which voltage proving unit?

Gasinspect · Mar 25, 2024

i need to purchase a voltage proving unit - i have seen Megger MPU690, Martindale PD690, and Socket and See SP400, and Fluke but difficult to compare, will need sometimes to work on 3-phase so 440+volts needed. and with the automatic ramping, is there any way to stop the 400-690v for lower rated test instruments? Any recommendations? Many thanks!

SparkyChick · Mar 25, 2024

I've got a Socket & See SP200 and it's fine.

What instruments are you testing that can't deal with 400-690v? Personally I've only ever used it to test my approved voltage indicator which can handle those voltages and since that's the only thing you should be using to prove dead, I'm just curious about what else you might be using the proving unit on.

I wouldn't bother with the SP400 as it seems it's only got that pad for non-contact testers... which you shouldn't be using to prove dead.

timhoward · Mar 25, 2024

Mine (Martindale PD90) gets used fairly rarely. You only need one if there isn't a source of power to check the tester still works after isolation, and even then I've usually already got my MFT out so I just do a quick IR test on it and check it lights up.

While I wouldn't buy a 2nd hand two pole tester, I would absolutely buy a 2nd hand proving unit, as by it's very nature it either works or it doesn't, and any instance of it not-working would put you on alert anyway.