How can I check that a house cct can deliver 15 amps

psommerfeld

Hi,

I want to know that a house cct can continuously deliver 15 amps (or, say, some derated amount like 12 amps) without tripping the breaker.

Is there some kind of loading device made where I can control the the number of amps that it will load the outlet with?

Failing that, what household appliance could I plug in to test it? I guess a microwave is a good start, at about 8 amps.

Thanks for any suggestions!

Peter

SD515

A 1500W space heater would be 12.5 amps. Maybe a vacuum. I believe mine draws about 12A.

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Kyle

Just because you can, doesn't always mean you should

gregzoll

All modern circuits can deliver 15 amps. Some are rated for higher, depending on the wire size. You really are not clear OP as to what you are getting at.

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psommerfeld

What does the Canadian Electric Code (or even NEC for that matter - I'm guessing they're similarly derated) say about 15A house cct derating?

Canadian Tire's highest-wattage heater is 1500W. Is there a 15% derating factor for continuous use?

Is 1800W draw for short periods allowable per spec?

psommerfeld

Hi Greg,

I have a washer that is tripping the breaker. I'm trying to determine if my cct is not delivering required amperage or if the washer is somehow drawing more than it should.

gregzoll

You have a washer tripping a breaker, then there is more than just the wash machine or laundry convenience outlets on that circuit. How many circuits are in the home, and what is the total load on each circuit. That you are going to have to do, to determine a load calculation.

De-rating has nothing to do with your problem, your problem is typical of older homes, and wiring that is done by someone that does not know what they are doing. A circuit does not deliver amps, it delivers voltage. The amps is the "load" on the circuit.

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psommerfeld

I mapped the house ccts, I put the washer on a cct which I am sure is dedicated (I mapped out all the house ccts) and it still pops. The breaker panel is new. The front-load washer always trips upon entering the spin cycle. Previously, an old top-load washer worked fine on the same cct. I would have guessed that a front-load spin cycle uses less power, but maybe not since it is high rpm.

The home uses 18 ccts.

gregzoll

You do not need to map the circuits, you need to do a load calculation on the circuits. That means sitting down with pencil and paper, adding everything that connects to that circuit. If the breaker is tripping when something runs, that means that there is either something wrong with the wiring, or there is too much load on the circuit.

You have some homework to do. You also need to get a Clamp-On Ammeter, to measure each circuit, to see what the total load is.

How old is this house, how many amps is the breaker panel, can you post a picture of the breaker panel, meter & drop.

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psommerfeld

By mapping, I meant that I know what loads are on each cct, but I have not measured the individual loads or the aggregate load at the panel.

I have a Kill-A-Watt (http://en.wikipedia.org/wiki/Kill_A_Watt) which I hope can accurately measure loads that are plugged into a receptacle which should be the case for the ccts in question.

House is 50-60 years old (no aluminum), 100A panel. Don't have pics. What is the "drop"?

gregzoll

Ditch the Kill-a-watt, and invest into a Ted 5000. You can see more effectively the particular loads, and over time, it gets better with how it reads. I use it in conjunction with the Plotwatt.com & myenersave.com websites.

The drop is from the power company to the meter. Depending on what the previous owners have done with the wiring, you may find out that there could be some questionable junctions, or additions to circuits. Only way without investing in a whole-house meter like a ted, you can use a clamp-on meter placed on each circuit. As you run stuff, it will tell you the amp load on it. Also keep in mind, depending on the panel you have, you could just have also some bad breakers.

Post a picture of the panel, meter and entrance drop, as requested before, along with model & manufacturer of the power panel.

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zappa

First thing I would do is look at the power requirements on the washer information plate. The washer may have a problem or it might require more wattage than your old unit.

psommerfeld

Thanks Greg, the TED 5000 looks pretty cool.

Anyways for now I bought a 1500 W space heater, plugged it in, verified it was actually drawing 1500 W, and the breaker didn't trip. I'd be surprised if the washer is using > 12.5A for spin.

I checked the washer manual, all it says it that it needs 15A standard cct. I haven't had a chance to check the name plate yet.

McSteve

I think this might be getting a little overcomplicated. You say the washer trips the breaker when it starts the spin cycle? Does it do it instantly when the spin cycle tries to start, or after a while of spinning? Either way, my money's on a fault in the washing machine.

psommerfeld

Yes my $$'s been on the washer the whole time. But it got me thinking of what would be the best way to ensure a cct can handle max load without trial-and-error. I think I've got some good answers to that now.

Anyways, new washer's coming on Tue ...

gregzoll

Yes, a washer has a peak amount of amps, when the pump cycles, and the motor changes the transmission direction or speed for spin. My washer spec. plate states 10 amps. On a dedicated 15amp circuit, with just a overhead light, I am fine. If you are into upgrading the wiring to #12 to make the outlet just for the wash machine a 20 amp circuit, you can do that. Keep in mind, that any convenience outlets in the laundry room can also feed off of that 20 amp circuit. You can have though a second circuit in that space if you wish for other use.

I have for my basement, a dedicated for the wash machine, a dedicated for our bar-fridge and upright freezer, and a dedicated for the outlet on the side of our panel. I went that way, so that I knew if there was any chance of needing to use either the wash outlet or fridge/freezer outlet for something like a sewer auger down there, I would have no problems. All of my dedicated outlets are 15 amp for down there, and have never had any problems. Of course, I also have a basement that is wide open, so it makes it easy to change wiring and see what has been done down there for next person.

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