Voltage on the Earth cable for light circuits

[welshwizard]

Any sign of KME?

heard any news yet? :| ?:|

Nothing at all Mate. Hopefully, he will be on later.

 

[steptoe]

is it a spider earth system?

how old is the installation?

are you sure its actually a fault in the lighting circuit? spider earth could be a fault anywhere TBH, stole an earth for a socket,or FCU with neon and something plugged in but not necessarily even turned on.

i'd be inclined to look at a bad IR to E somewhere, or as has been said E disconnected and floating at the V.

have you checked for a voltage at the sheath on the incomer with nothing else connected? could be a crack in the lead sheath to phase.!!!

first thing you need to do is to make good the E cont fault, then find the leak somewhere.

boy oh boy oh boy,

am i glad Im not doing this for real.

 

[YogiM]

Hi Yogi M .. welcome m8!

Just tryin to get me head round the facts here and chuck out the red herrings, so I labelled a few of your points for ease of reference?

Just want to see if I have got me facts straight?

Q1) 're v.' There are three lighting circuits are they PVC T&E or singles.. PVC T&E

Q1b) If singles are you sure you have the right pairs? L & N ?

Q2) 're i.' Is the earth continuity missing off ALL of the circuits or just one? No cont reading just voltage readings

Q3) 're ii.' Is the voltage on back box on ALL switches on ALL circuits or just some... all switches with metal back boxes

Q3b) If on several does it stay constant all all points tested. Yes

Q3c) Is the voltage present with all switches OFF and bulbs out? 50 bulbs to be removed

Q3d) When you get the voltage are ALL of the lighting circuits switched OFF at CU? All switched OFF and voltage on CPC. Tried to remove each circuit, one at a time, voltage still present, reconnect one a time voltage reappears.

Q4) 're i.' You say there is no low resistance continuity... what about a high resistance continuity.. e.g. do Ins res @ 250v from wander lead to earths? Will do when i revisit

Q5) 're iv.' Joined all the circuits together? do you mean the neutrals are all combined ("borrowed") between each other.? Could be?

Q6) 're xi.' Obviously the circuits have a non-logical arrangement. Have tried to verify which bits are actually joined together? say with an insulation resistance test between the individual conductors of the circuits with the conductors of the other two light circuits? e.g. 'L' cct1 to 'L'cct2 & cct3 etc.. Got busy chasing the fault

Q7) Are the lighting circuits looped in and out at Ceiling rose / Switches / or J-box somewhere? No junc boxes, just choc blocks with no protection

Q8) Are the cpc properly sheathed? or are they bare.. could there be a cpc touchin a live part... & with no (or high res) no fuse blow volt dropped across CPC?? Some Cpc not sleeved, MCB's haven't tripped

Mr Special Location

See answers to your questions

KItchen lights, living room are all low voltage rate lights cpc's are not connected. The connection with power, switches and lights are all bodged together on connector blocks.

There was a Earth wire connected to the Live, but i had removed that, but made no difference.

On one of the switches the cpc was cut back, i had touched that and voltage was present, a slight shock.

Tried to readjust the cpc of the lights connected to the consumer unit, that had removed the live volage on the cpc, but my FLUKE 1653, still detected voltage when doing R2 test.

 

[SPECIAL LOCATION]

There was a Earth wire connected to the Live, but i had removed that, but made no difference.

.

What? where was and earth joined to live??

how do you know there arent others ?

or had they tring to use a twin & earth as 2-way switching

with a CPC used as a switch wire. ?

 

[YogiM]

There are NO dimmer switches.

The wiring is 5 years old. Done by overseas builders, done on the cheap, Not Eastern Europeans.

There was no voltage readings on the ringmains cpc.

 

[YogiM]

The CPC on the live was found in the bathroom circuit. The place has no loft to inspect. Most of the lights are down lights, even in the bathroom. Forced the owner to change the lights to IP54 rated lights in the bathrooms.

Ceilings are all sealed.

 

[kme]

Evenin` all!

Erm - hang on a sec. I may be missing summat here - but I just read the words "voltage" and "r2 test" in the same sentence!

I speed-read the other posts (sorry if I missed this guys) but are we saying that, with ALL the lighting cct mcb`s off; voltage is present during continuity checks????

If so:

step 1 MUST be to isolate the WHOLE installation; not just the mcb`s!

I assume you`ve confirmed polarity mate??

I was tending toward Slipslap`s thought here, but your last post doesn`t seem to gel with that scenario!

