tester light is on but it is neutral?

[bluesky]

a friend called me and said he is trying to install a ceiling light by himself, however there is one black cable is always live-- tester is aalways on, he wired this cable with another balck cable and both go to the neutral point of the light, another switch live go to the live of the light, and then the ceiling light works fine, the strange thing is why the neutral calbe looks like live? but he wired it with another neutral and looks fine? i know my friend told the truth but really have no idea about this

 

[telectrix]

if the path from the neutral at the light is not continuous to the CU neutral bar and the light is switched on, then that N will be live as there is no current flow and hence no volt drop across the load ( light ).

 

[HandySparks]

Tel has it right. Sounds like a situation I came across a while ago.

The customer had removed a light fitting and couldn't work out how to connect a replacement and asked me to do it. So I had several reds, all twisted together, and three blacks hanging out of the ceiling. I thought the easy way was to energise the circuit and test for voltage on the three blacks to find the switched line; which I found, no problem. One of the other blacks was permanently live, which puzzled me for a few minutes until I realised that one or more of the other light switches on that circuit was switched on and it was being supplied via the other lights, which weren't lit. Of course, when I connected it to the other black (the neutral back to the board) it completed the return path and all the other lights worked OK.

Sometimes the obvious takes a while to sink in.

 

[telectrix]

I thought the easy way was to energise the circuit and test for voltage on the three blacks.



WRONG. the way to identify cablers is with the circuit safely isolated then meter on ohms and get someone to operate the switch.

​

 

[electric will]

This is how people get dead.

 

[HandySparks]

I thought the easy way was to energise the circuit and test for voltage on the three blacks.

WRONG. the way to identify cablers is with the circuit safely isolated then meter on ohms and get someone to operate the switch.

Ha! I wondered whether that would rattle someone's cage, but I take your point, tel.

And I guess Will Pickard's never tested anything live?

No, it wasn't with a neon screwdriver, but a GS38 2-pole voltage indicator.

I don't mind a dig where it's merited but let's not turn this into a 10 page thread, chaps.

 

[electric will]

I test live like everyone else, I ment get dead by touching a disconnected neutral not knowing it could be at 230v

 

[HandySparks]

I test live like everyone else, I ment get dead by touching a disconnected neutral not knowing it could be at 230v

Only liable to be killed if you don't test across ALL the conductors for voltage, irrespective of insulation colour, which I do. But yes, assuming dead is one obvious way of getting caught out.

 

[electric will]

Only liable to be killed if you don't test across ALL the conductors for voltage, irrespective of insulation colour, which I do. But yes, assuming dead is one obvious way of getting caught out.

And does the original poster know this? Considering he don't know how a 3 plate light/ceiling rose works.


no offence to the op

 

[bluesky]

And does the original poster know this? Considering he don't know how a 3 plate light/ceiling rose works.


no offence to the op

how did you conclude that i dont know how a 3 plate light/ceiling rose works? again you are the wise man after someone has answered the question

 

[electric will]

Firstly I really didn't mean any offence, wise guy? I didn't know the question had been answered? I was just pointing out how dangerous neutrals can be, had one bite me once! Take it the neutrals where disconnected when ie was showing live? Surely you'd know that this is because the voltage is going through the filament in the next bulb in the circuit, returning down the neutral, to the tester which is completing the circuit?

 

[Des 56]

Asking questions and creating topics keeps the forum interesting
No doubt,if he had sat down and thought it out,the reason for the potential on the neutral would have come to him without any need for questions

Threads like this not only help answer a question,they can educate others and that is important

Live working is often condemned as being reckless and is something that electricians shouldn't do:yawn:

My veiw has always been,an electrician works with electricity and should know how to keep himself safe,whether that be working live or knowing when to do so and when not to do so,its not trying to be a lay preacher for the percieved sins of the industry

 

[electric will]

Agree with des.

 

[electric will]

I'd like to know what he means about answering the question after someone else.
i didn't answer the question until I posted post 11.
and what about the wise guy again? Do I make a habit of answer question after someone else?

 

[bluesky]

so everyone must ask wise question on this forum? will if you did not answer my question in the second post how can i know you knew the answer in the first place? then you wise conclusion is so pale to me