help needed for fault on lighting circuits

[fixit4u]

Hi folks

not had much fault finding experience do am asking if anyone can give me some help/advice pls, i was asked to look at a lighting fault by s plumber who said the bathroom lights where he was working had a fault on them worked then didn't work, the lights switched on with the switch so i took s reading at the switch ( megger ) it was not RCD so tested fast test, it showed 78volts and kept saying trip, i tried this at other light switched in bedroom down stairs, all shown same although were different circuits, i tested at the switch as couldn't get a test to work at the fitting itself, the rest of the house circuit's tested ok although a little high ??
any help pls ??

 

[MDJ]

Hi folks

not had much fault finding experience do am asking if anyone can give me some help/advice pls, i was asked to look at a lighting fault by s plumber who said the bathroom lights where he was working had a fault on them worked then didn't work, the lights switched on with the switch so i took s reading at the switch ( megger ) it was not RCD so tested fast test, it showed 78volts and kept saying trip, i tried this at other light switched in bedroom down stairs, all shown same although were different circuits, i tested at the switch as couldn't get a test to work at the fitting itself, the rest of the house circuit's tested ok although a little high ??
any help pls ??

oh dear
what cables did you test across and what scale were you on?
what has the rest of the house got to do with the bathroom

Have you tried checking all cables are tight in lights and no loose neutrals etc?

 

[guest119]

Call an electrician in to have a look/fix for you.

Boydy

 

[Pete999]

As MDJ mate what exactly did you test, your post is very confusing

 

[SPARTYKUS]

As above, you need an electrician on site to fixit4u, fixit4u :smiley2:

 

[Brightspark2]

Do you mean you have been doing loop impedance measurements?...

Thats not what you should be doing. Start with voltage measurements at the fitting then switch.

Only if you are competent to do so...

 

[Dan]

Keep the thread on topic lads. No need to reply to the thread if you don't have anything to say that'll help one way or another.

 

[fixit4u]

Keep the thread on topic lads. No need to reply to the thread if you don't have anything to say that'll help one way or another.

i tried to conduct a loop test at the bathroom light switch live/earth with a megger but the screen kept saying 78volts and trip , the test would not do anything at the fitting itself live/earth so thats why i tried the switch, the rest of the house lights were all the same as this although the lighting circuits were on 3 seperate breakers so was just enquiring if anyone had any advice about the problem or what fault inverigation they would have done pls

 

[trev]

Why did you start with loop tests? It's not what I'd have started with.

 

[Plonker 3]

What test equipment do you have?
What other tests have you carried out?

 

[Pete999]

More to the point, what exactly is the fault/problem with the lighting?

 

[tony mc]

Post 2 by MDJ tells you where to start try that first!!!!

 

[Richard Burns]

78V indicates that you either have a loose connection or, depending on where the voltage is measured, that there is no earth.
Because you have a fault where the lights are occasionally working a loose connection would be my favourite choice.

 

[R G]

You will need to start of with a set of test leads in this case , Loop impedance and RCD testing are what you would use once the faults are rectified , you need to trace the circuit starting in the bathroom and going back as required , until you find a starting point that is reading correctly , I would strongly recommend that unless your competent in this , this is best checked by a qualified Electrician , because the testing would involve live testing to start with,,Best of luck,,

 

[SirKit Breaker]

Test it properly. R1+R2 then IR, this should show up any faults if you do it properly. If you don't test it methodically, you will spend all day chasing your backside.

Cheers...............Howard