Yeah, there may be 50 bulbs. I really believe that you`ll have to take `em ALL out in order to get a better idea. AND remove all energy from all ccts.

As posted by a few of my esteemed - rather you than me. Especially this week!! X( :_| :_| X( :_|

 

[SPECIAL LOCATION]

:^O :^O Just put me eyes back in!

I didn't notice some of your previous answers m8!

So we are all PVC T&E out of CU... at least thats a good point:^O

Q3c) Is the voltage present with all switches OFF and bulbs out? 50 bulbs to be removed

Q3d) When you get the voltage are ALL of the lighting circuits switched OFF at CU? All switched OFF and voltage on CPC. Tried to remove each circuit, one at a time, voltage still present, reconnect one a time voltage reappears.

KItchen lights, living room are all low voltage rate lights cpc's are not connected. The connection with power, switches and lights are all bodged together on connector blocks.

This could be a couple of faults! together..

some cpc touching something it shouldn't & circuits not independent of each other!

Re (Q3d) if you are only removing power one circuit at a time...

and you have bulbs left in, and switches in the on position,

and you have neutrals joined together somewhere between circuits...

one of the other live circuits can put a voltage back onto the one you assume is disconnected ! :|

this is the simple principle

I suspect your 80v is coming somewhere between joined circuits though bulbs or transformer acting as a potential divider between your three floors

1/3 of 240v = 80v just a hunch!

In a nutshell!

you need to diss all of the lighting circuits off at the same time do all proper dead tests to identify any anomalies with any or all of the circuits!

then rebuild back up from there!

P.S. I dont envy you!

 

[SPECIAL LOCATION]

just re-reading your answer to Q3d

Q3d) When you get the voltage are ALL of the lighting circuits switched OFF at CU? All switched OFF and voltage on CPC.

Tried to remove each circuit, one at a time, voltage still present,

reconnect one a time voltage reappears.

so with ALL of the light circuits off the voltage is at CPC?

yet you said reconnect one a time voltage reappears?

how does it re-appear if it was already still present?

OR did it go away with ALL circuits off..

If it didn't disappear I think it may even be a case of go back through FULL dead and live tests on ALL circuits.. not just lights...

and as steptoe said.. verify incoming supply first...

turn OFF whole CU and check back from basics. one circuit at a time!

 

[YogiM]

Thanks for the replies and suggestions.

You guys are right not to envy the task of taking all the lights down.

I'm going to get back in the property hopefully this week, i has started to bug me.

Thanks all

 

[SPECIAL LOCATION]

Another quick point YogiM..

have you got a second meter to check your readings against?

e.g. as well as the all the singing all dancing "proper" meter for doing calibrated readings for certificates...

I always keep an 'el cheepo' basic pocket multimeter.. (ad/dc voltages & continuity scales)

the sort you pick up for around

 

[YogiM]

I will check, with 2nd meter. Thanks

 

[karlos]

the voltage could be down to a cross neutral at a light, the circuits need the neutrals spliting into each circuit first then check all conections for crosses. the way forward without removing the flooring is take the plaster board down could be cheeper, no furniture to move.

 

[SLIPSHOD & SLAPDASH]

the voltage could be down to a cross neutral at a light QUOTE]How could this in any way result in 81 Volts on a disconnected Earth conductor ?

 

[SLIPSHOD & SLAPDASH]

Another quick point YogiM..I always keep an 'el cheepo' basic pocket multimeter.. (ad/dc voltages & continuity scales)

the sort you pick up for around

 

[SPECIAL LOCATION]

Cheap :O:O I just paid

 

[SLIPSHOD & SLAPDASH]

They are all made in China ; \ ; \ ; \

 

[SLIPSHOD & SLAPDASH]

And those old cheepy cheep cheep analogue meters are much better for testing this sort of fault .

 

[steptoe]

Cheap :O:O I just paid

 

[binky]

--------------------------------------------------------------------------------Dont know what others on here may think but if its only 2 circuits sharing the neutral and the loading is ok then put the 2 phase conductors in the one circuit breaker and the 2 shared neutrals in the same termintion on the neutral bar.

Its not ideal solution - fails segregation of circuits etc, but unless a re-wire is possible then it is the only viable option.

As a thought, I would work at the CU, disconnent every wire and test between all the circuits looking for links, including from lights to sockets. I once found such a link to RCD side of CU - I was getting 115V with RCD and MCBs off caused by low resistance between circuits.