voltage at light fitting switch off

[BES]

Evening people
At it says getting about 90v at
fitting between l-n & l-e with sw off What could be causing this all tests ok . Ir around 250 l-e & 300 l-n .
Ta

 

[fulla]

probably a dodgy switch try testing with switch wire disconnected

 

[BES]

Linked out switch still same. Its on two fittings on seperate switches in kitchen

 

[Strima]

A lot of induced voltage. Try isolating all circuits then bring them on one at a time whilst monitoring the voltage, this should give you a rough idea of where to start.

 

[BES]

Cheers strima its only when lighting circuit is on everything else off . Found it last thing today ill investigate more monday.

 

[Strima]

Someone's probably dumped an extra 20 feet of T+E under the boards and got the cables all twisted up, great for magnetising screwdrivers!!!

 

[BES]

Nothing will suprise me only went to install 2 extra light fitting in garage that was a week ago !!

 

[MarkieSparkie]

Cheers strima its only when lighting circuit is on everything else off . Found it last thing today ill investigate more monday.

This appears to be at odds with your #1 post ... do you actually mean lighting circuit OFF and everything else ON perhaps? Also what instrument are using to measure the voltage?

 

[BES]

Markiesparkie
All other circuits off . Lighting circuit on switch to light fitting off voltage between switch return and neutral or earth at fitting approx 90v. Measure with megger mft 1720.

 

[truckster]

Sounds like induced voltage as said. Have you got a low impedance (Loz) voltage meter, that should tell you.

 

[BES]

No truckster havent . How would that tell you.
Ta

 

[Spazz]

As a thought check the connections - I had this on a socket the other week - the terminal was lose giving me 120v L-N, 240v L-E and 120v N-E.
The terminal was lose creating a large resistance between the neutral terminal and cable.

 

[adamh]

I would say a bad connection on a neutral from another fitting.

 

[Spazz]

Just thinking is this a 2 way light switch? - there for this should not have any voltage on the side not being used.

Do a IR test between both switched Line terminals of the switch (with the cables attached) - someone might have put a nail through it or a fried mouse

 

[BES]

No 2way seperate switch for each fitting. Thanks for replies chaps its gave me a few things to look at when i go back. Cheers.

 

[truckster]

No truckster havent . How would that tell you.
Ta

A Loz voltage tester puts a low impedance as opposed to the nomal high impedance across the contact points which allows the induced current to drain so you get a more accurate measurement. I had a leaflet on it somewhere but can't find it. I think I got it from the Fluke website so you could have a look there.

 

[bob22]

Agree with truckster, are the switch wire and the feed in the same cable. To understand it a bit better, get a couple of metres of twin and earth connect the live and earth in a plug top leave the blue disconnected out of the plug and terminate the wires at the other end in block connectors, when the brown is live there will be a induced voltage on the floating wire(blue) it can't go anywhere until there is a bulb or resistor for it to flow to 0volts.

 

[BES]

Cheers guys understand now thanks

 

[BillyTheSparks]

Hi Bes how did you get on with this problem??

I have a very similar problem at one of my jobs, just wondered if your experiance might help me out

many thanks

Billy