I Need a Plug-In Ammeter

[swpaskett]

What am I missing here? Wouldn't just about any decent multimeter do the job?

You can get fancy and build a breakout; grab an old 3-wire extension cord you don't care about anymore and strip off about a foot of the outer jacket. Cut the black wire in the middle. Put banana plugs on the cut ends (use the shielded kind if you, like me, fear doing something stupid). Plug the wires into your multimeter and the extension cord ends into your variac and hardware under test.

 

[swpaskett]

I forgot this one: use a current transformer. Coilcraft makes the one I use: CS60 Series 50/60 Hz Current Sensor | Coilcraft or CS60-010 50/60 Hz Current Sensor | Coilcraft. They will gladly sample you one. You put the appropriate load resistor across the secondary. The primary is one or more loops of wire passing through the hole in the coil, so if the sensitivity is 10A/V with one turn, two turns makes it 5A/V. Each loop of wire on the primary changes the turns ratio and you can easily do the voltage to amperage calculation based on that and the load resistor value. Again, use your multimeter (on the ACV setting) to measure the current. If short on multimeters, go to Harbor Freight and buy a few of their cheapest multimeters -- usually around $5 each -- they are surprisingly accurate for the price. I keep a dozen or so around just for this kind of thing.

 

[Audio1Man]

You can get fancy and build a breakout; grab an old 3-wire extension cord you don't care about anymore and strip off about a foot of the outer jacket. Cut the black wire in the middle. Put banana plugs on the cut ends (use the shielded kind if you, like me, fear doing something stupid). Plug the wires into your multimeter and the extension cord ends into your variac and hardware under test.

I would cut the NETURAL (White wire) this will measure the return current and the LOAD will add some current limiting in case of some type of fault.

 

[Khron]

I would cut the NETURAL (White wire) this will measure the return current and the LOAD will add some current limiting in case of some type of fault.

... But we're talking AC, so WHERE you measure the current is irrelevant.

Unless you wanna measure how much of it leaks from live to earth, but if that's anywhere near 30mA, that should trip the RCD/GFI in your electrical panel (assuming the leakage is on the non-isolated side; otherwise there's no leakage to speak of).

 

[Audio1Man]

Safety is high priory. The current is the same. I prefer the use of the WHITE wire is so the current meter voltage is near ground, not @120/240 volts.

 

[David Kulka]

If you have a DVM you can just turn an IEC cord or AC extension cable into a current test adapter by breaking the hot or neutral connection somewhere along the cable and installing 2 banana plugs at the break. Or physically separate one of those leads and loop it through an amp clamp like this, with no connection at all:

 

[SonicFarm]

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