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breaker amperage question

cbccadet2002

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Joined
May 7, 2013
Messages
18
I recently acquired a air compressor to replace my old champion 3/4hp. I get it home to discover that the dayton motor is rated for 230 volts. It's a 3 hp, 15.4 full working amp motor. I planned on resting it next to my dryer in my basement. Would it be acceptable to use a spare 3- wire dryer plug and use just use the dryer plug when i use the compressor? The outlet is a 30a- 125/250v Nema 10-30R. I'm not certain if the 30 amp outlet/ breaker combo is ideal or not for this application. I'm a machinist by trade, No electrical fires experienced in there yet :shocking: thanks for the insight
 
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pattenp

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Jun 4, 2008
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10,175
Location
Virginia - USA
Technically it will work. Is it to the letter of electrical code... no. I wouldn't lose any sleep over doing it. Be sure to use the L shaped plug prong for the ground from the compressor. The L shaped prong is actually a neutral.
 

RECox286

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Apr 11, 2012
Messages
1,399
Location
South Joisey (yeah, that is part of the USA)
Each hot leg of the circuit will show about 7 amp draw, so I would

use it as is, or replace the 30A bkr with a two pole 20A, and feed

the compressor with 12/2 romex. or replace the 30A receptacle with

a 20A receptacle and use a short cord with the correct male cord end.

If you follow my ranting.

Uncle Bob
 
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cbccadet2002

Member
Joined
May 7, 2013
Messages
18
ya i plan on getting a dedicated recip installed on the sub panel. But wanna check everything out on the compressor first. thanks.
 

wyliesdiesels

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Aug 14, 2012
Messages
20,004
Location
Modesto, CA
A 3HP motor is listed at 17a FLC. Wire is sized at 125% so if the wire feeding the outlet is #10 then you're fine but the outlet is not to code because its an old non-grounding dryer receptacle!

Each hot leg of the circuit will show about 7 amp draw, so I would

use it as is, or replace the 30A bkr with a two pole 20A, and feed

the compressor with 12/2 romex. or replace the 30A receptacle with

a 20A receptacle and use a short cord with the correct male cord end.

If you follow my ranting.

Uncle Bob

Huh? A 3HP motor is listed as having 17a FLC. Even at 15a nameplate rating the draw would be 15a seen on each leg because its a balanced load. The amp draw doesnt get split in half and divided among each leg!

12/2 Romex would not be correct either because of what i said above!

Also, u cant change the breaker to a 20a without also changing the receptacle to a 20a rated outlet! Bad advice!
 
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