220V 15A breaker


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Old 05-11-18, 05:37 AM
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220V 15A breaker

I am planning an install for a mini split, the unit says 15A max and it’s 220v.

Went to Home Depot to check for parts, found my breaker type and the 15A breaker the guy pointed me to was a single pole but with two independent breaker switches.

Ive only ever done 20A and 30A 220v installs before and they were always 2 pole. Just wanted to check if this is correct. I always thought 220v needed to be on two poles.


Next question is emt vs type ac cable (Armored Cable). Wire run will exit the load center from the ceiling, then come down the wall 6ft and directly out to an exterior disconnect. Other wires are done with emt where exposed in the garage by the builder (2015) but not in the attic. Garage ceiling is finished with drywall.

I am planning to go with emt but I was courious about the AC. NEC seems to say AC can be used except in damp or wet conditions. But I’m not sure if it going directly into the disconnect box from the wall meets that condition or not.
 
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Old 05-11-18, 06:03 AM
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Sorry, 1 more thing to add. Builders ran Romex into EMT, I read that individual conductors are preferred, I was hoping I could use 10/3 incase I need to upgrade the circuit to 20A or 30A in the future. I assume that is acceptable and that 3/4" emt is recommended due to 1 90' degree bend that is required as it seems to be suggested when pulling romex through emt even if 1/2" would meet the fill requirements.
 
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Old 05-11-18, 07:30 AM
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You need a double pole 240V breaker. The breaker the HD guy showed you is two single pole breakers that fit in one space and can not be used for 240V. You can use #10 if you desire in case you need to increase the amp capacity. For 240V if using Romex (nm-b) you only need XX/2, not XX/3. The third wire is for neutral if also needing 120V. It's okay to exit the wall directly into the back of the disconnect box using AC or NM.
 
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Old 05-11-18, 07:33 AM
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Thank you for the response.

Yes now with more reading I am finding that is the wrong breaker and you can't get 240V from a single pole breaker, which is what I thought.

But then, that means I need to use a 20A 240V breaker. But the A/C unit says 15A max. Wouldn't that mean the AC unit can short circuit or something without tripping the breaker?
 
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Old 05-11-18, 08:08 AM
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Think I found what I needed, they didn't have them in store, but I found this online:
https://www.homedepot.com/p/Eaton-BR...15+%7Brest%7D+
 
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Old 05-11-18, 08:09 AM
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A 2P15A 240v breaker is nothing special. Try at an electrical supply house.

Since it appears you're running #10 wiring..... put in a 2P30 breaker and a fused disconnect with 15A fuses at the outside unit,.
 
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Old 05-11-18, 10:43 AM
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First - neither AC or MC are rated for physical protection. If on your inside garage walls then go with EMT.

Second - The inside of a disconnect is not considered a wet or damp location so it is OK to feed it with NM, MC, or AC. But the feed would have to come through the wall, not outside or in outside conduit.
 
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Old 05-17-18, 06:58 AM
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Went to Home Depot to check for parts, found my breaker type and the 15A breaker the guy pointed me to was a single pole but with two independent breaker switches.

Sadly this is becoming the norm at most box stores as they are more interested in filling a position with a warm body than someone actually qualified to give advice and labeling that warm body as a "Pro".
 
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Old 05-17-18, 09:28 AM
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Given the short run involved I would just run the #14 and skip the need for fuses in the disconnect . The breaker is most likely oversized at 15 amps.
 
 

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