How to test continuity

[Deleted member 122708]

Please can you help a complete novice.
I have a light fitting with three clear wires. No colours, textures or codes. I’m trying to establish the L, N wires.
I have a digital multimeter (see pics)
Can someone tell me what to do step by step in layman’s term please?
Which ohm do I set it at?
Where do I attach the red and black prongs?
Please Help!!
Many Thanks in advance

 

[jackhammerJIM]

Is it bayonet cap or edison screw ? Hold one probe against the earthed metal casing whilst testing against the 3 clear wires until you get a low ohm reading to identify the earth .

If bayonet cap polarity does not matter .

If edison screw repeat step one with the middle prong inside the lamp holder . This must be the Live connection .

If you do not understand any of this it would be advisable to use a professional .

 

[Lucien Nunes]

For convenience, use the continuity setting O))) which will beep when contact is made. To check that the connection is solid, use the 200Ω range. A good connection will indicate a resistance within a few tenths of an ohm of the reading you get with the probes touching together.

 

[Deleted member 122708]

Is it bayonet cap or edison screw ? Hold one probe against the earthed metal casing whilst testing against the 3 clear wires until you get a low ohm reading to identify the earth .

If bayonet cap polarity does not matter .

If edison screw repeat step one with the middle prong inside the lamp holder . This must be the Live connection .

If you do not understand any of this it would be advisable to use a professional .

Thank you so much!
It’s screw fittings.
I inserted black probe into screw fitting.
My readings are 0.00
0.03
And no reading
(Please see new pic)

So is the 0.03 reading the earth?
Which is Live?
Thank you so much!!!!


[automerge]1570538625[/automerge]

For convenience, use the continuity setting O))) which will beep when contact is made. To check that the connection is solid, use the 200Ω range. A good connection will indicate a resistance within a few tenths of an ohm of the reading you get with the probes touching together.

Thanks so much!
I got the following scores when used sound:
3
37
No sound
Please can you tell me which is earth, live, Neutral?
))

 

[Dustydazzler]

Having a meter with a bell buzzer makes basic continuity testing easy

 

[Deleted member 122708]

Having a meter with a bell buzzer makes basic continuity testing easy

I have a beeping dial.
One wire makes no sound (is this neutral or earth)
One makes loud sound with number 37( is this live)
One makes sound with no 3 (is this earth?)
Thank you

 

[James]

Ok, on the meter, just above the ohm symbol, there is a sounder symbol.

When you touch the probes together you should hear a beep.

This beep confirms that there is an electrical connection between the 2 probes

Step 1
Take all the lamps (bulbs) out of the fitting

Step 2
Place one probe on the metalwork of the light fitting
With the other probe, try each of the 3 wires in turn until you hear a beep.
That wire is the earth wire.
Mark it with some masking tape and a letter E

Step 3
Place one probe on the metal you can see directly down the center of where you screw the lamp into
(Assuming it is a screw in type lamp)
Use the other probe on the remaining 2 wires in turn
The wire that causes the beep is the live wire
Tape and mark L

The other wire by deduction is the neutral and can be checked by probe on screw thread of fitting and other probe on last wire.

IF IN ANY DOUBT, CALL SOMEONE YOU KNOW IS COMPETENT.

 

[Spoon]

Hi @Joanie .

This is going to sound very negative but this light is something that has been bought second hand and is powered by the mains. If the testing goes wrong then you or someone else could get hurt.

Step-by-step instructions are not allowed to be given out on this forum. (Everyone will interpret this differently.)

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If you do not have the know-how to do basic continuity testing then I think, for safety sake, it would be better to get someone else to test the light.

 

[telectrix]

echo last 2 posts. time to call in a spark or at least a competent person.

 

[Midwest]

Sometimes those wires have a very fine coloured thread inside them, identifying each one.