Electrical Wiring in the Home/multi-meter amperage reading


QUESTION: Thank you for your time, Bob. I have a 15A circuit for my gutter heat. It worked fine last season, but this season it regularly trips. Because of the snow, I can't check the cables, but I have experimented with different configurations of 3 of the 4 cables being plugged in, and it's only when a 4th is added that the breaker trips, but it does not matter which one. This leads me to believe that either the breaker is defective, that the circuit is overloaded, or possibly a loose connection. I would like to measure the amperage draw on the circuit, but I do not own an amp clamp. Can I use my multi-meter if I find the neutral wire for the circuit? I have seen $11 amp clamps, but I'd rather be able to use what I have instead of buying something for just one use (not that I haven't done that before!). Thanks again.

ANSWER: You should get the same reading on either wire.  However, you would have to disconnect it, so you may was well disconnect the black wire.  It definitely sounds like the circuit is overloaded.  Heating items usually use the most electricity. You can rule out the breaker by switching the black wire to another breaker temporarily. Can you check the wattage of the cables? Either by looking for the same item online, by reading the package if you still have it, or see if it marked on the plug?  A 15 amp circuit can't handle more than 1800 watts, and you should allow yourself a buffer, since the cables are probably on constantly.

---------- FOLLOW-UP ----------

QUESTION: Thanks for the quick reply.  I was going to measure at the panel because this os the easiest access to the circuit.  I assume I wouldn't disconnect anything at that point. If I take the reading at the panel, do I need to find the neutral for that circuit, or just place the common probe on the neutral bar?

OK.  I focused on whether a meter would work on positive or negative side, but forgot that the load would be too great for what you have, using a meter.  The maximum is usually 10 amps, and you probably have 15 amps or more.  So, you really need a clamp meter, and not a amp meter.

However, I still think you would be better off trying to figure out the amperage.  Like I said, most likely it is an overload.  You should just try to connect one or two of the cables on another circuit. I looked online, and one brand uses 6 watts a foot. So, if you have more than 300 feet, it would be an overload. This winter is colder, so if the cables are thermostatically controlled, you probably have more on at same time.
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Electrical Wiring in the Home

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Bob Sponaugle


Just about any home wiring question. (not appliance repair) I have done all kinds of home wiring for myself, including adding a new breaker box, etc. Please, questions from North America only. Please be specific with details.

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