Troubleshooting Clamp Meter

multimeter

I have a Mastech digital clamp meter and I can't for the life of me get it to display any reading other than 0. I was wondering if there are any tricks I'm simply not aware of?

Here is what I have done:

  1. Replaced 9V battery with a brand new one (tested at 9.66V)
  2. Removed the leads
  3. Set the dial to, respectively, 20A (AC), 200A (AC), 1000A (AC)
  4. Turn unit on
  5. Clamp around a live 120V AC cable powering a desk lamp (turned on)
  6. Align cable to the guide marks to center it within the clamps
  7. Observe the reading (0.00)

I have also attempted to read AC voltage using the clamp and get readings of 0.

Finally, I have tested voltage using the leads and that WORKS, so the device itself is functional, at least partially.

Is there anything else I should be doing or do I have a defective unit?

Best Answer

You say that you put the clamp around a live lamp cord, but for a clamp meter to work, you have to put the clamp around only ONE of the conductors. If you clamp around both wires, you will not get a reading. For most situations, it doesn't matter which single wire you clamp around.

They have devices that you can plug in that give you holes to put the clamp meter:

enter image description here

Image source: Line splitter at Home Depot website

The one pictured also has a hole for a "10x" measurement. It just has 10 loops of the single wire in it so measurements taken there will be 10 times higher (good for getting more precise measurements with a less precise meter).

Or you could make one with some single conductor wire and a male and female plug.