12,000 btu window unit

buenf · 07-19-2008, 01:53 AM

i have an a/c that is a 110 and mostly everytime it trips the breaker (20amps) when the compressor turns on . i have allready left the unit with its own plug . any suggetions

**Wozer** · 07-19-2008, 05:35 PM

the fact that it is on its own plug means nothing....unless by some very small chance that plug is the only one connected to the breaker...when I had my house built 7 years ago I had one plug installed with a dedicated breaker for recording use...and I paid extra for that...

the point is that its what is connected to the other plugs on the breaker that most likely matters....or perhaps the breaker is starting to go...I did a quick Google search for ac units with the specs you vaguely list and it appears as if they all fall within the ratings of a 20 amp breaker...but know this, the biggest draw that unit will give is just when it starts up, and the load it pulls may be towards the limits of the breaker just by itself...if you have another high amperage piece drawing electricity at the same time, then that is most likely the real cause...next time it throws a breaker figure out by deduction what other items are also on that circuit and deduce what item is also drawing a lot of amps....

**mack1** · 08-05-2008, 08:20 PM

Hi buenf,

Wozer's advice is good. Wall plugs are usually connected with several on the same feed (breaker). Number 12 wire is used to wire 110 volt circuits and it is rated for 20 amperes. Do NOT entertain the idea of using a larger breaker. Breakers are rated for the wire, so that the wires won't overheat and cause a fire.

A loose feed wire connection in the wall plug can cause the a heavy load to throw a breaker. Feel of the wall plug cover and see if it feels hot when it throws the breaker. If so, it is an indicator that the wire to the plug is loose.

If you turn off the airconditioner and then immediately turn it back on, it will throw the breaker. It will still have pressure on the high side of the pump that has to be overcome at start, thus causing overcurrent. If you turn it off, wait about 30 seconds before turning it back on.

For test purposes, you could try using another circuit (in another room) using a long extension cord. A 12 guage would be best, but you might get it to work with a 14 guage. (larger number is smaller wire) Borrow one from a neighbor or friend if you don't have one.

The problem could also be the Start Capacitor in the unit. It is used to shift the phase of the current during start for heavy load. After start, a run capactor is switched in for best run phase shift characteristics. If you changed out the capacitor yourself, it would be $10 or less. Cost a lot more if you had someone to do it.

If you find that the unit kicks out other breakers using the extension cord, it is probably a start problem in the unit. One ton units are't that expensive, so it might be time to replace it unless your like the idea of replacing the run capacitor.

Hope this helps,
Mack1

07-19-2008, 01:53 AM	#1 (permalink)
buenf Registered User Join Date: Jun 2008 Posts: 31 OS: xp	12,000 btu window unit i have an a/c that is a 110 and mostly everytime it trips the breaker (20amps) when the compressor turns on . i have allready left the unit with its own plug . any suggetions

07-19-2008, 05:35 PM	#2 (permalink)
Wozer TSF Enthusiast Join Date: Oct 2004 Posts: 1,010 OS: 2kpro/XP pro/MCE	Re: 12,000 btu window unit the fact that it is on its own plug means nothing....unless by some very small chance that plug is the only one connected to the breaker...when I had my house built 7 years ago I had one plug installed with a dedicated breaker for recording use...and I paid extra for that... the point is that its what is connected to the other plugs on the breaker that most likely matters....or perhaps the breaker is starting to go...I did a quick Google search for ac units with the specs you vaguely list and it appears as if they all fall within the ratings of a 20 amp breaker...but know this, the biggest draw that unit will give is just when it starts up, and the load it pulls may be towards the limits of the breaker just by itself...if you have another high amperage piece drawing electricity at the same time, then that is most likely the real cause...next time it throws a breaker figure out by deduction what other items are also on that circuit and deduce what item is also drawing a lot of amps.... __________________ Beware of the big 3 insurance companies in Texas! Read your policies carefully (maybe you'll need a lawyer) and enjoy the 6% increase in your rates you are about to receive from Allstate, Farmers & State Farm for most likely reduced coverage

08-05-2008, 08:20 PM	#3 (permalink)
mack1 TSF Articles Team Join Date: Nov 2007 Location: Texarkana, Texas Posts: 725 OS: xp sp2 My System	Re: 12,000 btu window unit Hi buenf, Wozer's advice is good. Wall plugs are usually connected with several on the same feed (breaker). Number 12 wire is used to wire 110 volt circuits and it is rated for 20 amperes. Do NOT entertain the idea of using a larger breaker. Breakers are rated for the wire, so that the wires won't overheat and cause a fire. A loose feed wire connection in the wall plug can cause the a heavy load to throw a breaker. Feel of the wall plug cover and see if it feels hot when it throws the breaker. If so, it is an indicator that the wire to the plug is loose. If you turn off the airconditioner and then immediately turn it back on, it will throw the breaker. It will still have pressure on the high side of the pump that has to be overcome at start, thus causing overcurrent. If you turn it off, wait about 30 seconds before turning it back on. For test purposes, you could try using another circuit (in another room) using a long extension cord. A 12 guage would be best, but you might get it to work with a 14 guage. (larger number is smaller wire) Borrow one from a neighbor or friend if you don't have one. The problem could also be the Start Capacitor in the unit. It is used to shift the phase of the current during start for heavy load. After start, a run capactor is switched in for best run phase shift characteristics. If you changed out the capacitor yourself, it would be $10 or less. Cost a lot more if you had someone to do it. If you find that the unit kicks out other breakers using the extension cord, it is probably a start problem in the unit. One ton units are't that expensive, so it might be time to replace it unless your like the idea of replacing the run capacitor. Hope this helps, Mack1 __________________ "If you like yourself others will like you also" me "Don't drink downstream from the herd" Will Rogers Submit New Articles Here