Lighting Fault

[Chr!s]

Is not just switched neutral?

 

[sellers]

Is not just switched neutral?

Then the light would still work. Not safely though.

Best thing to do is work out what cables you have and where they go. Get a long lead out and continuity tester and go from there. Sometimes you can look at a fitting and just know, other times you have to work it out. 230v on the neutral does suspect it being missing somewhere, but whats to say its the neutral in the first place?

Go find a reliable earth and check your voltages from there.

 

[PC Electrics]

Must be pre 66 if there's no cpc.

The sheathed singles method was common throughout the 60s and well into the 70s. Personally I like it, it's efficient on cable.

 

[batty]

The reason i asked if there is a cpc is because it makes it more difficult to test if there isn't but as Peter says you can get a reliable one from somewhere else.

 

[Chr!s]

Then the light would still work. Not safely though.Best thing to do is work out what cables you have and where they go. Get a long lead out and continuity tester and go from there. Sometimes you can look at a fitting and just know, other times you have to work it out. 230v on the neutral does suspect it being missing somewhere, but whats to say its the neutral in the first place?

Go find a reliable earth and check your voltages from there.

Well, id suggest the lighting is neutral switched, go to the light that works, if neutral loop from this light is lost then that light will work and the rest wont, start from the working light i bet its the first on the radail

 

[batty]

I would be very surprised if it is neutral switched i have seen quite a few single wire systems and none have been neutral switched. Some of the lines have a built in cpc some don't problem is sometimes the line will be black and grey so there can be confusion.

 

[Chr!s]

how do you explain the neutrals at 230 V

 

[kme]

S`funny - I PIR`d a 3 bed semi yesterday, that had singles loose, with no cpc. NOT 6491 type singles; but the DI stuff - which, afaiaa, IS still available. Old crabtree, with C50 3871s; and no previous inspections.

O/P - get the meter in there, isolate the cct, and play. You can`t make it much worse..........and it can be a good way to learn. Just remember where you take wires from / to.

KME

Chris: broken neutral - light switched ON - no return path = 230V neutral

 

[sellers]

how do you explain the neutrals at 230 V

No continuity, 240v reads through lamp back upto broken neutral thus being at 240v

 

[Chr!s]

Live looped in to each light, neutral switched, all neutrals will be at 230v until switched, loose the neutral loop on the first light then all bar that one fail, and all neutrals at 230V

---------- Post Auto-Merged at 00:21 ---------- Previous post was made at 00:12 ----------

Not seen it done like this before plus the red is perminant live and the 3 Black/Neutral are also live, when I split up the neutrals I can isolate the one that is live.

He says only one red? which is permanently live, i assume its connected to the lamp, so the neutral requires switching?

 

[kme]

Not if the neutrals are distributed "normally"; and the single live is from the switch?

 

[Chr!s]

Not if the neutrals are distributed "normally"; and the single live is from the switch?

Does it sound as though the Neutrals are distributed normally lol.

Hence why i said........

Live looped in to each light, neutral switched, all neutrals will be at 230v until switched, loose the neutral loop on the first light then all bar that one fail, and all neutrals at 230V

---------- Post Auto-Merged at 00:21 ---------- Previous post was made at 00:12 ----------

Not seen it done like this before plus the red is perminant live and the 3 Black/Neutral are also live, when I split up the neutrals I can isolate the one that is live.

He says only one red? which is permanently live, i assume its connected to the lamp, so the neutral requires switching?

Well im going off what the op has said, he infers line is permanent, so must be neutral switched

 

[batty]

no the live loops go through the switches and the neutrals are looped through the lights i would think the fault is at the first light as thats the only one that is working.

 

[kme]

Ah! I see what you mean.

"Infer" - issat like "assume" :yellow card

It sounds like a non-standard bit of leccie string, which is why I suggested he go play with it to find out

 

[Chr!s]

no the live loops go through the switches and the neutrals are looped through the lights i would think the fault is at the first light as thats the only one that is working.

So the permanent line to the lamp is a fault? and also we have a broken neutral fault, okay it not impossible it will also raise the neutral to 230V, ill go with my option based on the ops description.

 

[batty]

Perhaps he has the switch on.

 

[Chr!s]

Ah! I see what you mean."Infer" - issat like "assume" :yellow card

It sounds like a non-standard bit of leccie string, which is why I suggested he go play with it to find out

Dont really know, just felt right, ill google it lol

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Perhaps he has the switch on.

Perhaps, or a fused switch, ill give the op the benefit of the doubt on this one

 

[batty]

Problem is he's not sure so he has asked on here and if you don't have a cpc to hand it makes it more difficult to test especially if some of your black cores are live and not neutral.

 

[ProDave]

Does it sound as though the Neutrals are distributed normally lol.Hence why i said........

Live looped in to each light, neutral switched, all neutrals will be at 230v until switched, loose the neutral loop on the first light then all bar that one fail, and all neutrals at 230V

---------- Post Auto-Merged at 00:21 ---------- Previous post was made at 00:12 ----------

Not seen it done like this before plus the red is perminant live and the 3 Black/Neutral are also live, when I split up the neutrals I can isolate the one that is live.

He says only one red? which is permanently live, i assume its connected to the lamp, so the neutral requires switching?

Well im going off what the op has said, he infers line is permanent, so must be neutral switched

You are a long way wide of the mark here.

The red CANNOT be a distributed permanent live, for that to be the case there would have to be more than 1 red at each light fitting to loop through to the next one.

The blacks, are all supposed to be neutrals, looping through to further light fittings, hence why there are more than one at most light fittings.

The reds are the switched live from the light switch.

The reason some of the blacks appear to be live, is because the neutral connection is broken somewhere, so they connect to live via a light bulb somewhere so obviously a non working light somewhere is turned on. If all the light switches were in the off position, the floating neutrals would have no voltage on them at all.

As has been said many times now, the fault to look for is one of the neutrals broken or pulled out of it's connection.

If simply looking at each light fitting does not reveal it, have a look in the loft. As previously suggested, someone may have accidentally pulled a cable while putting stuff in the loft, and the errant neutral may now have been pulled some way from the light fitting it's supposed to be connected to.

 

[Chr!s]

Dave

You are a long way wide of the mark here.Possibly, possibly not, im not disagreeing as such with what everyone else is saying as such.

The red CANNOT be a distributed permanent live, for that to be the case there would have to be more than 1 red at each light fitting to loop through to the next one.

Well not necessarily, if this is a DIY job then the lives maybe fed via a junction box, then only one live would be present.

The blacks, are all supposed to be neutrals, looping through to further light fittings, hence why there are more than one at most light fittings.

Yes, and this would still hold true where the live is a permanent feed.

The reds are the switched live from the light switch.

Normally yes, in this case possibly, possibly not. The op states a permanent line?

The reason some of the blacks appear to be live, is because the neutral connection is broken somewhere, so they connect to live via a light bulb somewhere so obviously a non working light somewhere is turned on. If all the light switches were in the off position, the floating neutrals would have no voltage on them at all.

The neutrals would also be live in a switched neutral. Well which ever the case, whether switched neutral or line, the neutral is broken.

As has been said many times now, the fault to look for is one of the neutrals broken or pulled out of it's connection.

If simply looking at each light fitting does not reveal it, have a look in the loft. As previously suggested, someone may have accidentally pulled a cable while putting stuff in the loft, and the errant neutral may now have been pulled some way from the light fitting it's supposed to be connected to.

Agreed