Measuring A/C current

Nov 20, 2017 16 Replies

I'm trying to find out what current my space heater uses. Says 1500 watts; that's about 12A. I have a clamp-on current meter. Is there a trick to using one of these on a power cord or do you have to have some kind of adapter to split the power cord lines?



Any way to do this to make it simple? I have some other thinfs, like a radio, that I'd like to measure too. (Trying to run my space heater and a radio off the same receptacle.)



TIA



The easiest way it to just use one of those heavy duty extension cords that look like great big zip cord (sold for A/C units). Them you just split out one of the conductors. The advantage is it is still an extension cord. A short one is going to be cheaper than that adapter.

On 20 Nov 2017 13:45:36 GMT, KenK wrote in

Get yourself one of these

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they sell them in most big-box stores.

Is there a trick to

It won't work if you clamp around the full cable.

A clamp on current meter must be clamped around only one of the wires in the cable. You could modify an extension cord by splitting the wires apart so you can clamp ONE of them.

the radio shack meter I have came with an adapter to do this

mark

That's what I did. The heater probably draws too much current for long term use on a normal #16 extension cord, but it's OK just long enough to measure current.

The cords I am talking about are 14 or even 12ga. This one is 20' but you can get 3' ones

Or get a KillaWatt meter, so you can test anything with a cord and plug. Also, it measure power, ie it accounts for power factor, not an issue in a pure resistance heater, but if it's a blower, motor load, power supply, etc, it makes a big difference. Measuring amps with those wont give you power.

snipped-for-privacy@aol.com posted for all of us...

I have always used a line splitter, that way it can give a 10 times measurement. Or a killowatt

've only read a dozen out of the50 or so replies, so don't know if it's been mentioned, but this is _exactly_ what a "kil-a-watt" plug-through meter is used for.

KAWs are widely available for about $30 - including at such places as HomeDepot, Bed Bath and Beyond, and... and Harbor Freight.

Advantage of HF is there are 20 pct off coupons available pretty much everywhere.

[snip]

At the time, The Killawatt had a big disadvantage, it was not here. I did have an extension cord and a knife (to separate the conductors).

[snip]

Why do you need 10 times? Meter granularity not good enough?

If I need to get down in the grass I would use my Fluke 8060 that is good for 1.999a or less but I seldom need that kind of accuracy.

KenK wrote in news:XnsA83344C575B1Finvalidcom@130.133.4.11:

Using line splitter, I found my Ideal Split-Jaw Smart-Meter clamp-on meter will not read less than 0.6 A. so can't measure my radios' curret usage, but measured the heater's 12.5 A OK. I think it is around 500 mA. Ideal is the first eter I've had that had a minimum measurement cut-off. I can unerstand maximum but...

I think my UEI goes down to .1a but to be frank, if the current is that low I really do not care. If I was really interested at that point I would use my Kill a Watt or the Fluke "in line" meter that gets down to 100s of micro amps. You will also find a radio or anything else with an amp in it responds to the volume control. The louder it is the more current it draws.

Instead of just one turn, put more turns through the jaws. Devide the current shown by the number of turns.

Ralph Mowery wrote in news: snipped-for-privacy@news.east.earthlink.net:

Ahhh! I didn't know that! Makes sense though. I'll have to remember that trick!

That trick also works with ferrite beads when you are limiting common mode noise.

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