FWIW, Harbor Freight has some really cheap, serviceable clamp-on
ammeters. They won't give you all the information a wattmeter would
(especially when power factor is important) but they can nonetheless
give you some pretty good clues at very low cost.


My appretice had a cheap meter. We used it on a service call. We
turned the power off at a breaker marked for that unit and checked it
with his meter. It showed 0 volts. I started disconnecting a wire and
got lit up by 240 volts. We tossed his meter and got mine. A cheap
meter can kill you, it certanly will not give you good answers. I have
seen many times that cheap meters lie to you (not accurate) but his was
the worst.

If you are measuring anything, good tools will give you better answers.

Stretch