R1+R2 Down Lighters On A New CU?

[1strangefish]

Hi All

Changing my CU at home and going to be using it as part of my Part P assessment in Jan. Starting to go through the process in my head and can't figure how I am going to do the R1+R2 for the kitchen downlighters and the under counter Floro's?

I will need this for the Zs=Ze + (R1+R2) bit (won't I?). The downlighters are all fire rated and the can means all I have access to is L+N. The Floro's don't carry the earth down.

Some sage and wisdom would be much appreciated.

Cheers

Fish

For reference qualified to 2391.

 

[m4tty]

Where is the CPC for the downlighters, should be terminated into connector block if unused? Cant you access this to test?

 

[Doc Hudson]

You can only test what is there and what is accessible. If you are installing the lights it should be possible to access the last termination point where the cable with its earth connects to the light fitting. If the lights are already installed, it may be that boxes are not accessible. In which case you can only test the the last point of the circuit that is accessible, this may be at the light switch. Wherever you do test to, make a note in the comments box or on an additional sheet and attach it to the certificate. In the average size domestic property it can be safe to assume that if R1+R2 at the light switch plus your Ze is well below the max permitted Zs then it is extremely unlikely that the cable to the light fittings would increase the R1+R2 by any significant amount. You will not fail an assessment for not testing somethings that is inaccessible.

Doc H.

 

[m4tty]

Saying that tho. Your not goin to get an earth fault there are you if the CPC isn't connected and dl's are double insulated lol

 

[1strangefish]

Thanks Doc

Not installing the down lights as already in place, wife wouldn't be too happy with me dismantling the kitchen ceiling to get to the junction boxes that should be up there. On the under counter flourescents, I can access one of the JB's with ease but the other is in a bit of a pig position, do the same rules apply?

The assessment is with ELECSA, when doing the Ins Resistance for lighting circuits I have dimmers and transformers galore. Will it be acceptable to test L+N against earth?