How do you disconnect neon lights in sockets while doing insulation resistance test.

[David345]

Hello everyone, I was just wondering how do you disconnect neon lights from socket outlets when doing insulation resistance test, as this will effect the readings, thanks.

 

[ipf]

Leave the switches in the off position....none involved.

 

[David345]

Leave the switches in the off position....none involved.

Really, i didn't know it was that simple lol, thanks, would that be ok when doing AM2

 

[ipf]

Well, you're not actually testing the sockets, you're testing the wiring and connections, the circuit.

 

[David345]

Well, you're not actually testing the sockets, you're testing the wiring and connections, the circuit.

Yeah that's true, thanks.

 

[pc1966]

Also if you are testing L+N to E (as you would do for any vulnerable electronics like non-removable LED lights) then you won't see the neon.

 

[David345]

Also if you are testing L+N to E (as you would do for any vulnerable electronics like non-removable LED lights) then you won't see the neon.

Well that reminds me, if you were doing an insulation resistance test on a row of LED lights, would you have to disconnect them all if they had sensitive electronic parts in them

 

[pc1966]

Well that reminds me, if you were doing an insulation resistance test on a row of LED lights, would you have to disconnect them all if they had sensitive electronic parts in them

During installation you really should try and test L-N before the lights go in, afterwards you probably would just test L+N to E (connected to MET) as disconnecting and reconnecting adds the risk of introducing more faults than you might have started with.

If it is wired in T&E (most domestic, quite a lot of the rest) then the CPC lies between L & N anyway so most cable damage or faults will show up as L or N to CPC fault within the cable, or L/N to external fault back via MET if cable cut/crushed against steelworks, other cables, etc.

 

[David345]

During installation you really should try and test L-N before the lights go in, afterwards you probably would just test L+N to E (connected to MET) as disconnecting and reconnecting adds the risk of introducing more faults than you might have started with.

If it is wired in T&E (most domestic, quite a lot of the rest) then the CPC lies between L & N anyway so most cable damage or faults will show up as L or N to CPC fault within the cable, or L/N to external fault back via MET if cable cut/crushed against steelworks, other cables, etc.

Right interesting, cheers.

 

[Taylortwocities]

In the real World you will rarely do an IR test L to N except for a brand new circuit. Usually L&N To E is all that’s needed.

L to N IR tests on existing installation is fraught with hidden issues : TV Amp in lofts, smart switches and (worst) sockets with built in USB sockets. ?

 

[Mike Johnson]

The Fluke 1664 on auto mode automatically switches it self off if it detects anything connected that you have missed, not ideal, but its then down to testing at 250volts if you can't find the culprit.

 

[7029 dave]

In the real World you will rarely do an IR test L to N except for a brand new circuit. Usually L&N To E is all that’s needed.

L to N IR tests on existing installation is fraught with hidden issues : TV Amp in lofts, smart switches and (worst) sockets with built in USB sockets. ?

Not if you are fault finding, had a job RCD/MCB tripping out on 32A RFC , when spilt down circuit and testing located the damaged cable between two sockets 0meg ohms across LNE, I always check both ends same results.

 

[IAmSparkytus!]

In the real World you will rarely do an IR test L to N except for a brand new circuit. Usually L&N To E is all that’s needed.

L to N IR tests on existing installation is fraught with hidden issues : TV Amp in lofts, smart switches and (worst) sockets with built in USB sockets. ?

When you know there are accessories connected which you can't find which give a 0.00 IR reading when testing L to earth and N to earth seperately, would testing L+N together to earth give a reading in that instance?

 

[ipf]

When you know there are accessories connected which you can't find which give a 0.00 IR reading when testing L to earth and N to earth seperately, would testing L+N together to earth give a reading in that instance?

Is that a serious question, mate?

 

[IAmSparkytus!]

Is that a serious question, mate?

Yes, would have been a bit pointless and random if it wasn't!

I only ever really work on new installs and therefore do seperate L-N, L-E and N-E as I was taught and have done ever since.

I know the regs say to test between live conductors together and earth if you suspect there are devices etc in the circuit that may influence the result but cant be disconnected - this is never applicable to me, however.

I was just interested to know what effect this has when taking readings as it seems like it would help if ever carrying out EICRs on installations wired by someone else.

Sorry for asking! ?

 

[ipf]

Are you getting a bit mixed up?

You get the accessory load L-N, not L or N to earth, as you put it.
You're eliminating the load by testing simultaneously L+N to E.

When you know there are accessories connected which you can't find which give a 0.00 IR reading when testing L to earth and N to earth seperately, would testing L+N together to earth give a reading in that instance?

 

[IAmSparkytus!]

Are you getting a bit mixed up?

You get the accessory load L-N, not L or N to earth, as you put it.
You're eliminating the load by testing simultaneously L+N to E.

Yes sorry, of course. Dumb moment!