How to determine Live switch wire

[ARW]

+1

Timer works, job done. Timer does not work - then swap the reds over.

[ss]

Yes I have one of those.

[Roger Hayter]

You may be able to touch metal parts when the case melts though.

[ss]

Issue now sorted having identified the correct wires.

[John Rumm]

Or pick them out of your face, when it flashed over internally...

[Mike Clarke]

The Fluke 101 could be worth considering. Joe Smith ran a series of high voltage tests on a range of "cheap" (under 50 USD) multimeters and this was a clear winner after testing up to 13 KV.

Officially this isn't available in the UK but can be found from apparently reputable UK suppliers on Ebay for under £50.

It has rather limited features so might not meet everyone's needs. In particular it does NOT measure current but this has the advantage that there's no danger of putting it across the mains with the leads in the 'amps' socket because there isn't one.

[ss]

Because even for something like changing a wall socket or light switch I switch the mains off and double check with volt stick. My safety drill far outways my electrical knowledge.

[Robin]

I think John meant that you can reverse the way you use a volt stick for safety. That is, turn the circuit /on/ and use the volt stick to see which red is always live and which live only when the light switch is on.

The clever bit is remembering to turn the circuit off again before grabbing the reds to label them. But if you forget it's not always fatal, but can be memorable.

[tabbypurr]

whatever is the use in testing a multimeter to 13kV?

sounds like a meter to skip.

NT

[John Rumm]

Indeed - if you are going to test which wire is live, a non contact method is safer and generally less hassle.