How To Figure Amps On A Circuit? - Electrical - DIY Chatroom Home Improvement Forum

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Old 01-22-2010, 01:31 AM   #1
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how to figure amps on a circuit?

I have a friend who has a breaker that keeps tripping in his home panel. I dont have a clamp on meter. How do you figure out how many amps are on the circuit?
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Old 01-22-2010, 05:47 AM   #2
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buy a clamp on meter?
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Old 01-22-2010, 06:21 AM   #3
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Without a clamp-on ammeter, you might try sequentially disconnecting or turning off and on items served by that breaker and observing the breaker action. That way you can compute the load.
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Old 01-22-2010, 10:00 AM   #4
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without a meter you can only guess.
What size and type of breaker?
Could be a gcfi that is tripping on ground fault and not over current. The same with a AFCI breaker.
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Old 01-22-2010, 10:02 AM   #5
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Add up the watts of the things plugged in and turned on for that circuit and divide by 120 (by the volts).

Is it only when something that uses a lot of electricity, such as a hair dryer, is turned on?

Sometimes one circuit serves two or three rooms so you might be surprised how many items you find are drawing power from that circuit.
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Last edited by AllanJ; 01-22-2010 at 10:05 AM.
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Old 01-22-2010, 12:11 PM   #6
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Yes, turn off the breaker, then see what no longer works.

List each item and write down the watts in one column if it says watts on the appliance or amps in another column if it says amps on the appliance label.

Then total the watts. Total the amps.

Here you can convert watts to amps under "single phase"...

Then add the amps converted from the watts column to the other amps total. And you have the total amps being used.

To solve the problem, you can move some of these to another circuit.

Or run a new circuit to one big power user. Then you just need to install one outlet.
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