Unexpected voltages on downlight circuit

[MickSmith5824]

Hi all

Was checking out some downlights at property. Only had half hour there and due back next week to delve into it further. Upon first one checked the first thing I noticed was just how hot this fitting was I'm not sure if the following readings would have any bearing on this. With switch on I had 240v across live and neutral but 101v on Live to CPC. With light switch off I get 46 v across cpc to neutral and 46 v across switched live and neutral. To me definately seems like have issue with CPC continuity but can't really make sense of the readings at this point. Possibly a live to neutral cross connected and or maybe cpc and neutral polarity incorrect?

 

[loz2754]

More likely a loose connection at one of the CPC terminals.

 

[MickSmith5824]

More likely a loose connection at one of the CPC terminals.

Thanks Loz. Probably is something as simple as that but can't get head around how with light switch offstill getting 46v across live and neutral?

 

[loz2754]

That is probably induced voltage from nearby cables

 

[Lucien Nunes]

If it's led or fluo then it will not necessarily 'drain' off any minute leakage / induced currents that gets into the switched line. So it remains to give a reading on your meter, a so-called 'ghost voltage'. If it's a normal meter with 10 megohms input resistance, it only takes 0.0046mA of inward leakage from an adjacent permanent line to cause that reading, which is not uncommon with longer switch cables and especially 2-ways.

And yes, the CPC serms to be open-circuit.

 

[Megawatt]

Hi all

Was checking out some downlights at property. Only had half hour there and due back next week to delve into it further. Upon first one checked the first thing I noticed was just how hot this fitting was I'm not sure if the following readings would have any bearing on this. With switch on I had 240v across live and neutral but 101v on Live to CPC. With light switch off I get 46 v across cpc to neutral and 46 v across switched live and neutral. To me definately seems like have issue with CPC continuity but can't really make sense of the readings at this point. Possibly a live to neutral cross connected and or maybe cpc and neutral polarity incorrect?

Mick I’m from the US and don’t really know how to advise you but I ran into the same thing last week and found out that it was a neutral issue. Good luck

 

[MickSmith5824]

If it's led or fluo then it will not necessarily 'drain' off any minute leakage / induced currents that gets into the switched line. So it remains to give a reading on your meter, a so-called 'ghost voltage'. If it's a normal meter with 10 megohms input resistance, it only takes 0.0046mA of inward leakage from an adjacent permanent line to cause that reading, which is not uncommon with longer switch cables and especially 2-ways.

And yes, the CPC serms to be open-circuit.

Thanks Lucien.

Mick I’m from the US and don’t really know how to advise you but I ran into the same thing last week and found out that it was a neutral issue. Good luck

Thanks Mega does suggest something going on with neutrals although think c.p.c's definately broken to. Sure I'll get to bottom of it quick enough just the combination of readings not come across before. Cheers

 

[Lucien Nunes]

Nothing you've mentioned points towards a faulty neutral. I would not consider the presence of that voltage abnormal as such. If it had been a GU10 or other tungsten light, I bet you would not have seen any voltage at all.