Neutral is LIve?!

[mini-si]

hi all, need some input/advice on a problem i was called to this evening.
Went to a doemestic property to find new split/split board and rcd tripped( not resetting)
the client said it was when she went to turn on the upstairs lights.
therefore i found which breaker was feeding upstairs lights turned off breaker, reset the rcd all ok. so my first thought was neautral in wrong n bar and guess what it was. moved to correct position and turned breaker on but took the rcd out. any way only had my voltage tester with me to night and tested for correct voltage. to my amazement i found 230v between n-e. i deconnected the suspect neutral from the board and still 230v across N-E. every breaker off apart from the one circuit in question, when i turn circuit off voltage goes from neutral.
I left circuit disconnected night as time was getting on and made sure all was safe.
without investigating any futher and obviously it stuck in my head and thinking, only thing i can come up with is cross polarity between L-N in one of the light fittings installed by the owner(handyman) causing this voltage?

any thoughts guys

 

[Amp David]

If you have a borrowed neutral from another lighting circuit will cause this problem.

Turn off all the lights in the house and see if the RCD will reset.

 

[Johno]

if the landing light has took a live from the downstairs lights and a neutral from the upstairs lights this will trip rcd, if light (or other lights) are on and neutral is disconnected you will get 230 on neutral, i am new on here how do i start a new thread

 

[acat]

If I read your post correctly every other circuit was off and neutral was still live if that is the case Im with you for cross polarity.


Chris

 

[Amp David]

if the landing light has took a live from the downstairs lights and a neutral from the upstairs lights this will trip rcd, if light (or other lights) are on and neutral is disconnected you will get 230 on neutral, i am new on here how do i start a new thread

Go to whichever forum you want to post your message in the click on the 'Start New Thread button' at the top left.

Good luck

 

[acat]

Forgot to mention check the way the switchs have been wired.


Chris

 

[mini-si]

i got 230v on the neutral bar to start with the disconnected to stil find it was live, so the only way to over come this problem is to put both upstairs and down on same side of board?

only thing i can think is crossed polarity,b ut just trying to cover all corners and get other peoples views on this before i return tomorrow, thanks for the replies guys. much appreciated

 

[solo2771]

im with acat, has someone put new cu in? if so check tails and all circuits good luck
paul

 

[mini-si]

check whole of board polarity is fine else where, can only think wronly/badly wired upstairs lighting circuit

 

[Dobbo]

Had similar problem and it turned out that the guy who owned the property had changed the landing light and connected all the brown wires together and all the blue wires together. Unfortunately not everyone puts the brown sleeve on the switched live. Took about an hour to find it and it was only because he mentioned he had changed the light before hand made me look. Mr DIY strikes again.

 

[Jason Smith]

Check they have got the correct three conductors from each cable, and have beenput in their relevant slots. Next check is the switch wire connections at the ceiling roses. Customers are often embarrased to tell you they have been tinkering.......

 

[mini-si]

Check they have got the correct three conductors from each cable, and have beenput in their relevant slots. Next check is the switch wire connections at the ceiling roses. Customers are often embarrased to tell you they have been tinkering.......

exactly my thoughts, as this customers seems more keen than most as to what the problem is, i.e he is probally thinking is it something ive done

 

[Jason Smith]

They just love putting the black or blue wire from the switch into the black or blue terminals in ceiling roses. Hope they never make proper coloured switch wire as it will cost all of us loads of call outs each year. You may have to do a bit of continuity testing tomorrow to find which the switch wire is, as they may have been muddled up for you. Bit of brown sleeving, and your done.

Quick question, if I have corrected a fualt in a switch wire in the old colours, i.e black switch line, do I have to sleeve it in red ? or can I use brown.

 

[bugsy]

Check the switches , it is possible that the cpc on the swich lines is touching switch return on switch, (im assuming you have dissconnect the earth!

 

[Risteard]

Hope they never make proper coloured switch wire

They do make twin brown and made twin red before that.