I am looking for an ammeter (clamp type) that I can plug into my multimeter. I want to be able to read amperage from about 10 amps to 200 amps DC. All I can find are stand alone “amp clamps” but I want one that I can use with my multimeter. Any ideas?
Such thing exist (I have one), but they are almost impossible to find. You can get a full-fledged meter for around $50; I doubt you are going to be able to get just a clamp for much less.
Something like this?
What’s your price range? What accuracy do you need?
In auto repair, this is called a current probe. Here are some.
I would like to spend less that $50 and would like an accuracy of +/- 2 Amps. I mostly need it to check if alternators are putting out the necessary current.
Looks like I am going to need to get a stand alone type. Seems to be more cost effective.
For measuring DC amps? I don’t think so.
Check very carefully that it measures DC amps. The cheaper ones seem to offer AC amp and DC volt measuring capability, but not DC amp capability.
Similarly, I’ve thought about finding such a thing for measuring AC amps on the power mains entering my house. I’d like to record our usage. There are plenty of current transformers that encircle the wire, but they don’t clamp on - you pass the wire through them. This would be a big job.
Seems like this would be a common enough want.
You can buy snap-around current transformers. Just search harder.
If I understand Napier’s desire, it is for a device that could be clamped around the entire cable (e.g. 2- or 3- conductor Romex). That would certainly be useful for many of us, but I’m not aware of any affordable device that does that because the current flows in opposite directions in the Hot and neutral (or return) line, effectively canceling out. I wouldn’t be surprised if this problem could be overcome by measuring some subtle secondary effect, but I doubt it would be affordable.
As far as feeding the wire through an ordinary loop goes. It seems like a 5 minute job – just undo the wire clamp on one incoming wire, pull the wire through the loop, and screw the clamp back. Are you speaking of the hassle of shutting off the power upstream to do that safely?
However, if this was the hassle Napier meant, it could almost be an advantage by forcing you to put a loop on each house circuit (which would be my inevitable Phase II, anyway) The Master switch makes this fairly trivial. It took me under an hour to individually remove/inspect 26 circuit breakers in my house recently [I had a heating pipe burst years ago, which caused some breakers to be flaky due to corrosion, but the builder had used an model that nobody carried anymore. Years later, I stumbled into a case of that model on auction, inspiring this project]
So – not such a hassle, if you are comfortable with your wiring skills. (Indeed, I now wish I’d done that, and suspect I soon may) I assume that circuit breaker connections probably aren’t much different in your country than in the US
All current transformers require that only a single wire passes through the core. If you pass both wires, you end up canceling the magnetic field. We use CR magnetics snap-around current transformers, model CR-3110
Beowulff got it right, I meant current transformers around each separate wire.
As far as which hassle I meant, it was pulling the wire through the loop. My wires are pretty short and pretty heavy. I doubt I could back the wire out of the clamp and clear a transformer. This is a somewhat distant memory, but I think the conductors are almost 1/2" in diameter, and they pass through a concrete block wall inside a nipple, then exit the nipple and turn downwards and travel about 6 inches, and penetrate about 1.5" into the clamps. This vertical run is so short it’s really just a bend. The far side of the nipple is locked inside the power company’s meter panel. I got the distinct impression that I wouldn’t be able to move them far enough.
By the way, laying a small loop against the flat side of Romex would allow measuring AC current. Think of the conductors inside the Romex; they aren’t in exactly the same spot, so there is area inside the loop they form, and there would be magnetic field lines. You’d have to calibrate it somehow, or do some numerical analysis to figure out what its sensitivity should be (and I have done finite element models of magnets and their field so I guess I can see how to approach it).
Did some searching and found these models:
Chauvin Arnoux PAC21
Chauvin Arnoux PAC20
Chauvin Arnoux PAC11
Universal Enterprises CA30
Greenlee CMA-60
Because units with mV/A outputs are somewhat rare, you may find it’s actually cheaper to buy an AC/DC clamp-on meter that has a built-in digital readout.
Who the hell wants 1% accuracy?
Reported.