Garage consumer unit rcd trips out

[Allan Hogg]

It is not clear how the switching is carried out. Six fluorescents, four each with one way switches and two each with two two way switches.
However that is not how I read the controls and it seems that there is a 'master' switch at the front door for what are the access lights. Check this switch and if it is double poled i.e. switching live and neutral it may just be the slightly different opening or closing times of each pole which is the problem (you get a parallel path during this period which may be sufficient to trip the RCD)

 

[Mr Karl E Taylor]

Well all the electrician has been.
Results are:

Each flourecent light on start up is giving 2amp leakage?
He has checked the sockets. Checked the switches and checked all connections etc.

FOUND ONE OF MY SMALL FLOURECENT LIGHTS THAT I HAVE ON THE WALL THAT IS OPERATED BY A SEPERATE ON OFF SWITCH TO HAVE THE LIVE AND THE NEUTRAL WIRES CONNECTED IN THE WRONG PLACE.

I asked him if that might be the fault and said its doubtfull but wouldnt help.

Has measured resistance on the neutral wires from inside the fuse box.
During the test he found some thing that was pulling 20 amps or could have been milli amps?? However then disconnected every thing and still was getting this reading .

Only things that where still connected where the outside pir coach lamps.

Said this might be drawing the reading .

Also said alarm power cables are less than 1 metre away from other cables in the loft space so that might be giving the fall reading and explain the 20 amp or milli amps draw.

Tested the whole set up with some kind of meter bonding clamp .

Too technical for me to explain as only going on what he said.

There is no broken wires found on the system.

His conclusion is that the fault is in one of the flourecent lights but can conclusively prove which one .

He has said according to his readings that each light is pulling on start up more than 2amps .
I said to him well i only switch the one on.
He said it doesnt matter as all the lights are on a live circuits .
He suspects its down to leakage from the light capacitor on switch but can no prove which one .
Also said that fitting a light pendant would not prove the flourecent are fine only that the lighting circuit is fine .
As the light pendants dont have a seperate earth inside them but flourcents lights do. It could be and its a only a guess that one of the six lights is failing very slowly .

However what i didnt get was a resistance test done on the light circuit for the two light fittings when you switch them off , only when you switch them off . And this reading is 2amps .

I might have as a result a ovet sensitive rcd that is doing its job and picking up this power surch from the light capacitors when i switch the lights off as he said this electricity needs to go sone where and so is going back to the fuse box .
Which suggests its a fault in one of the capicitors

 

[Mr Karl E Taylor]

Well the rcd has tripped again in the garage again when i switch one of the flourecents off. So that rules out the small wiring issue that i mentioned in my last post.

How can you test this system on lights switching off for leakage?

It has been tested for leakage when lights are switched on .

Electrician just thinks its a fault on a flourecent fitting that is causing a leakage when light switched off , but not shown me or proved any test readings to back this claim .

Only that on start up he was getting 2amps leakage per one light fitting

Any further advise appreciated.

For me now i guess its change all these lights as can not confirm which light fitting it is .

 

[Octopus]

2 amps leakage .... that’s not feasible

 

[Mr Karl E Taylor]

Hi , why is 2amps leakage not feasable ? Thats what i was told.

Confused now .

Paid for a electrician to test the set up thats what he done and told me .

Carnt see he has missed any thing? But i carnt see how one of the light fittings would cause this and the electrician was just going on what his testing equipment was telling him.

Paying for another electrician to come and give me most likely the same result as what else he could of done i dont know ?

He just said i was getting per light fitting when switched on 2 amps leakage and when all 6 flourecent lights on was close to 5.4 amps .
Recons a internal fault on one of the flourecents but didnt confirm which one .

He was saying that the flourecents are not realiable and led is the best option for me due to this back flow of current and discharge from these fittings as not earthing involved .

Thats the just of what i can remember he said . Was at the premises for 2.5 hours so it was as if he wasnt thorough .

But surely there must be a way of measuring current surge when switching off??

I have nothing more .....

 

[123]

I'm surprised that having spent 2.5 hours on the job he hasn't found the cause of the fault...but it could just be one of those jobs I guess.

