need some help wiring a 220v air compressor to a dryer plug

DemonRR · May 19, 2012

I need some help from you fine folks. please forgive my lack of electrical knowledge and terminology. I bought a 60gal, 5hp, single phase, 220v air compressor to do some side jobs at home (i am a bodyman). i have a very limited power supply in my garage (live in a condo), so what i have is for lighting and my radio. i have my dryer about 15' away in a closet in the house, from where my air compressor is in the garage. i would like to make a wire/cord set-up that i can just plug into the existing dryer outlet (unplugging the dryer when using the conpressor of course) when im working in the garage. after reading thru many threads on here, i think its best to ask the people who know what their doing, rather than just "hope" i did it the right way an NOT burn down my condo as well as the condos attatched to mine. the dryer has (2) 30amp circuit breakers connected.

heres a pic of the power box on the air compressor, and a pic of the dryer plug.

thanks for your help everyone.

and if i can repay you for any bodywork questions, please feel free to ask away. i be more than happy to help out.

thanks
dave

the power box on the compressor takes a 3 wire connection in (red/black/green) and 2 wire out to the compressor motor (black/white)

pattenp · May 19, 2012

That is a NEMA 10-30 plug, it is classified as a 30 amp 125/250 V non-grounding (hot-hot-neutral). Technically if the dryer outlet is wired back to a main service panel the neutral is bonded with the ground so in effect the neutral is also used as a ground. So the L shaped spade would be used for the green/ground and the 2 flat spades are the two hot wires (red/black).

You need to verify that the compressor needs less than 30A, actually no more than 24A.

DemonRR · May 19, 2012

my bad, i forgot to put the compressor rating. its 15 amps. also, what kind/type of wire. solid, strand, rated to 600v?

thanks for the help!!

pattenp · May 19, 2012

If you are going to wire a cord and 10-30 plug on the compressor you will need to use 10/3 SO cord, that's two hots plus a ground.. The 10/3 SO cord may be a little beefy to hook up to the pressure switch. Actually you only need a 20A circuit for the compressor which would only require #12 wire, but you should not use a 30A plug on 20A wire and plug it into a 30A circuit.

Gregishome · May 19, 2012

DemonRR said:
my bad, i forgot to put the compressor rating. its 15 amps. also, what kind/type of wire. solid, strand, rated to 600v?

thanks for the help!!

Confused now..... Above you state the compressor is a single phase 220V/5 Hp. /60 gallon tank. Might want to recheck that nameplate amperage rating on the motor, 15 amps sound to low. Should be in the 22-28 amp range ?.

pattenp · May 19, 2012

I think that 5hp is the usual over stated motor HP for sales hype..

DemonRR · May 19, 2012

waiting for the pic go from phone to computrer then upload it here. it says 5hp, 60hz, 15 amps, 230 volts.

Gregishome · May 19, 2012

Good point Patten,

I remember my 60 gallon 220 V 5HP V-twin iron cylinder vertical SpeedAire air compressor was nameplated at 22 amps and my Fluke amprobe read 22 amps on the line conductors whenever it was running to load up. .

Yes, DRR. you have the right ratings as indicated by the nameplate. My apologies for side tracking..............

pattenp · May 19, 2012

I should mention that technically a horse power rated plug and receptacle should be used that has a rating no less than the motor hp rating to serve as a disconnecting means.

DemonRR · May 20, 2012

Gregishome said:
Good point Patten,

I remember my 60 gallon 220 V 5HP V-twin iron cylinder vertical SpeedAire air compressor was nameplated at 22 amps and my Fluke amprobe read 22 amps on the line conductors whenever it was running to load up. .

Yes, DRR. you have the right ratings as indicated by the nameplate. My apologies for side tracking..............

no worries at all. better safe than sorry, especially when it comes to electrical wiring.

pattenp said:
I should mention that technically a horse power rated plug and receptacle should be used that has a rating no less than the motor hp rating to serve as a disconnecting means.

the dryer plates says its 30 amps. i have a small stackable washer/dryer combo that fits nicely in a closet. so i imagine the plug is safe to use wiht my 15amp air compressor, no?

thanks again for all your help everyone. ive had this compressor sitting in my garage for 6 months now collectin dust. ive had so many mixed answers in the past, and were all wrong. i cant wait to start doing some side work and projects. mainly prepping and painting my new race bodywork for my motorcycle.

PT Doc · May 20, 2012

I think the goofy situations here is that it says 5 hp and 15 amps. Those numbers don't jive. And 15 amps is a obviously a 120v amperage in any house. The advise is correct. I'll add that you could you SJO cord that is rated for 300v. I like the SO cord for added durability but it's really not needed.

I will say this though. That receptacle is likely not rated for your 3.25 hp motor but that is a whole other discussion. Leviton makes 50 a receptacles and plugs but these are not rated for 5hp motors even though you are correct on the voltage and amps. If memory serves me, a 30a plug will be rated for 2hp.

