Testing Unidentified Cables in Light Fitting

[suffolkoff]

Hi,
I'm sorry if I sound stupid, but I have searched and searched and I cannot find any info in how to find out which wire is which using a multimeter on a light fitting with cables that are unidentified. I've fit light fittings before and I have enough knowledge to change them, but I just can't find info in testing wires for Live, Neutral and Earth.
I've attached a photo of the wires, two have thin coloured thread running through them (white and yellow). There is also what appears to be an Earth wire on the "cup."
Thanks!

 

[EFLImpudence]

What kind of bulbs/bulbholders has the fitting?

 

[suffolkoff]

What kind of bulbs/bulbholders has the fitting?

Edison bulbs. Please see photo.

 

[Keithmac]

The contact on the side of the bulb fitting will be neutral and contact at the bottom of the bulb fitting will be live I would say..

 

[JohnD]

The contact on the side of the bulb fitting will be neutral ...

should.

 

[EFLImpudence]

Set meter to Ohms Ω (beep if it has one)

Test meter by touching probes together to get desired result - beep or low ohms.
Remember the reading as this is the resistance of the leads.

One probe on the L(Line) contact and the other on the wire ends - find which one beeps or shows near zero Ohms plus leads measurement.
Then the same for the N(Neutral).
Then the same to any exposed metal parts - Earth.
In each case make sure the other two wires do not beep.

 

[suffolkoff]

Set meter to Ohms Ω (beep if it has one)

Test meter by touching probes together to get desired result - beep or low ohms.
Remember the reading as this is the resistance of the leads.

One probe on the L(Line) contact and the other on the wire ends - find which one beeps or shows near zero Ohms plus leads measurement.
Then the same for the N(Neutral).
Then the same to any exposed metal parts - Earth.
In each case make sure the other two wires do not beep.

View attachment 163335

So,
From L in the bulb holder to the wire with no thread running through = BEEP.
From L to the wire with white thread = no beep.
From L to wire with yellow thread = no beep.

From N to wire with no thread = no beep.
From N to wire with white thread = BEEP.
From N to wire with yellow thread = no beep.

From either L or N to the wire in the cup = no beep.

So I can conclude:
The wire with no thread = LIVE
The wire with white thread = NEUTRAL
The wire with yellow thread = EARTH
The yellow and green thread in cup = EARTH

Sounds about right, do you agree? Seems like a Canadian/US fitting?

 

[suffolkoff]

Also metal part of light fitting to wire with yellow thread running through showed readings.
Wire in cup showed no readings or beeps no matter what I did.

 

[EFLImpudence]

Yes, that sounds good.

Connect yellow thread and wire in cup to supply earth, of course.

 

[suffolkoff]

Yes, that sounds good.

Connect yellow thread and wire in cup to supply earth, of course.

Yep perfect!
Live to switch live and Neutral to neutral. All good! Thank you so much for your help! I'm really really grateful, you've honestly made my day!

 

[EFLImpudence]

 

[ban-all-sheds]

Wire in cup showed no readings or beeps no matter what I did.

So are the other metal part(s) of the light not fixed to it?

 

[suffolkoff]

So are the other metal part(s) of the light not fixed to it?

Well it's attached to the "cup" so it's strange?

 

[mattylad]

Does the third wire beep when measured to the earth wire in the cup? (you did not say).
Does it beep when measured against the body of the fitting? (perhaps at a screw or end as it may be lacquered.

It would have been helpful to those helping you had you told them the full info of what the light is, its make, model and /or a photo of the full thing.
From the label it seems to be one of these:
https://www.elsteadlighting.com/products/larkin-3-light-medium-pendant-brushed-nickel/

Which would explain why there is an earth in the plastic tube as that comes from earthing the frame below and not relying on the chain to earth it.

 

[suffolkoff]

Does the third wire beep when measured to the earth wire in the cup? (you did not say).
Does it beep when measured against the body of the fitting? (perhaps at a screw or end as it may be lacquered.

It would have been helpful to those helping you had you told them the full info of what the light is, its make, model and /or a photo of the full thing.
From the label it seems to be one of these:
https://www.elsteadlighting.com/products/larkin-3-light-medium-pendant-brushed-nickel/

Which would explain why there is an earth in the plastic tube as that comes from earthing the frame below and not relying on the chain to earth it.

Yes that is the correct light fitting in the link.