Eubanks 9 SEER air conditioning max circuit breaker size


We hear Phoenix-area homeowners ask, “Why does my air conditioner keep tripping the breaker at the control panel?”

First off, if this keeps happening then don’t turn the circuit back on.

The circuit breaker’s job is to keep your home and appliances safe by shutting off the flow of electricity when the current flow gets too high. If it keeps tripping, something needs to be fixed.

Reasons your A/C trips the circuit breaker

If the air conditioner is the source of the tripping, it may be overheating. When an air conditioner overheats, it draws more amps (a measurement of electrical current) from the circuit.

That may be pushing the circuit past the number of amps it was meant to handle. So the breaker usually trips after the air conditioner has been running for awhile.

So now we need to know what’s causing your air conditioner to overheat.

Common causes include:

1) Dirty air filter: Dirt on the filter impedes air flow. This...

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not to beat a dead horse but i am going to install a 2.5 ton unit where a 2 ton was the mca on new unit is 15 with a max breaker size of 30.There is a 20 amp breaker installed with 12 guage wire already there and changing it would be next to impossible as its running in a crawl space with limited room and was put in during the construction.i am just wondering about breaker tripping on a hot day even with the time delay on stat. Your answer lies in article 440 of the NEC.

In it, you will find requirements for overload and overcurrent protection, wire ampacities, and other requirements.

One interesting aspect of this article is that you will find that wire ampacities can be significantly smaller than the breakers that protect them, since the breakers must not open due to startup current. The wire is sized for the current drawn during running, and not starting, and the breaker is sized larger so it does not open during starting.

Most techs oversize the...

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Before we begin, please bear in mind we are not instructing you how to do the job, the following information is intended for educational purposes only! If you are uncomfortable about doing the job please call a Heating and Air Conditioning Contractor.

Watch a 2 Part YouTube Video on Contactors here
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The contactor's purpose is to send 230 Volts to the Air Conditioning Condenser or Heat Pump compressor, crankcase heater and out door fan motor. The way it works is as follows if you have a residential system.

24 Volts of power from your thermostat is applied to the (2) side terminals of the contactor (if it is a 24 volt system, see coil voltages below) (all residential systems use 24 volt coils) assuming your thermostat is calling for cooling in the case of an Air Conditioner. In the case of a Heat Pump 24 volt power is applied to these side terminals on Heat Or Cooling.

Below is a (2) Pole...

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Originally Posted by


im a 3rd yr elect apprentice. my neighbor is having a/c trouble.

he said it only started tripping within the last yr, unit has been in for 10 yrs.

erfitz, This is a good lesson in troubleshooting for a third year apprentice. Just like a good journalist, we need to ask ourselves, who, what, when, where, and why, when troubleshooting.

You stated that the HO said the AC unit worked fine for 10 years. So, then, think about what happened, something always happened.

Ask the homeowner what series of events has led to the breaker tripping; has someone been working in the house or on the unit, has the unit been acting differently, try to get to what may have changed.

After playing twenty questions, think to yourself, what may be causing the breaker to trip. Remember that breakers are mechanical devices as well as electrical. Have the moving parts become worn due to excessive heat for great lengths of time. Is a neighboring...

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