Clamp meter tips

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  #1  
Old 08-24-13, 02:40 PM
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Clamp meter tips

As I prepare to do a project, curiosity got the better of me and I wanted to see the actual draw on a line.

I took my clamp meter, an Ideal 736, and clamped to the hot wire, but got no reading at all.

I know the line has to be under load and only the hot line can be clamped to avoid cancelling out the reading if a neutral line is clamped too, so I had the hot water run for a few minutes, in theory, thinking after about 2 minutes, the tank would kick in and start to heat the replenishing water coming in to the tank. But the reading was zero. I did set to ohms and make sure the meter was discharged before each reading attempt.

I have used the meter with success using the probes, but this is the first attempt at clamping a live line to see the draw.

Either my theory, or my practical use, of the meter is wrong. :-(

Any suggestions?
 
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Old 08-24-13, 03:07 PM
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2 min might not be enough for it to kick in. You should let it run as you watch your meter spin (or the digital display) and when you see the draw increase then take your reading. Just to be sure I mean.

Usage seems correct.
 
  #3  
Old 08-24-13, 03:55 PM
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Thanks Vic,

I will try again when my daughter is in the shower, she has hair down to her hips and no one makes a hot water heater work as hard as she does!
 
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Old 08-24-13, 05:14 PM
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If your water heater is on a 240V circuit then it's supplied with two hot wires and one ground wire - no neutral. Yes, you still clamp around only one conductor, but I don't recall whether you have to adjust the result to get the actual draw.
 
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Old 08-24-13, 06:13 PM
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I have never adjusted when measuring trip load on window A/Cs and measuring worked okay. Always told me correctly if it was the A/C or the breaker that was bad.
 
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Old 08-24-13, 06:34 PM
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You need to adjust for three phase applications.

In 120v applications you can measure the hot wire or the neutral.....just not both at once.
 
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Old 08-24-13, 07:34 PM
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In 120v applications you can measure the hot wire or the neutral.....just not both at once.
Right, but I was asking (trying to remember) about a 2 hot, 0 neutral circuit.

I have never adjusted when measuring trip load on window A/Cs and measuring worked okay. Always told me correctly if it was the A/C or the breaker that was bad.
Right. But did it tell you the actual load? Or did it tell you half of the total?
 
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Old 08-24-13, 07:38 PM
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Since the load on good A/Cs on bad breakers matched the specs for FLA within about 10% I'd say it was actual load.
 
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Old 08-24-13, 09:21 PM
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Since the load on good A/Cs on bad breakers matched the specs for FLA within about 10% I'd say it was actual load.
Yes. Just couldn't remember whether that's what you got as the readout on a 240V circuit or not.
 
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Old 08-25-13, 04:13 AM
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Your meter was set to ohms? My clamp on meter unit outputs 0 to 2 volts to show current of 0 to 20 amps or current of 0 to 200 amps.
 
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Old 08-25-13, 07:47 AM
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I do not seem to be able to use reply with quote, is it s new member thing that prevents that?


DMCman
"Your meter was set to ohms? My clamp on meter unit outputs 0 to 2 volts to show current of 0 to 20 amps or current of 0 to 200 amps."

I read somewhere that setting the meter to ohm first, discharges the unit to be sure the reading is accurate.
I checked the manual and it actually recommends using the continuity setting to discharge the meter.
Once discharged, it was set to amps.



PJmax:
"In 120v applications you can measure the hot wire or the neutral.....just not both at once."

The manual did make mention of this. I just mentioned it to eliminate the wrong use by grabbing both leads theory.
 
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Old 08-25-13, 08:06 AM
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I do not seem to be able to use reply with quote, is it s new member thing that prevents that?
No, it is disabled for all members because people would just quote the whole post without trimming. At the top of the reply editor there is a quote bulb that looks like a cartoon speech bubble use that to set your quote code ([QUOTE][/QUOTE]) Then cut and paste what you wish to quote. Remove the refer information at the end of the copy and paste. Here's what the quote at the beginning looked like before removing the refer. Refer is last two lines.

[QUOTE]I do not seem to be able to use reply with quote, is it s new member thing that prevents that?

Read more: [url]http://www.doityourself.com/forum/electrical-ac-dc/503650-clamp-meter-tips.html#ixzz2czNLUIu0[/url][/[/QUOTE]
 
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Old 08-25-13, 08:18 AM
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I think the meter should be set to volts. The clamp-on ammeter actually acts like a transformer and inducts a voltage based on the current in the wire.

I may be wrong, it's been awhile since I've used a clamp-on ammeter.
 
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Old 08-25-13, 08:21 AM
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I have only used analog and his sounds like digital which may be self ranging. On analog i had multiple amp ranges to choose. If digital he may not.
 
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Old 08-25-13, 09:09 AM
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It it were a transformer it would only work on AC power. Mine has a battery in the probe and works for both DC and AC currents. You set the external meter to DC or AC volts to read the current.
 
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Old 08-25-13, 11:41 AM
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Any suggestions?
Your Ideal meter auto powers off after 10 minutes, did you let it power off. You wake it up by pressing any button.

http://www.idealindustries.com/media..._manual_v2.pdf

If you think the meter isn't working properly and have tried changing the battery, it does carry a full lifetime warranty and will be replaced.
 
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Old 08-25-13, 03:21 PM
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The Ideal 736 is strictly a stand alone device. It does not plug into a DVM.

I did set to ohms and make sure the meter was discharged before each reading attempt.
I'm a little lost why you would set it to ohms first before checking for amps. I've never heard of discharging the meter first. Just set it to amps and read it.
 
  #18  
Old 08-25-13, 08:22 PM
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I'm a little lost why you would set it to ohms first before checking for amps. I've never heard of discharging the meter first. Just set it to amps and read it.
That is what I had read, it was the first time I tried to use the meter's clamp meter functions, I had just used it as a probe volt meter to date.
I am interested to know what device pull what current.
 
  #19  
Old 08-26-13, 08:11 AM
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Have you read the instrucions yet?
 
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