Measuring load on a circuit breaker.

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Hi, Does anyone know of a way to measure the current being used on a single circuit breaker from just one of the wall outlets on that circuit?
ie; I want to be able to plug something in anywhere in the house and be able to tell from there how many amps the circuit breaker is using. thanks
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Hi, Does anyone know of a way to measure the current being used on a single circuit breaker from just one of the wall outlets on that circuit?
ie; I want to be able to plug something in anywhere in the house and be able to tell from there how many amps the circuit breaker is using. thanks
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snipped-for-privacy@yahoo.com wrote:

Circuit breakers don't "use" amps, they let amps flow through them and open the circuit when the current exceeds their ampere rating.
*************
Just take the front panel off the breaker box and snap a clamp-on ammeter over the white wire exiting the breaker. That'll tell you how much current is flowing.
This cheapy clamp-on from HF will do it for you:
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumberB397
If you didn't follow what I just wrote PUHLEEZE don't do it yourself!
Jeff
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,,,
That would be the black wire from the breaker for a single-pole (120V) circuit, the white for the same circuit should be terminated on the neutral bar.
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Do your breakers really have white wires hooked to them?
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Steve Barker


"Jeff Wisnia" < snipped-for-privacy@conversent.net> wrote in message
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Steve Barker wrote:

Yes Steve, I have a couple of GFCI breakers in my home's panel which have the white wire feeding the circuits they protect hooked to them, onto the screw terminal on each breaker marked "Load Neutral".
And, there's also a white "pigtail" wire coming out of each breaker which connects to the panel's neutral bus.
Jeff (Doing the "Told ya so dance" stolen from "Will and Grace" episode 4.09.)
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Well, after many years of working with clamp on ammeters, I guess I'll have to give them all way, and get out of the trade. Cause I sure don't remember a white wire ever coming out of a breaker. With rare exceptions, they have all been black wires out of the breakers. Learn something new every day.
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snipped-for-privacy@yahoo.com wrote:

Nope. You need a clamp-on ammeter around the wire going to the breaker.
Chris
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On Tue, 20 Feb 2007 14:42:07 -0600, Chris Friesen

What are you plugging into the outlet? The easiest method is just estimate it from the power rating of the device you are plugging in. There should be a Wattage (Power) marking somewhere on a nameplate on the device. The current will be approximately = P/120 (assuming your voltage is 120V). Example - If you are running a 1200 W space heater, that would take 10A.
If it is a motorized appliance, such as a vacuum cleaner, it will have a power factor of less than one, which means it will draw slightly more current than it actually consumes in measurable output power.
If it is a heavy duty appliance like an air-conditioner, the startup currrent may be high (almost double) during the fraction of a second that it is coming up to spead.
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wrote:

Ummm, the circuit breaker is fed by a bus ... that you cannot clamp around.
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On Tue, 20 Feb 2007 16:59:14 -0500, "Charles Schuler"

Looks like someone can't tell the difference between "to" and "from". That reminds me of the numerous people who kept confusing "inputs" and "outputs" on audio/video equipment.
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On Tue, 20 Feb 2007 16:59:14 -0500, "Charles Schuler"

Hummm, but the buss is fed by a main and that main is fed by wire that you can clamp around.
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Not in any power panel that I have seen recently.
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Charles Schuler wrote:

I think he meant that the bus was fed through the main breaker, which IS fed by a wire, usually coming from the meter base.
But, to make a meaningful measurement using that wire he'd have to switch off ALL the other breakers on that feed's side of the panel. Not a very practical solution, is it? <G>
Jeff
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No Jeff, it surely is not!
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On Tue, 20 Feb 2007 17:35:03 -0500, "Charles Schuler"

OTOH, since he's wondering about the power used on one circut, many people might suggest clamping the ammeter on the wire that feeds that circut. You know, where it comes off the breaker. I know that sounds crazy, but it might work anyway.
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Why not?
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"Charles Schuler" < snipped-for-privacy@comcast.net> wrote in message
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Charles Schuler wrote:
The circuit has one wire attached to the breaker, and the other goes to the neutral bus (assuming a 120V circuit). You can put a meter around the wire that is connected to the breaker.
Are you seriously arguing about wether a wire goes "to" or "from" a breaker? In an AC circuit where current flows both ways?
Chris
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On Tue, 20 Feb 2007 17:47:10 -0600, Chris Friesen

Consider that while current does flow both ways (or more correctly, is ALTERNATING direction), POWER goes one way. "Direction" is useful there.

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Mark Lloyd wrote:

How do you figure that? Power is a scalar quantity given by I^2*R.
Power dissipated by a load is always positive no matter which direction the current flows through the load.
Chris
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