Klein CL800

nickdearing88 · April 2017

Hi everyone. I just got a Klein CL800 (my first clamp meter), as recommended by a member here in another post. I read through the manual then checked some current readings for both AC and DC lines. It doesn't seem to be registering any current.

First I tried AC on my laptop charger from the wall outlet to the rectifier, then I switched to DC and checked from the rectifier to the laptop. Tiny changes the measurement, 0.01, 0.02, no where near accurate. It auto-ranges but I also tried switching through the manual range settings with the same results.

Next I tried larger loads AC (toaster 1000w) and DC (solar panels 6.2A per my charge controller at the time) -- no results.

I know it sounds stupid but could I be missing something. The meter seems to function normally.

Raj174 · April 2017

The clamp has to be around a single conductor. If it was, then I would suspect a meter problem.

BB. · April 2017

As Raj says--You have to separate the power lines so you can clamp on each one separately.

If you clamp on both the "Hot" and "Return" lines, their magnetic fields will cancel each other out.

If you will be measuring 120 VAC (or other standard) loads, you can make a short "extension cord", where you separate the wires so you can clamp each one individually.

https://gilwellbear.wordpress.com/category/boat-technical-topics/electrical-topics/boat-ac-topics/ground-fault-example/

Another place to experiment (in DC current mode) is with your car's battery and alternator leads. You can turn on the lights (measure the current in the battery lead), start the engine and see the charging current into the battery (and from the alternator if you can get to its wiring).

DC current clamp meters need "zeroing" (clamp not on any wiring), then clip onto the wire to measure current. They use a "Hall Effect" transistor to measure the magnetic field--Hall Effect transistors drift over time (minutes or so) and need to be re-zeroed occasionally to measure DC current flow "exactly".

AC only current clamps can use a simple (and non-drifting) current transformer to pickup the magnetic field (changing magnetic field from AC current flow).

-Bill

nickdearing88 · April 2017

Well, I'm glad I asked. How silly of me, that makes perfect sense. No wonder why it was reading zero. Every place I tested happened to be around both positive/negative leads. I guess I was too tired to have that cross my mind last night!

I just re-tested only on the "hot" leads and it worked perfectly. Thanks for the easy answers.

Horsefly · April 2017

An AC line splitter can be pretty handy in this regard. Here's one I bought for use with that same meter: https://www.amazon.com/gp/product/B0000YHN9W Plug it into the wall, plug a 120VAC load into it, and put the clamp meter through the 1x loop. You can then measure the current without separating the wires on the cord for the load.

Klein CL800

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