Clamp on multimeter question....

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I bought a clamp multi meter to read the current draw of several things around the house so I can size a generator. I received no manual with the meter. My question is, on a 240 volt circuit do I take a reading from both 120 volt legs and add them together to get the total current draw ????
Thanks Brian
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Brian wrote:

Can you go to the manufacturer's web site and view the manual?
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No, you take the max of the two hot legs. That is the total current. For example, if you had 30A on one leg, 20A on the other, then 30A total is flowing. That is 30 on one leg, 20 on the other, 10 on the neutral. If you have no neutral, then the current is equal in both legs.
For a generator, you'd be interested in the power, which in the above example would be 240V*20A + 120V*10A
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Yes, and no. Most 240 volt devices should draw the same amount on both legs, or there is a problem. However, some appliances fed with 120/240 volt feeders, like an electric clothes dryer will use 240 volts for the element and 120 volts for the motor, so there should be different readings on each leg. A generator that outputs 240 volts will be rated in KW @ 240 volts (120 volts X 2). You could add it up either way. You could also turn on all the circuits and appliances you want to work, and turn off all other circuits at the panel, and check amperage at the mains
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Let me clarify: Make a list of the items you want to control by generator. Make 2 columns. Anything thats 240 volts, list the amperage of each leg in its own column. Anything thats 120 volts, split up and try to balance between the 2 columns. When done, add up each column. Whichever column has the highest number, thats the amperage you need the generator to output @ 240 volt. You also have to keep in mind that motors need additional capacity for starting current

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If you clamp both legs of 220 volts (or the hot and neutral on a regular circuit) you get a reading of zero. The electrical fields cancell each other out. You have to clamp just one wire.
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Christopher A. Young
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in some areas like florida gas statins are required to have generators.
but your better off not going oversize on a generator unless it runs say on natural gas which rarely fails
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You are best off buying a generator sized to run everything that you intend to run simultaneously
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Ideally. However, power cuts and gas shortages are the time to practice miserly use of as little power as possible. I think the ammeter to test appliances, a very good idea.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?ItemnumberE185
These are rather convenient. Slice the insulation the long way, and fish out the black wire, so you can ammeter measure the current in the black wire.
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On Jan 29, 5:01�pm, "Stormin Mormon"

the marked watt ratings on the device is likely more accurate than a clamp on amp meter.
quiet time at nite by using a inverter on your car for a couple of CF lights is a great thing.
if your really into getting a generator, buy 2:)
a large run everything high capacity one and a small 1000 watt quiet light weight fuel thrifty one.
my small generator gets used often, so does my 1000 watt inverter.
my 4000 watt generator has run once in the last 5 years
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An oversize generator allows you to loan power to the neighbors. Who are most likely to run hair dryers, plug in space heaters, and freezers off the end of your extension cord. And they won't say thank you, or offer to help supply gasoline.
However, with a good ammeter, you can tell who is pulling the most power. Just slice the insulation of the cord. Fish out the black wire, and clamp the ammeter on the black wire. You will get the same reading on the white wire.
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No new text?
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What are you talking about? If you put a multimeter set for AC volts across the hot and nutral you'll get 120 v. If you put it across the red and black, you'll get 240 v. Wher u gettin this info? -Cappy
On Jan 29, 2:32pm, "Stormin Mormon"

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I'm talking about reading amperage with a clamp on ammeter.
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Honda has a good site for showing surge load. Surge needs to be calculated in your decision, maybe the meter had a peak hold function to show surge.
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the larger the generator the more fuel it uses even on a small load. gasoline may be hard to get in a emergency gas stations depend on electric to pump gas.
in a emergency you can rotate loads, you dont need everything on at once.
lewave a little for a neighbor, so they wouldnt complain about the noise
for off hours a inverter on your vehicles battery is a good silent option
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Tri Fuel, www.Propane-Generators.com
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snipped-for-privacy@aol.com wrote:

Exactly! While five gallons may suffice when dealing with a drunk who took out the local light pole, it is woefully insufficient when a hurricane (i.e., Ike) shuts down every freakin' gas station for sixty miles!
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What I could never understand is why the gas stations don't have a generator to provide electricity to run their own pumps. Having operating pumps could be a windfall for the gas station.
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