs)


should i fit a bigger rcd unit to this one from a 65 amp ??

NO.

 

[Mr Karl E Taylor]

How did you test the rcd?

What test kit do you have?

sorry , no test kit , just pressed it and it resets . i think i might need to get a electrician in as its very annoying this ,

the thing is my parents garage has the same set up but has a old style plastic 10 way consumer unit in the garage with exactlty the same set up with lights etc and there is no issues with the rcd tripping out .

 

[Mr Karl E Taylor]

NO.

ok , that answers that . i wont change the rcd then

 

[Leesparkykent]

Without proper test equipment you are peeing in the wind. I've just read your 5 page thread on another forum...The fault should be found 1st before you just start replacing things. Your methods are haphazard.

 

[Mr Karl E Taylor]

fluorescents are notorious for tripping RCDs as the ballasts have inherent leakage, usually though with more fittings than you 2. however, with then being 6ft., it could be the cause. also the may be cumulative leakage on other circuits, each below the RCD threshold, but adding together. I would replace the 2 suspect florries with LED equivalents, or modify to LED tubes.

the thing is my parents garage has the same set up but has a old style plastic 10 way consumer unit in the garage with exactlty the same set up with lights etc and there is no issues with the rcd tripping out

 

[Taylortwocities]

And they don’t have an RCD, and you do.

 

[Octopus]

5 page thread ................. are you mad.

Only test kit and knowledge how to use it will fix this issue...

 

[rolyberkin]

Change the fluorescent to LED tubes and bypass the ballasts, would suggest you get an electrician in to do it as they will know what they are doing and can then do some proper tests. Your analogy of your parents setup being similar to yours is like saying I have the same consumer unit as my neighbour but can't understand why mine has a fault and theirs doesn't!