Lights not working after changing Lamp holder

[Carol1]

My elderly neighbours called yesterday to say none of the lights are working (its a bungalow). The man said the kitchen bulb went so he tried to change the bulb. When he did so the lamp holder was cracked so he changed the lamo holder. Now none of the lights work (I have checked the fuse and its ok). The lamp holder is not on a pendant but is loose and held in place by the rose cover. There are no terminals in the rose.
Its controlled by a two way switch.
Anyhow coming out of the ceiling is 1 red and 2 blacks (+ the earths). He insisted that the 2 blacks were in one terminal of the lamp holder and the red was in the other. Don't shout but I tested the terminals with my electricians screwdriver and the red terminal was live when the switch was on and the black terminal seemed permamently live. I have looked at all the drawings of different ways of wiring 2 way lights and can't seem to find one that matches this layout.
I checked the two switches and nothing was loose.
Does anyone have any idea's please.

 

[WabbitPoo]

Do you mean none of the lights in that room, or in the whole house?

 

[Lectrician]

Sounds like an open circuit neutral.

 

[chivers67]

I'd expect to see two reds, two blacks and two earths. One the live feed, one the switch wire whose black should be sleeved with a piece of red wire (in this instance) to distinguish this as a switched live. It does depend on how it was run in the first place.

What wires are in each of the switches and how are they terminated?

 

[bernardgreen]

I have looked at all the drawings of different ways of wiring 2 way lights and can't seem to find one that matches this layout.

It could be the live is looped around the switches and the neutral is looped around the ceiling roses with singles bringing switched live up to the ceiling roses.

For a two way system in this configuration the common of one switch has the looped live and the other switch's common provides the switched live for the lamp.

But it does seem that the neutral may be open circuit but a neon screwdriver can glow when touching a neutral if the person holding it is not at earth potential. The person can be close to live potential by capacitive coupling to nearby live wires. In the same circumstances they can glow when touching a red wire that is not live but is via a lamp connected to neutral. If you want accurate results invest in a multimeter.

 

[Carol1]

Do you mean none of the lights in that room, or in the whole house?

It's the whole house.

I can't recall exactly how the switches were terminated as I was just looking for loose connections, I willl go back and check. I do think however there was just 3 wires going to each switch.

What puzzles me is thats its all the original wiring (house is approx 30 years old) and nothing has changed recently except the chap has changed the lamp fitting and (he says!) he wired it exactly how it was before with the two blacks together in one terminal and the red on its own in the other.

 

[Lectrician]

It sounds like it is wired correctly, it sounds like it has been wired with a single core double insulated red from the switch, although I would also expect to see two reds in a terminal block at the light fitting, which are perhaps tucked (naughtily) into the ceiling void.

It could also have been wired entirely in single core double insulated, or indeed in singles in conduit.

Photos would be good.

I would be looking for loose connections on the blacks in other rooms - ignore your switches and reds for now.

 

[securespark]

The whole house? You'd expect, even with a break in the loop, that some lights would work, unless the kitchen is the first on the circuit.

How close is the CU to the kitchen?

 

[sparkwright]

The two blacks are the neutrals.

The red is the live.

And there will probably be three reds in a connector block tucked away in the ceiling somewhere.
Same with the earths.

With the power off, see if there are these reds, and check they are securely connected. Check earths while you are there.

 

[Lectrician]

Did the lights fail BEFORE someone messed with the kitchen light trying to fix things?

 

[EFLImpudence]

I have checked the fuse and its ok.

Sure ?

 

[sparkwright]

I have checked the fuse and its ok.

Sure ?

This is good advice. It may be a circuit breaker that's in the off position.

If it's a rewirable fuse the fuse would blow, it may look intact on first impressions so make sure.