Air Compressor power supply

[bigtiller]

I just bought a Quincy 5 hp compressor. It has a 5 hp 230 volt motor that wants 24 amps. I have a 50 amp outlet close to where I want the compressor, that I never use. I think need to shrink it down a little. Is a 25 amp breaker enough? Are 30 amps too much?

http://www.northerntool.com/shop/tools/product_200350475_200350475

 

[KennyG]

Not sure what you are worried about. The breaker should be sized for the wiring, not the attached load. If you have 50 amp wiring, leave it at 50 amps. If you have a fault in the compressor, it will trip the breaker whether it's 30 or 50 amps.

 

[Mysfyt]

I'm sure a real electrician will be along soon and confirm this, but I believe the rule is a breaker should be 125% of the load. That puts you at 30 amps.

 

[Bird]

I'm sure a real electrician will be along soon and confirm this, but I believe the rule is a breaker should be 125% of the load. That puts you at 30 amps.

Yes, but aren't you talking about "minimum" of 30 amps? I'd do the same as KennyG said.

 

[dickfoster]

What the others have said, breakers and fuses are sized to protect the wiring not the load. The breaker is there to keep your building from burning down and nothing more. The minimum sized wiring is determined by the anticipated circuit load. The load should have it's own protection built in if needed and most do.

 

[Buggs67]

What they all said. The only problem might be the plug matching the outlet. I've seen some plugs (like RV 30A) that have different plug configuration. If so change the plug or change the outlet.

 

[bigtiller]

The compressor is brand new and does not have a plug.

So, I can get a plug to fit in the old clothes dryer 50 amp outlet and run with that? Sounds simple enough.

 

[LittleBill21]

The compressor is brand new and does not have a plug.

So, I can get a plug to fit in the old clothes dryer 50 amp outlet and run with that? Sounds simple enough.

clothes dryer is 30 amp not 50 amp, welder/ovens are 50 amp, are you sure you know what your working with?

 

[bigtiller]

clothes dryer is 30 amp not 50 amp, welder/ovens are 50 amp, are you sure you know what your working with?

I thought the electrician that put it in 18 years ago called a 50 amp dryer outlet. Or maybe not. It was installed to run my welder. Any way, it is powered by a 60 amp breaker and I ran my Forny welder on it for a year.

 

[Sawyer Rob]

Jut buy a matching plug, and quit worrying... If it was wired for a 220v welder, you are in business!

SR

 

[joefromga]

Breakers are sized for permanent loads like AC, water heater, oven, etc. Not plug-in items.

 

[boomer1025]

Jut buy a matching plug, and quit worrying... If it was wired for a 220v welder, you are in business!

SR

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:thumbsup:

 

[bigtiller]

To anybody that is still listening, thanks for the help. How about another question.

What is a good, economical dampener for under the feet of the 60 gallon tank when i bolt it to the concrete floor? Or should I just leave it bolted to the shipping pallet?

 

[aczlan]

I have seen them left on the pallet with no ill effect. They often come with rubber feet on the bottom to dampen vibrations.

Aaron Z

 

[Bird]

When I had a 60 gallon compressor, I left it bolted to the shipping pallet. It never moved and I could more easily reach underneath to open the condensation drain.

 

[Sawyer Rob]

What is a good, economical dampener for under the feet of the 60 gallon tank when i bolt it to the concrete floor?

A small square of old semi mud flap (or equivalent) under each foot with the bolt going right through it.

SR

 

[CalG]

cut 4 inch squares out of an old snow tire tread.

A die grinder with a cut wheel is the ticket, but stinky! A sawzall will gnaw through steel cords also.

 

[bigtiller]

Part of the deal was "free shipping" to my door. All i have to do is take it off the truck with my pallet forks. My first thought was to leave it on the pallet to see if i like it in the spot i have chosen for it,but. I'm not sure i want to give it that much floor space.

As i was thinking of the tire and mudflap ideas I remembered there is an automotive junk yard just a mile away. I will call him and see what we can find in his 10 acre shopping mall. I haven't walked down the isles for a lot of years.

 

[the old grind]

If the pallet is well built (ya never know) just attach wheels under that while it's on the forks. (.. and be sure it's still strapped from tipping off them if/when you do. ... disclaimer)

My tank drain is piped out to the edge of the pallet with a shut-off, and there's ample room to slide a can or pan below that when I do the chore. (2-stage compressor, bandsaw, drill press, shop crane, and several work tables/benches have had wheels from day one. Shop press and table saw will sport them soon, as well as a planned dolly for the grapple.)

Anyway, IMO the ultimate electrical protection for the OP's compressor would be to install a separate, lockable, fused disconnect. Fuses rated for 'motor' use (time delay) might save the motor from itself if/when things go awry. (motor stall, etc) This type fuse (usually cartridge, btw) will allow motor start surges (brief, but ~ x7 FLA) but fully protect the motor if power wire/plug is sized to the load vs the main's '50/60?' amps.

A plug for that specific amperage would be best on/in that 'box'. Other guys on the main circuit still draw as they're wired/fused. My 230v mill & lathe are wired this way as std shop practice. (tho' w/o plugs) tog

 

[buickanddeere]

I just bought a Quincy 5 hp compressor. It has a 5 hp 230 volt motor that wants 24 amps. I have a 50 amp outlet close to where I want the compressor, that I never use. I think need to shrink it down a little. Is a 25 amp breaker enough? Are 30 amps too much?

http://www.northerntool.com/shop/tools/product_200350475_200350475

The Breaker is only there for Short Circuit Protection. The starter on the Compressor supplies the Over Load Protection which is a completely different type of protection but most folks can't tell the difference .
According to the Code book the 24 running amp motor , A minimum of a 30 amp conductor, max fast acting fuse 80 amp, max 60 amp time delay fuse and maximum of a 60 amp breaker.
pretty soon somebody will come along and swear that a 80 amp fuse or 60 amp breaker can not be used with a 30 amp conductor.