Using Clamp Meters - Electrician Talk - Professional Electrical Contractors Forum

Voltage Hazard · 11-03-2009, 10:06 AM

I just bought a new Ideal 600A clamp meter. My old 400A meter died recently. But, now I have a question.

With my old meter, if I was measuring a 600A service that was supplied by two 350 MCM's, I would measure the current on each 350, then add them together. Now, this new meter should be able to measure the full 600A by measuring both 350's together. I have tried this, and it appears to work fine.

But, the owners manual says I should only measure 1 wire at a time. Does anyone else measure 2 wires at a time with these clamps? Or, should I stick to 1 wire like the manual says, and add them together like I did with my 400A meter?

Speedskater · 11-03-2009, 08:24 PM

My guess is that they meant:
Don't measure the HOT and NEUTRAL together.
Don't measure the HOT (A) and HOT (B) together.

nolabama · 11-03-2009, 08:50 PM

i have a 600 amp fluke clamp meter and i will measure what will fit in the clamp
why would i want to measure two wires of the same phase seperatly and add that up when my meter would do it?

Bruce Wayne · 11-03-2009, 10:09 PM

Hazardous,

You can measure as many wires together as you want, as long as they are the same phase. So, 2 350's acting as one feeder, is a perfect application. You said it worked okay, and this is why.

My guess is Ideal does not want to educate people, and that is why they say "only measure 1 wire". They don't want to say you can measure more than one, then have people try to measure a hot, and neutral together. They get fewer trouble calls if they tell you to measure only 1.