DemonRR · May 20, 2012

this is the cord i ordered. https://wesbellwireandcable.com/SOOW/SOOW10-3.html d will source the dryer plug from home depot or lowses. i just want to make sure i dont start a fire from pulling power this way. imy dryer/washer combo is pulling 30a (rated), and its pulling from the circuit breaker dual 30a breakers, then can i assume ill be fune wiht my 5hp 15a compressor motor? the tag on the motor itself says 15a also @ 3450 rpm and is thermally protected.
bought this from my painter co-worker. he used this at his house pulling 220v. e had this on a 4 prong plug, i opened it up to inspect it, and only 3 wires were wired/connected.

jbberns · May 20, 2012

PT Doc said:
I think the goofy situations here is that it says 5 hp and 15 amps. Those numbers don't jive. And 15 amps is a obviously a 120v amperage in any house. The advise is correct. I'll add that you could you SJO cord that is rated for 300v. I like the SO cord for added durability but it's really not needed.

I will say this though. That receptacle is likely not rated for your 3.25 hp motor but that is a whole other discussion. Leviton makes 50 a receptacles and plugs but these are not rated for 5hp motors even though you are correct on the voltage and amps. If memory serves me, a 30a plug will be rated for 2hp.

1 hp = 746 watts
746x5=3730 watts
3730/240=15.54 amps.
x multiplier for overload protection

pattenp · May 20, 2012

Being that the compressor only uses 15A, I don't see a problem.

DemonRR · May 20, 2012

i speak fluent autobody repair, not electricity. lol am i safe with what i ordered and the way i want to wire it up? you guy are awesome. thanks so much. i hve a ton of side work to do and no air compressor to get the work done.

if anyone ever has any autobody, paint or the like questions, please feel free to ask away.

jbberns · May 20, 2012

it'll work fine

DemonRR · May 25, 2012

pattenp said:
That is a NEMA 10-30 plug, it is classified as a 30 amp 125/250 V non-grounding (hot-hot-neutral). Technically if the dryer outlet is wired back to a main service panel the neutral is bonded with the ground so in effect the neutral is also used as a ground. So the L shaped spade would be used for the green/ground and the 2 flat spades are the two hot wires (red/black).

You need to verify that the compressor needs less than 30A, actually no more than 24A.

igot the cable in the mail today and grabbed the male dryer plug i needed. on the dryer plug directions, it lists the white wire being the neutral (backwards L shaped" blade, and lists the black and red wires as the side wires (hot/hot).

so this would be the correct way to wire this, no? use the green wire as the ground, and the white/black wires for hots. so green from the cable is the L shaped blade, and the white and black are the hots (side blades)?

thanks once again everyone

pattenp · May 25, 2012

Correct.

DemonRR said:
igot the cable in the mail today and grabbed the male dryer plug i needed. on the dryer plug directions, it lists the white wire being the neutral (backwards L shaped" blade, and lists the black and red wires as the side wires (hot/hot).

so this would be the correct way to wire this, no? use the green wire as the ground, and the white/black wires for hots. so green from the cable is the L shaped blade, and the white and black are the hots (side blades)?

thanks once again everyone

DemonRR · May 25, 2012

thanks again. just makin sure.

ford33 · May 26, 2012

I hope you have nice neighbors. Townhome and condo associations are not very accepting of people operating businesses with loud machines in the community. I have lived in these communities and know that loud music can draw complaints. When you are operating an air compressor and sanding dust is flying out of the garage, you will get the attention of the association. Good luck.

DemonRR · May 26, 2012

i have great neighbors, as i am a great neighbor. im actually moving the compressor in the basement, and drilling a hole in the wall to run my air line thru it. parking compressor right next to my noisy new(er) neighbors basement wall. damn loud kids always banging on the walls and such all hrs of the day. and i dont "operate a business" i just do side work.

but thank for your concern.

Quickster · May 29, 2012

So you got everything up and running? I actually had the same question. Did a google search and landed here.

I plan on purchasing this compressor if I can't come across a nice deal on craigslist for a different/better ratings one.

http://www.lowes.com/pd_54284-1126-...__?Ns=p_product_qty_sales_dollar|1&facetInfo=

Air Compressor Voltage 230
Amps (Amps) 15.0
Horsepower (HP) 3.7

Air Delivery SCFM @ 40PSI 13.4
Air Delivery SCFM @ 90PSI 11.5

Should do fine and hold me over until I can afford this, and get serious with some body work. http://www.northerntool.com/shop/tools/product_200350475_200350475

mikemeg · Dec 31, 2014

DemonRR said:
i speak fluent autobody repair, not electricity. lol am i safe with what i ordered and the way i want to wire it up? you guy are awesome. thanks so much. i hve a ton of side work to do and no air compressor to get the work done.

if anyone ever has any autobody, paint or the like questions, please feel free to ask away.

How do I get paint rub/ minor scratches out of a silver truck ? they are not deep enough to feel the scratches...thanks.. :thumbup:

LS6 Tommy · Jan 1, 2015

Does the motor info plate list the HP, or does it just say "SPL"? If it says "SPL", its not a true 5 HP motor. I bet it's an "SPL". Probaly closer to 3-3.5 HP with 230VAC at 15A...

Tommy

SweetD · Jan 1, 2015

Not for nothing, but this thread is over two and a half years old...

pv74 · Jan 1, 2015

I've done it with a 3HP table saw when I lived in a condo....LOL. It worked fine, but soon landed me in trouble with my wife. I used 10 gauge service cord from Lowes to build a special extension cord. I've also run a stick welder that way.

Not the best way or a permanent way to do things, but it will work in a pinch.

LS6 Tommy · Jan 1, 2015

SweetD said:
Not for nothing, but this thread is over two and a half years old...

Duh. I didn't even notice...

Tommy

need some help wiring a 220v air compressor to a dryer plug

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