Air Compressor

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mbrooke

mbrooke

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Technician
Do motor sizing rules apply to air compressors? I want to say they do, but don't remember off the top of my head.
 
I'd say generally, yes.
Some of the smaller ones actually have "spl" motors where nameplate data must be used.
It's still Art 430, but an exception.
 
IMO, I believe the smaller cord & plug type compressors are actually listed (UL) as "appliances" (QDFT) and would be governed by Art 422 and 210 Part II as far as plugs and receptacles.
Other than those, if you cord and plug connected a larger, non-appliance compressor, the cord and plug would need to be HP rated.
 
augie47 said:
IMO, I believe the smaller cord & plug type compressors are actually listed (UL) as "appliances" (QDFT) and would be governed by Art 422 and 210 Part II as far as plugs and receptacles.
Other than those, if you cord and plug connected a larger, non-appliance compressor, the cord and plug would need to be HP rated.
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o_O

So here is this:

www.homedepot.com

Husky 60 Gal. Stationary Electric Air Compressor C602H - The Home Depot

Use this portable Husky Stationary Electric Air Compressor for inflating car and bike tires. Equipped with pressure gauge.
www.homedepot.com

HP rated?

I hate to ask on what is pretty much DIY/apprentice level stuff but I think this is the biggest code stumper I've encountered... I'm clueless.

And disclaimer: this is not going in my house.
 
From the accompanying data it appears to be a 3.7 HP motor at about 14A on 240.
An accessory shows as a 20amp 240v cord & plug.
 
This is not a cord & plug unit. Specifically states that it does not come with a cord.
According to the instructions, the motor nameplate is 17.2 A , 230 V and requires a 30A breaker. The motor has thermal overloads.

I would wire it up with flexible conduit due to vibration.

ETA: I suppose it could be wired with cord & plug if frequent relocation is a requirement. It would need to be HP rated, I believe.
 
mikeames said:
125% of the 17.2 = 21.5Amps
and
Because I am following the instructions where relevant and where they are silent I go to NEC. So the instructions don't specify OCPD size so I used the 250%.
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The instructions specify a 30A breaker:

“Please consult your local codes and a certified electrician before wiring this compressor for power. (This unit requires a 30 amp double pole breaker for proper installation)”
 
mikeames said:
125% of the 17.2 = 21.5Amps
and
Because I am following the instructions where relevant and where they are silent I go to NEC. So the instructions don't specify OCPD size so I used the 250%.
Click to expand...

If the motor is continuous duty... can the argument be made for 115%?
 
retirede said:
You are correct - no OCPD rating specified there. I was quoting the website, not the official instructions. Sorry if it caused confusion.
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Don't ya love how the instructions say a min circuit of 20A.
The web site tells you 30 amp circuit required.
The instructions say consult a qualified electrician and you could use a 40A circuit on 10 awg.
 
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