To say fluorescent fittings are unreliable is definitely not correct. They are still readily available and have stood the test of time even in commercial and industrial environments. I've had more issues with LED fittings that I ever did with fluorescent fittings.

 

[MFS Electrical]

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 .

I think it would be wise to get another sparky to clap eyes on it it sounds like there could be something else going on here the spark could do a couple of measurements to see the exact current that the RCD trips at and go from there having not seen it I suspect either an issue with the wiring to the flouros or maybe as someone else has said cumulative leakage current is causing this tripping.

 

[Mr Karl E Taylor]

The electrician having spent two hours testing the system and the wiring has said that he believes but can not confirm that one of the flourecent lights is faulty. Thats one of the six. And it is givin a back flow of current when switching off.
He has said the flourecent is giving off 2amps of leakage whilst on .

But what about leakage when switching off ?
Having spent around the cost of a higher price led batten for a electrician to tell me the fault is in the light fittings some where but carnt tell me which one is annoying to say the least. I concluded it was a light fitting by fitting two light pendants for £3

Yes get it i am paying for his time etc etc. But no concrete answer of yes its that light fitting . Just simply it looks like one of them is causing it . But no proof as to which one.

Next option is either get another electrician in to see if he can pin point which light fitting and more costs or renew the six flourecent lights and change them to led fittings as there is nothing else at fault as the electrician has tested all of the system.
It would of been nice to have been told yes its that one light fitting out of six etc
I need to have a think whats my best option now......

 

[Octopus]

^^ how did this electrician document his time and tests?

If, and I say if he thinks its the lights, then disconnecting them 1 by 1 wouldn't have been difficult - sure more time and money - but do you want this fixed or not?

 

[Mr Karl E Taylor]

Is it true that led battens dont give out any earth leakage when new and even after a few years ? And flourecent lights to start with dont but will over time?

 

[Mr Karl E Taylor]

For the record and to clarify:

I have 6 single flourecent light fittings.
2 of the six are switched two way.
4 are switched one way.

The fault is when switching off one of the lights on the two way cicuit

And info as per previous posts on electricians findings.

My conclusion is its one of the 6 flourecents that is going faulty some how .

 

[dave274]

if you think the lights are at fault then disconnect them one at a time like Murdoch said or take them both down and try two out of the other six you've got. you're spending too much time tip toeing round it instead of getting stuck in.

 

[Mr Karl E Taylor]

I have done this already before I got a electrician out to test the system that was my reason for doing this .
Fault is intermittent .
Each one has been disconnected in turn .
Doesnt trip with two lights pendants fitted.

Electrician has put it down to capacitor in one of the light fittings been faulty causing the rcd to think there is a short .

RCD and MCBs are working and tested fine.
Switches are working and tested fine.
Sockets are working and tested fine .

Every thing disconnected and readings said I was getting a earth leakage of 2amps per light on switching on .

But nothing tested to see what readings are when switching off in case of this intermittent electrical discharge / spike from one ent fittingthe flourecent

 

[Mr Karl E Taylor]

Electrician has put it down to capacitor in one of the light fittings been faulty causing the rcd to think there is a short .

RCD and MCBs are working and tested fine.
Switches are working and tested fine.
Sockets are working and tested fine .

Every thing disconnected and readings said I was getting a earth leakage of 2amps per light on switching on .

But nothing tested to see what readings are when switching off in case of this intermittent electrical discharge / spike from one of the flourecents.
Think difficult to trace a intermittent fault like this , but it seems clear to me the fault or issue is within one of the six flourecents.

The money I have spent now and if i get another electrician out again could have paid for three up graded LED fittings.

But I know and understand why I had to get a electrician out first time just to try and narrow down and rule out certain things with testing equipment .

however looking inside a flourecent light fitting any of the components could be at fault causing this fault .
It could be from what the electrician has said the small resistor / diode inside the light fitting or the capacitor etc. Finding it could be more costly than just simply changing the lights in the first place .

Shame he can not tell me which light fitting is faulty however .

So I think I be changing all 6 of them now as most economical and best option as its all pointing to one of them at least ........................

 

[Octopus]

^^ how did this electrician document his time and tests?

?????