continuity of cpc

[flukey]

hi all,
got some testing to do where there are some large expensive looking light fittings that i would rather not remove for testing

what methods do you use to get round this problem as i dont want to get caught up in an only fools and horses type moment

cheers in advance

 

[Spudnik]

If you are just checking cpc continuity then easiest way would be a long wander lead connected to MET or cpc bar in cu and to your then use the other to probe the fitting, assuming they are metal of course.

Or temp link in cu from mcb to cpc bar. then on to light fittings with switches on and probe fitting and try and get other probe into lamp holder for R1.

 

[flukey]

hi jason.
need to get decent r1 r2 reading without dismantling but although fittings look expensive i dont think they will be metal construction

 

[Spudnik]

Are the circuits looped at the switch or behind the fitting?

Sounds like a difficult situation you have.

If its for a PIR then you may have to mark it done on the test sheet as a limitation explaining why.

Other than that, im afraid your only other option is to take the fittings down, or maybe get the client to do it?

If you explain the reasons why, you may find them fairly accommodating.

 

[flukey]

looped at the fittings, just my luck

better check my insurance is up to date first then.

cheers for the reply

 

[WarrenG]

Like Jason said ask them to take down the fitting only so that you can test (they don't have to touch the electrical side) or alternatively explain the work that has to be carried out and get them to sign something to cover you for any damage that may result in the removal of the fittings?

 

[mrloy99]

hi jason.
need to get decent r1 r2 reading without dismantling but although fittings look expensive i dont think they will be metal construction

can you not use one of them lightmates that everyone was talking about?
Its unlikely that you will have to dismantle the fitting.Most have a sort of cowl covering the ceiling rose,just drop this down to access connector block.Or maybe its on the landing and you can access ceiling rose/jb from roof void.Or maybe it DOES have an only fools and horses type winch.Are you sure that this fitting is at the end of circuit?

 

[flukey]

hi mrloy. its ground floor lighting and all the lights have same sort of fitting. cover not removable. the 2 screws going through cover are holding the light to the ceiling.

 

[mrloy99]

hi mrloy. its ground floor lighting and all the lights have same sort of fitting. cover not removable. the 2 screws going through cover are holding the light to the ceiling.

Recording as LIM sounds like the way foreward then if its a double insulated fitting,and you can't get to the earth.Maybe you could take your reading at the switch,if you don't want to risk the fitting.

 

[flukey]

funny you should say that mrloy, just flicking through gn3 and noticed on page 35 that the r1 r2 reading is in fact being taken at the switch.

never noticed that diagram before because ive always taken reading at the fitting as that was the way i was taught, but thinking logically the switch would be the extremities of r1 r2 would it not.

would certainly make my life easier

 

[Spudnik]

At the switch is fine.

You could also do the loop test using 2 wire method if the MCB will hold.

Could always swap it out for something bigger if not whilst you do the test.

I thought you needed to get behind the fitting.

Wander lead will only be any good if they are metal fittings and not class II

 

[flukey]

hi jason.
never said i needed to get behind the fitting, just asked for alternative methods like the one thats now been highlighted.

we were advised against testing at the switch even on my 2391 but thinking about it logically the switch is the furthest point and if you get continuity reading there then all is well in the fitting.

obviously would wander lead the fitting as well if it was needed, but now i am questioning why we are taught to test at the fitting at all

can open, worms everywhere

 

[Spudnik]

hi jason.
never said i needed to get behind the fitting, just asked for alternative methods like the one thats now been highlighted.

I realise that now ive re read your OP

What you say about testing at the switch and it being fine at the fitting is not always the case, however if you test EVERY switch and you are sure its the last switch on the circuit then you can be sure all is ok.

Exactly the same as testing at the last fitting.

 

[whensbait?]

ive had a similar problem before, the switch isnt usually the highest r1r2 value as the switched live at the fitting adds those extra few metres from the switch, but wouldnt have thought it would be by a very noticable amount? well not enough to go through the hassle of removing fittings. is this end of line?

 

[flukey]

thats exactly how ive always seen it whensbait. i reckon thats another cock up in gn3 but it would certainly be the way to go in my predicament.