Basic Electricity For Homeowners

[Cole_Robbie]

Thanks, Worth. I forgot about this thread.

For anyone else's benefit, the question was that I just bought an air conditioner rated at 14 amps, plugged it into a 15 amp circuit with nothing else on the circuit, and it keeps flipping the breaker. The unit was on clearance because it had been discontinued...now maybe I have found the reason for that happening.

[franknmiss]

Originally Posted by Cole_Robbie

Thanks, Worth. I forgot about this thread.

For anyone else's benefit, the question was that I just bought an air conditioner rated at 14 amps, plugged it into a 15 amp circuit with nothing else on the circuit, and it keeps flipping the breaker. The unit was on clearance because it had been discontinued...now maybe I have found the reason for that happening.

I used to design electrical systems for buildings - We usually only rated a circuit at 80% of full load due to voltage drops and premature circuit breaker trips. A typical thermal magnetic breaker is really not that precise on where it trips due to temperature variations in the panel board and variations breaker to breaker. The starting current on your AC unit should be more than 14 amps as well.
So that said - A 14 amp air conditioner really needs a 20 amp circuit to operate with out issues.
That would be #12 wire and a 20 amp breaker. If your wiring is already #12 then just change the circuit breaker to 20 amps. If the wiring is #14 - you really need to run a separate #12 wire circuit to the unit on a 20 amp breaker.

I enjoy reading all your gardening posts and learn from them - I hopes this helps you.

Frank

[Cole_Robbie]

Thanks, Frank. That does help.

[dmforcier]

While you're at it, you might want to invest in a 20A fixture (outlet). They cost more - $3-4 - but are much more robust that the 99¢ contractor specials that never expect to see 15A. If it were me, I'd use a single rather than duplex outlet just so I wasn't tempted to plug anything else into it.

[Cole_Robbie]

I agree. I always buy the heavy-duty outlets, anyway. It is worth the extra money.

[Worth1]

Someone remind me please to get a 240 male three prong drier plug this weekend and a bag of Ironite.
I keep forgetting.
Worth.

[Worth1]

I'm sure in the manual of Coles AC it says connect to 20 amp circuit.

I highly doubt that my garage/shop is using anything close to 50% more like 40% or less capacity.
Most of the time zero.

[dmforcier]

Hey Worth, don't forget the dryer plug and ironite.



I hope that the two are not part of the same project.

[Cole_Robbie]

So here's another question, I took the cover off the panel to look at it for wiring the new circuit. Every once in a while, the panel made a noise. It wasn't too loud, but it sounded like a bug zapper, jedi light saber, tesla coil type of noise. I turned everything off on the circuit, and eventually deduced that it was making that noise when a window unit AC was kicking on. The AC is very small, 6,000 btu, and does not use anywhere near 15 amps. The breaker has never tripped.

Is Jedi Light Saber noise bad? Should I replace the breaker?

[Worth1]

Sounds like a loose connection.

[dmforcier]

Yeah. An arc like that will degrade the connection, to no good effect. Best case, contact will no longer be made.

If you feel comfortable doing it, try tightening the screw on the neutral (white) connection and unsnapping and re-inserting the breaker. (Assuming you have snap-in breakers.)

So is there 12GA on the big A/C circuit?

[Cole_Robbie]

There's no 12 gauge wire installed now. They only put four rooms on one circuit, 12 ga would obviously be overkill, right?

I did buy 12 gauge for the new 20 amp circuit, though.

[dmforcier]

Many electricians wire a whole house in 12Ga just so they don't have to deal in two different wire sizes. Easier and less possibility of error. 12Ga is more expensive but not that much.

[Worth1]

I think they should ban 14 AWG wire for home wiring.
As for the buzz it could be coming from the connection side of the breaker too.
This would be the side that runs to you outlets and so on.
You can turn the breaker off, this will make the terminal connection dead.
Check it too but be careful.
Then it could be the breaker itself.

[franknmiss]

Originally Posted by Cole_Robbie

So here's another question, I took the cover off the panel to look at it for wiring the new circuit. Every once in a while, the panel made a noise. It wasn't too loud, but it sounded like a bug zapper, jedi light saber, tesla coil type of noise. I turned everything off on the circuit, and eventually deduced that it was making that noise when a window unit AC was kicking on. The AC is very small, 6,000 btu, and does not use anywhere near 15 amps. The breaker has never tripped.

Is Jedi Light Saber noise bad? Should I replace the breaker?

Usually a gentle buzzing at the panel board is normal when a motor load such as an air conditioner starts. If the buzz happens during the appliance start and goes away once the unit is running normally then I would not worry about it. This is caused by the magnetic section in the circuit breaker "rattling" due to the starting current of the compressor motor. The starting current can be 4-7 times the normal or rated running current of your unit. This may be listed on the unit nameplate. As the name suggests, a thermal magnetic circuit breaker has two parts - The Magnetic section responds quickly to very high and sometime fast rising currents such as a short circuit and the thermal section of the breaker responds to currents lower near the nameplate rating that are of longer duration. Remember the purpose of the circuit breaker is to protect the wire, not the load. Worth and dm both gave good advice. Check the terminals in the panel board for tightness - a motor load "rattles" the circuit breaker connection every time it cycles and can eventually loosen the screws which is a fire hazard.
Of course switch the load breakers to off before doing this or if not comfortable putting a screw driver in an electrical panel board - open the main circuit breaker first - that is the safest way.
My answers are to long...sorry.
Frank