Live and neutral reversible on light fitting?

[Gwynston]

My wife bought a chrome ceiling rose and pendant to replace the standard white plastic one (to match a new chrome light cover)

The flex it came with is very long and I need to shorten it before wiring it up. But it is not usual white flex with a brown and blue core. It's made of transparent plastic and the two cores are also transparent with silver coloured wire inside. So the whole looks like a kind of silvery flex.

So when cutting down and wiring up, I can't tell which wire is live and which is neutral. Does it matter, or can I just connect up to the feed either way round?

 

[winston1]

[QUOTE="Gwynston, post: 3629402, member: 1177" I can't tell which wire is live and which is neutral. Does it matter, or can I just connect up to the feed either way round?[/QUOTE]

You could with a multimeter.

 

[bernardgreen]

If the lamps ( bulb ) are bayonet fitting then polarity is not critical. But if they are screw in lamps then the Live should go to the centre contact and the Neutral to the screw thread. ( this slightly reduces the risk of an electric shock when changing the lamp.

Look carefully at the flex. There may be a small ridge along one side of the flex or a single strand of a different colour wire in one of the conductors.

 

[cjard]

Look carefully at the flex. There may be a small ridge along one side of the flex or a single strand of a different colour wire in one of the conductors.

Buuut.. Which does that make it? Ridge=live or ridge=neutral? I'm not certain that there's a convention, or that the factory will have followed it.

Generally, no electrical appliance you buy will care which of its wires is live and which is neutral, the only real concern is of safety in a fault or unusual state condition (such as changing a bulb with the light on. The best way to check is with a multimeter, set to the "sound" setting - it beeps when it measures very low resistance. Using this you can stick one probe on the screw thread of the light fitting, and the other probe taps each exposed end of the flex. One will beep - make that neutral.

If it's a bayonet fitting, just wire it up however you like. If the fitting has a metal body it should also be earthed

 

[bernardgreen]

Buuut.. Which does that make it? Ridge=live or ridge=neutral? I'm not certain that there's a convention, or that the factory will have followed it.

The only way to indentify which is which ( if they can be identified ) unless the flex is still connected to labelled terminals in the rose. Best option as mentioned is to use a meter to determine which conductor is connected to the screw thread in the lamp holder and then connect that conductor to Neutral

 

[PBC_1966]

Buuut.. Which does that make it? Ridge=live or ridge=neutral? I'm not certain that there's a convention, or that the factory will have followed it.

There was an old convention of the ridged conductor being the neutral (a convention which is still recognized here in the U.S.). But since flex of this type fell out of general use in the U.K., the convention has probably been largely forgotten, and if it's Far Eastern stuff, who knows what they did anyway?

As Bernard said, if it's BC lampholders it's irrelevant anyway, otherwise in the absense of some identification of conductors which can be seen at the lampholder connections, a quick continuity check is in order.

 

[stillp]

There was an old convention of the ridged conductor being the neutral

Not very rigorously followed - I'd have said the opposite!

 

[Gwynston]

Thanks for the replies.
It's actually a screw bulb fitting, so I guess I'd better get it right...

There are some labelled terminators in the rose, but I didn't take note of which way it was wired before I took it to bits, because both wires in the flex looked identical. There is no obvious ridge or markings - this flex definitely goes for style over usability!

I'll have to give it a test with a meter...

 

[kai]

Does the flex comply with UK wiring regulations?

 

[PBC_1966]

Does the flex comply with UK wiring regulations?

Isn't single-insulated flex (as opposed to insulated and sheathed) now compliant for only a few specific applications? (Christmas fairy lights come to mind.) I think it was around the mid 1970's it ceased to be recognized for general lighting pendants, appliance cords, etc.

 

[Iggifer]

This flex is clear sheath with clear insulation (I think)

 

[PBC_1966]

This flex is clear sheath with clear insulation (I think)

Ah, yes, I think you may be right:

It's made of transparent plastic and the two cores are also transparent with silver coloured wire inside.

 

[Gwynston]

Yeah, I was surprised that there was no obvious indicated difference between the two wires. As I said it is a clear plastic outer sheath and each wire within has clear insulation. And the wire is silver coloured, so you see that from the outside.

I live in Ireland, but we bough the unit in Argos,and it's sold in the UK too:
http://www.argos.co.uk/static/Search/searchTerm/455%2F3656.htm