Proving a point - for real

[pc1966]

Today I went to fix a minor loose screw on something and after switching off, etc, got out my Martindale VT12 continuity & voltage tester and proving unit - and my tester failed.

Yes, one LED lit, but no sound nor any of the voltage indicator LEDs functioning. So bin for that tester now. Thankfully I also had a simpler TIS one in the car so that got used instead, but it is a useful warning that even a modern tester, lightly used and in physically good condition, can randomly fail! Not good when your life depends upon it, and a reason why you should always prove your tester is working..

 

[baldelectrician]

You can also use a insulation tester at 250V to prove your hand held tester, cheaper than buying another proving unit.

 

[buzzlightyear]

I always carry a spare just in case the batteries run out.
That's a diglog..

 

[Marvo]

C'mon admit it, I won't judge you. This is where the ol' trusty neon screwdriver makes a cameo appearance. You can prove isolation and tighten the loose screw all in one well choreographed movement.