Bought myself a clamp amp meter. Am I using it wrong?

[Pioneerx01]

Bought myself a new Tacklife CM01A Digital Clamp Meter from Amazon. First test is on the bench light I have plugged into an outlet. It has 2x 32W rated CFL tubes in it. Kill-A-Watt meter reads 120V with 0.72A, however my clamp meter only reads 0.34A on AC mode. It was zeroed out before measurement. What am I missing here?

[petehall347]

Re: Bought myself a clamp amp meter. Am I using it wrong?

try the other wire .
is the meter rms ?

[Pioneerx01]

Re: Bought myself a clamp amp meter. Am I using it wrong?

Other wire is the same thing. The device is listed as True RMS.

[Pioneerx01]

Re: Bought myself a clamp amp meter. Am I using it wrong?

So I have put the clamp meter on a 500W halogen light with Kill-a-watt as well. Both read 3.6A.

[PeteS in CA]

Re: Bought myself a clamp amp meter. Am I using it wrong?

The halogen light, IIRC, will have a power factor (and a crest factor of 1.414) of ~1. CFLs have a capacitive input: lousy power factor; high crest factor. I suspect one or both of your meters isn't interpreting the complex current waveform correctly.

[petehall347]

Re: Bought myself a clamp amp meter. Am I using it wrong?

wonder if the home electricity meter can see it ?

[eccerr0r]

Re: Bought myself a clamp amp meter. Am I using it wrong?

Home electricity meters will measure true power and not the spiked apparent power. (In fact most of them will measure backwards if you backpower into the grid, but don't do this without authorization.) In the UK/Europe, I heard that PF (real power to apparent power ratio) is a big problem and devices need to have neutral PF 1:1 - meaning you won't see weird readings like this.

The Kill-A-Watt amps setting is measuring apparent amps, you may need to use the "watts" reading and divide out voltage to get "true" amps and see if it matches on a nonlinear load.

[budm]

Re: Bought myself a clamp amp meter. Am I using it wrong?

Look at your kill-a-watt meter Watts display, VA display, and PF display and see what you have and then it will make sense to you. CFL is not linear load like regular lamp. You will see VA value is higher than the Watt value due to PF.