Robert Hall
Well-known member
Good catch. The cord is 6 guage.
Good catch. The cord is 6 guage.
What would the correct way to replace the Cord with what ? ThanksStill not right as Norcal said above!
What would the correct way to replace the Cord with what ? Thanks
Compressor in shed with 10-3 on a 50 amp 220 single phase.
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Cord is illegal regardless of wire gauge. You must hard wire stationary equipment.
Tommy
I want to comment on this. I really doubt the guy holds a licence, most in maintenance do not andf a good share of them learned hand to mouth. They are notorious for this type of thing. They usually work with 3 ph and even higher voltages and a good share of them havnt spent a day in school over this. They simply size wire the way they see it at work. Grounding is another issue too. Often it isn't correct.I wanted to bump this back up to the top and just say......My electrician wired my compressor wrong!!!! It's wires with #12 wire, and I had no reason to really doubt him as he is certified and wires machinery up at work all of the time.
BUT.....after listening to the replies on here, I dug around in every place I could think of to find the book on my compressor. BTW.....Menards pamphlet holder in the lid of their toolboxes, can hide a manual.And sure enough it calls for No.10 wire. I sort of forgot about it until I was cleaning the garage the other day. So I will be swapping that wire out. And I want to thank everyone for pointing it out. Next time that I have something similar wired that I'm not familiar with, I'll ask here first before I get a local electricians idea on things
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You're misinformed.
Cord is allowed to be used in the "prevention of the transmission of noise and vibration". Taken directly from 400.7(A) of the NEC.
Sized properly and with proper strain reliefs for support there is no issue.
Thanks for pointing out my loss of memory. Normally that is accomplished with flex and THHN so it just "looks wrong". His install still violates code as there are no strain reliefs.
Tommy
My compressor has a label 5 Hp, 20 Gallon, came from the store with a cord and molded plug, and works just fine, plugged into a 15 amp receptacle fed with 12 gauge through a 20 amp breaker.
As long as it works, I have no intentions of fixing it
My compressor has a label 5 Hp, 20 Gallon, came from the store with a cord and molded plug, and works just fine, plugged into a 15 amp receptacle fed with 12 gauge through a 20 amp breaker.
As long as it works, I have no intentions of fixing it
You've been on this forum long enough that you should know there is a difference between wiring for appliances and air compressors that come with a cord and molded plug and those that do not. Also, if you think the manufacturer is running a true 5HP motor through a 15 amp cord end, I think you're mistaken.
We are talking about wiring for a REAL 5HP compressor with no factory cord and molded plug. Not the economy grade **** c ompressors they sell to gullible people with overstated HP claims.
But well stated before my change.Fixed it for ya.But well stated before my change.
Edit in itallic.

I used #10 in conduit. Total length is 6FT and it's hooked to a 30A breaker.
My compressor is a 5HP Quincy. Everything seems to work great.
Here is how I wired mine. Everything was piped in EMT conduit and this installation passed inspection last week. Hope this helps!
My 5HP Matco compressor with IR 2430 two stage pump.
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Motor Tag: 5.0hp, 21.5amp, 230v
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Subpanel
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2 Pole 30A Breaker feeding compressor
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Four (4) 10awg THHN stranded wires running from breaker to receptacle. Wiring includes two hots (red and black), one neutral (white), and one ground (green)
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Receptical and plug for compressor: NEMA 14-30R&P 125v-250v
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Well I bet that plug and outlet isnt rated for 5HP.
Shouldve been hardwired.
And thats the wrong plug for 240v equipment. A 14-30p and r is for 120v/240v equipment such as a dryer. Shouldve used a 6-30p and r IF its rated for 5HP.
Glad to see the inspector did his job!![]()
Is that pressure switch rated for 5HP?

No comment on the inspector. His tag = "approved" setup.
The panel and circuit to the outlet is all the inspector approved. The inspector has no control over what you plug into that circuit. So the circuit in itself is okay. The plug on the compressor is just not proper as a disconnecting device because it's under rated for the motor HP.
Is that pressure switch rated for 5HP?
Where can I find plug/outlet ratings for motor HP?
Pin and Sleeve plugs and outlets are higher HP rated but they are expensive. That's why hardwiring is suggested.
Here's why the HP rating matters.......
http://forums.mikeholt.com/showthread.php?t=164752
also see...
http://www.hubbell-wiring.com/press/pdfs/H5247.pdf
So i am looking to buy a Quincy QT-5.
How should it be wired?
I have a 220 plug near the spot i was going to set the compressor that has a 60 amp breaker.
Is it not possible to use a plug given it the sized appropriately? If so, which one?
There are pin and sleeve plugs rated for 5HP but they are not cheap. You need to use a proper HP rated plug or hardwire the compressor to be NEC compliant. I assume you read the posts previous to yours to ask this question.
Would be much simpler for me to just use the correct plug as to have an electrician hard wire it.
So i am looking to buy a Quincy QT-5.
How should it be wired?
I have a 220 plug near the spot i was going to set the compressor that has a 60 amp breaker.
Is it not possible to use a plug given it the sized appropriately? If so, which one?
I did read all the post.
Would be much simpler for me to just use the correct plug as to have an electrician hard wire it.
http://www.elecdirect.com/pin-sleeve-devices/60-amp-pin-and-sleeve-devices
Those things are pricey. Never seen one like that.
You cannot direct wire equipment w/ cord as it is not permitted to be a substitute for permanent wiring, either put a plug on it, or use sealtite,(liquid tight flexible metal or non metallic conduit), or flexible metal conduit.
You're misinformed.
Cord is allowed to be used in the "prevention of the transmission of noise and vibration". Taken directly from 400.7(A) of the NEC.
Sized properly and with proper strain reliefs for support there is no issue.
It seems that u and Norcal are in disagreement regarding the usage of cordage for equipment wiring.