220V Air Conditioner - Proper Wire Gauge

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Hello,
I have a dedicated outlet for a 220V window air conditioner that is connected to the main panel with 12-gauge wire and a 20-amp fuse. The label on the air conditioner says "Cooling Amps 15.0/16/5," which would lead me to believe that the wire is sufficient for the load. But, the label also says "use time delay fuse or circuit breaker 30 amp." If a 30-amp fuse is required, does this mean that I need to replace the wire with 10-gauge?
Here's the entire label from the unit: Frigidare Gallery air conditoner Model # FAS295J2A4 Serial # JK22068612 Volts 230/208 Cooling Amps 15.0/16.5 Cooling Watts 3365 3300 Cooling EER DOE 8.5/8.5 BTU 28,500 use time delay fuse or circuit breaker 30 amp
Thanks for your help! Will
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Yes. However, given the data shown below, it should be just fine with 12-ga wire and 20-amp fuses.

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Doug Miller (alphageek-at-milmac-dot-com)
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Will Godfrey wrote:

continuous loads to 80% of this maximum value so your 16 amp load is ok. The suggestion that a time delay fuse be used indicates that there is a short duration motor starting current that may exceed 20 amps. Consequently a fuse, or circuit breaker that has a delay characteristic so that it doesn't blow or trip immediately when its current limit is exceeded is what you may need. Most Square-D QO series breakers (commonly used in good residential installations and available at Home Depot) are marked HACR (heating, air-conditioning, and refrigeration) and have a delay, or inverse time characteristic.
Boden
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If you use a 30A breaker, no. 10 wire is required. At 15 A you are on the upper limit of #12. It may be OK, but it may also trip the breaker on startup. If you get voltage drops it will be even worse. I'd be inclined to change it and be on the safe side.
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What kind of plug is on the cord? Is it a 30 amp plug or a 20 amp plug? Check here for compatibility: http://www.nooutage.com/nema_configurations.htm
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John Grabowski wrote:

Checking the plug is a good idea. If the manufacturer wants a 30A breaker there should be a 30A plug and the circuit should be #10 with 30A breaker.
All residential circuit breakers are time delay. I never figured out how HACR breakers differ from 'normal' breakers.
As others have said, the 230V rating is 15A and that is actually OK for #12. If the A/C was hard wired you could use a 30A breaker with #12 wire - one of the intricacies of the code. But not for a plug-in.
As others have said, on a 20A breaker the A/C should run OK but may trip the breaker when it starts.
--
bud--

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bud-- wrote:

Looking at the spec. of the unit, 20Amp breaker with 2-12 wire is proper. Too big a breaker won't give good protection. When it supposes to trip it won't.
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Thanks everyone for your help. Looking at the plug is an excellent idea.
Here's a photo of it:
http://www.webster.edu/~godfreyw/files/P1010199.JPG
Comparing it to http://www.nooutage.com/nema_configurations.htm , it appears that it will require an outlet, wire, and breaker rated for 30 amps. Does anyone think think plug might be intended for the 20-amp 5-20R or 6-20R outlets shown in the outlet diagrams?
Thanks again!
Will

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Will, If you already have a 220 volt, 20 amp circuit it should have a 6-20R receptacle. The 30 amp plugs are bigger which judging by the prongs of the plug in your fingers is what you have.

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Thanks, John. I'm thinking that the plug is the larger, 30-amp 6-30 as well. I don't have the recepticle installed yet, just the existing wire and outlet box. Looks l ike I need to upgrade to 10-gauge wire.
With appreciatiion, Will
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Tony Hwang wrote:

current. So long as the wire gauge and breaker capacity are matched properly the size of the load is immaterial.
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Boden wrote:

Really? wire is link between breaker and the load. Current flowing on the wire is depending on load. You are trying to say breaker only protects wires, nothing to do with the load? Does not make sense to me!
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On 4/30/2008 6:46 PM Tony Hwang spake thus:

The point is that the tripping point of the breaker depends on the maximum capacity of the wires, *not* the load. Think about it and you'll see why this is so. I suppose you could say that it's more important to protect the wires, since they're what can cause fires if overloaded.
So if you have a device that normally draws, let's say, 1 amp on a 20-amp circuit, and the device overloads and draws, let's say, 10 amps, that device is going to burn up without tripping the breaker. No way to avoid it, unless the device itself is fused.
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David Nebenzahl wrote:

Who in right mind would configure/install a wire/load like that? All 3 is on a closed loop. They all interact together.
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On 4/30/2008 8:32 PM Tony Hwang spake thus:

You would. I would. We all do.
Think about it: you've got a 20-amp circuit in your house connected to a run of baseboard outlets. You've got various things plugged into that circuit: let's say one of them is a device that draws half an amp maximum. Then let's say that device overloads and draws, let's say, 10 amps: enough to blow the device, but not enough to blow the breaker. (Of course, it's far more likely that an overload will cause a direct short which *would* trip the breaker, but this scenario is possible.)
If I understand your logic correctly, then yes, we could set things up so that each load is perfectly matched to its wires. But that would mean we'd need a separate circuit *and* circuit breaker for each and every device in the house. The systems we actually have--branch circuits each serving a number of devices--is a compromise.
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Most recepticals in houses are wired with either 15 or 20 amp breakers. Look at all the devices you have in the house and see how many are plugged in that only draw a few amps.
As said above , the sizing of the breakers and wire is such that the wires are protected from getting too hot and causing a fire in the wall. The devices plugged into the recepticals should be fused to protect them.
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Boden wrote:

Looking at the spec: "use time delay fuse or circuit breaker 30 amp" If that is what the nameplate or manufacturer says the code requires a 30A circuit. One can guess that the A/C will trip a 20A breaker when it starts.

But not the way it is done for hard wired motors.
--
bud--



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Frigidaire makes thousands of ACs every day so the fact that they call for a 30A breaker is silly, right?
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Edwin Pawlowski wrote:

Even my 3.5 ton ODU is working on 20Amp with 2-12 wires.
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