RCBO Testing

[Tonyx]

Hi All,

Having just fitted some new bathroom lights for a customer, I've installed an rcbo on the existing lighting circuit, which doesn't have a cpc. Would I be correct in saying the only way I can do an rcd test on the rcbo would be to run my wander lead from the test position back to the cu, to provide an earth path for the test?

I would be grateful for your advice.

Thanks,

Tonyx

 

[holmslaw]

..

 

[Taylortwocities]

Isn't the rcbo located in the consumer unit?

Surely there's line, neutral and earth there......

 

[sparkwright]

you should be able to test the rcbo at the cu with a test lead that divides into three.

could you not have provided an earth to the bathroom lights?

 

[Tonyx]

Thanks for the constructive replies......

I should have added that I didn't know a cpc didn't exist for the full length of the lighting circuit. A 1.5 T&E leaves the cu and a 1.5 T&E appears in the bathroom lighting pendant but, between those points, no cpc in the old wiring. I have of course provided a cpc to the 3 new lights......

I guess I could test from the cu but, I was thinking a better test is from the furthest point back to the cu to give me an accurate trip time for the rcbo

I do admit to not being fully conversant with the workings of a rcbo but, I do know the test requires an earth path, hence my original question.

 

[sparkwright]

are the cpcs chopped off at all the existing ceiling roses in the house then?
could you talk the customer into reconnecting them if it's possible?

 

[VanSolo]

I guess I could test from the cu but, I was thinking a better test is from the furthest point back to the cu to give me an accurate trip time for the rcbo

Residual current devices should be tested at source, this will give the most accurate readings.

 

[holmslaw]

..

 

[sparkwright]

if you have provided a new cpc at the bathroom what is stopping you from doing the test at the bathroom like you wanted to do in the first place?

 

[Tonyx]

Just to reiteriate, a 1.5 T&E leaves the cu and a 1.5 T&E appears in the bathroom lighting pendant but, between those points, its old cable with no cpc in the wiring. I provided a cpc to the 3 new lights by running T & E to each light fitting, in case of future requirements (the new lights are class 2). So, no, it doesn't connect to earth at the moment, clever dick

For that the reason, I couldn't do my test from the bathroom....

I think the answer is .... test from source, thanks VanSolo

And to the **** from Switzerland..... no, I haven't killed any customers yet! If I was as clever as you, I could sit there all day with my dick in my hand making smart arse comments but, I'm clearly not. If you haven't got anything constructive to say, suggest you get away from the screen for 2 minutes and get a life.......... 1800+ posts, say no more!

 

[GaryMo]

Just to reiteriate, a 1.5 T&E leaves the cu and a 1.5 T&E appears in the bathroom lighting pendant but, between those points, its old cable with no cpc in the wiring. I provided a cpc to the 3 new lights by running T & E to each light fitting, in case of future requirements (the new lights are class 2). So, no, it doesn't connect to earth at the moment,

It's not compliant with BS7671:2008 then - 411.3.1.1, last paragraph. The only exemption it seems is a suspended lampholder.

What about capacitive coupling? Voltage may now appear on the unconnected would be CPC.

You should always test RCD's at source.

 

[holmslaw]

..

 

[Taylortwocities]

 

[Spark123]

Just to reiteriate, a 1.5 T&E leaves the cu and a 1.5 T&E appears in the bathroom lighting pendant but, between those points, its old cable with no cpc in the wiring. I provided a cpc to the 3 new lights by running T & E to each light fitting, in case of future requirements (the new lights are class 2). So, no, it doesn't connect to earth at the moment, clever dick

For that the reason, I couldn't do my test from the bathroom....

Now what is there to stop anyone from fitting a class 1 luminaire thinking the CPC is connected at the far end?
It is better to do the job once and do it right, wether you like it or not you have created a risk and it doesn't comply with the 17th edn regs.

I think the answer is .... test from source, thanks VanSolo

An RCD should be tested in isolation which requires it to be at source however it still doesn't get you around having installed a circuit which could easily be mistaken for an ADS one without a CPC.

And to the **** from Switzerland..... no, I haven't killed any customers yet! If I was as clever as you, I could sit there all day with my dick in my hand making smart a**e comments but, I'm clearly not. If you haven't got anything constructive to say, suggest you get away from the screen for 2 minutes and get a life.......... 1800+ posts, say no more!

It isn't his fault you don't have a clue what you are doing. The doors over there.

 

[RF Lighting]

I provided a cpc to the 3 new lights by running T & E to each light fitting, in case of future requirements (the new lights are class 2). So, no, it doesn't connect to earth at the moment, clever dick

You have also commited a criminal offence, and left the installation in a dangerous condition.

What on earth made you think you were competent to do this work in the first place?