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Install & Replace

Converting Breakers

I have a double-pole 40A 240 breaker going to an outlet. I want to change the amperage as the equip I want to plug in is rated 20A 240V. The matching outlet for the equip is rated 240 and says Max 20A. Do I need to change the breaker for this, and if so, how?


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Posted 2013-02-16T21:32:15+0000  by citronut citronut

Hi citronut,


Quick answer to your breaker question is YES; if the equipment is rated for max. output of 20 amps  than you need to change the existing double pole 40 amp breaker to a double pole 20 amp breaker.


Another factor you may need to address is the size of the wire going in to the existing breaker? This is as equally important as the breaker alone.


Recommended size and type of the wire for the new replacement breaker is going to be indicated on the breaker body need to wire it within those limits.


As far as the breaker replacement in the panel goes, I’m not trying to discourage you, but this is something you should steer away if you're not “comfortable” with electricity.


Even with the main breaker flipped in the "OFF" position, wires feeding the breaker are still going to stay live and energized…

If you are really set on changing these on your own …than, post back with some pictures of the panel, replacement, breaker and the equipment label and I’ll try to help you with the replacement steps.


Right now I don’t feel like I have sufficient info to provide you with the safe and sensible instructions.


Thanks for posting here,



Posted 2013-02-18T15:27:18+0000  by George_HD_CHI

as far as the wire size goes you should be fine going from a 40A to a 20A breaker.  if you were going the other way i would say not a chance.  I do agree with SteelToes though, if you don't know what you are doing or are not comfortable; your best bet would be to either hire and electrician or have a friend that is comfortable with electricity help you out.

Posted 2013-02-18T15:34:12+0000  by joshcameron


Hey Josh,


I want to think he got # 10 in there, I see your point… but I’ve seen all kinds of funny stuff when it comes to electrical. Just last year, working on a remodel, I’ve came across 30 amps(2.5 ton AC) hooked up on # 12...

Or what about an old dryer outlet with #10,50amp converted to a kitchen outlet… not kidding.

I think I have a pic that I can share here...


I personally think we should see his panel, equipment and wire before we continue on...


BTW, what's your background?


You've got some good posts here... good job.



Posted 2013-02-18T16:10:43+0000  by George_HD_CHI

My background consists of 15 years in the Army Guard as a Vertical construction Supervisor including 2 tours in Iraq doing construction missions, 7 years doing HVAC install and 5 years as a maintenance manager for a large upscale resort in central minnesota.  i agree that we should definitely see his panel before any more advise is given.  Electricity is nothing to mess around with if your a novice.

Posted 2013-04-10T21:10:59+0000  by joshcameron
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