230v on the neutral???

[OzWiz]

Hi all,

I had a mate call today with his downstairs lights out, the MCB had not tripped. I assumed a loose connection so did not take test gear just continuity tester.

The circuit is double banked with the upstairs lights and they are fine... It's all 3plate so i checked a few pendants... This is happening at all pendants on this circuit.

*feed is live

*when the swith is made the neutral and switch live is also showing 230v to earth.

*the breaker is still not operating when this happens

I'm stumped, am i missing something obvious? The lights are all straightforward pendants with either gls or cfl's and a handfull of gu10s. No work has been going on in the house they just stopped working one day...

Please help! I'm going back tomorrow with the test gear and will just do a full test on that circuit if i can't think of anything else to do.

Cheers all...

 

[sellers]

you have a missing neutral somewhere, if the problem is at all pendant then check the neutral is connected at the board and switches (if not looped at pendants)

 

[sparkyt]

sounds like you have lost your neutral connection

 

[ADS]

Hi all, I had a mate call today with his downstairs lights out, the MCB had not tripped. I assumed a loose connection so did not take test gear just continuity tester.

The circuit is double banked with the upstairs lights and they are fine... It's all 3plate so i checked a few pendants... This is happening at all pendants on this circuit.

*feed is live

*when the swith is made the neutral and switch live is also showing 230v to earth.

*the breaker is still not operating when this happens

I'm stumped, am i missing something obvious? The lights are all straightforward pendants with either gls or cfl's and a handfull of gu10s. No work has been going on in the house they just stopped working one day...

Please help! I'm going back tomorrow with the test gear and will just do a full test on that circuit if i can't think of anything else to do.

Cheers all...

Hi,

Without knowing anything further I would suggest a break in the neutral continuity somewhere between the light that this is happening on and the CU.

You would need to work your way along the circuit testing at each lighting point N-E

until you no longer get 230v - or until you find a disconnected neutral.

This will narrow down the fault area.

It could also be that the neutral for the lighting circuit has come away from the neutral bar.

That's my take on it, anyway.

.

.

.

.

I type too slow

 

[Theorysparky]

Hi all, I had a mate call today with his downstairs lights out, the MCB had not tripped. I assumed a loose connection so did not take test gear just continuity tester.

The circuit is double banked with the upstairs lights and they are fine... It's all 3plate so i checked a few pendants... This is happening at all pendants on this circuit.

*feed is live

*when the swith is made the neutral and switch live is also showing 230v to earth.

*the breaker is still not operating when this happens

I'm stumped, am i missing something obvious? The lights are all straightforward pendants with either gls or cfl's and a handfull of gu10s. No work has been going on in the house they just stopped working one day...

Please help! I'm going back tomorrow with the test gear and will just do a full test on that circuit if i can't think of anything else to do.

Cheers all...

Downstairs neutral fault

worth checking from where the landing light is fed from....

R1 Rn downstairs lights with switches on

 

[Evans Electric]

Sounds like the neutral is not connected.

 

[OzWiz]

Thanks guys,

I've never come accross that before... Sounds like everyone else has tho... I suspect it must be between the DB and the first pendant as it effects the whole circuit...

Cheers!

 

[ProDave]

Did you actually look inside the CU?

Over tightened neutral screw and wire snapped off is my bet.

 

[batty]

Did you actually look inside the CU?Over tightened neutral screw and wire snapped off is my bet.

Be careful if it is broken off as you need to isolate circuit first probably best to switch box of totally you don't want to get a belt off it.

 

[OzWiz]

Did you actually look inside the CU?Over tightened neutral screw and wire snapped off is my bet.

I did have a brief look, didn't see anything out of place but it was pretty busy in there. I'll start at the DB tomorrow and i'll let you know. Thanks again...

 

[SteveH37]

he done any DIY recently that could have damaged a cable somewhere?

 

[sparkytim]

If neutral not dis in C U then look in first ceiling rose if loop in wiring or JB

Must be Neutral out somewhere as all above have said

 

[OzWiz]

Respect to all the knowledgable folk on this forum. It was, of course, a broken neutral at the DB due to an overtightened terminal. I shall not forget it.

Thanks, again...

 

[batty]

All part of the learning curve we are all learning all the time.

 

[Nicky Tesla]

Live comes from the DB to the lampholder down and back up from the switch through the lamp and out to the neutral.......If the neutral does not have continuity back to the DB then the neutral on the lamp side will remain live until continuity is resolved.

 

[Lurch]

Live comes from the DB to the lampholder down and back up from the switch through the lamp and out to the neutral.......If the neutral does not have continuity back to the DB then the neutral on the lamp side will remain live until continuity is resolved.

Yep, if it's not connected to the neutral bar on the CU, and in turn the neutral terminal on the service head, it isn;t a neutral, it's a blue cable that is actually live.

Just take a step back and think about things.

 

[Andy™]

which is why both line & neutral are live conductors

 

[PBC_1966]

[quote name='Andy

 

[Lurch]

Only by more recent BS7671 definition though. The Regs. never used to classify a neutral or other earthed circuit conductor as live.

And by more recent you mean 15th\16th\17th?

 

[PBC_1966]

Yes, sometime after the 14th edition. I can't remember if it changed for the 15th edition or not until the 16th, and I no longer have a copy of the 15th edition to check.

This is the definition from the 14th edition:

Live. In relation to a conductor, means that under working conditions -(a) a difference of voltage exists between the conductor and earth, or

(B) it is connected with the middle wire, common return wire, or neutral wire of a supply system in which that wire is not permanently and solidly earthed.

NOTE.- For the purpose of these Regulations an earthed neutral conductor is deemed not to be a live conductor (see also definition of Neutral conductor, and Note to Regulation 3).