A quality clamp on meter is VERY accurate, and they are used all the time by
professionals to measure current. That's how large currents are measured.
Here are some examples
http://us.fluke.com/usen/products/ca...(FlukeProducts)

A $30 Radio Shack meter could be good or could be bad, but I wouldn't trust
it personally.

--

Mike S.

"David Combs" wrote in message
...

Question: are the clamp-ons at all accurate, or are they
(sometimes) GROSSLY wrong?

EG I got a radio shack 2part vom that had a plug-in clamp-on
coming with it. (maybe $30 when I got it 3 or so yrs ago)

David