Quick compressor wiring question

[G19Tony]

Hardwire or plug?

I'm starting to research compressors. Right now, I'm planning to have a 220 plug installed in my garage build. What I've seen on here, is that most guys are hardwiring the compressor to the box. Can you even use a plug for something like this?

Thanks.

 

[alfredeneuman]

If the motor is more than 3hp it needs to be hardwired.
If it is less or equal to 3hp then it may be cord connected.

 

[G19Tony]

If the motor is more than 3hp it needs to be hardwired.
If it is less or equal to 3hp then it may be cord connected.

Thanks. I'll talk to the electric contractor to make sure the box we put in can handle that.

 

[sands35]

If the motor is more than 3hp it needs to be hardwired.
If it is less or equal to 3hp then it may be cord connected.

Hardwired needs a disconnect means. It can be something like a AC disconnect, an appropriately rated double pole switch (they can look just like a light switch when the cover plate is on) or a "proper" motor disconnect throw switch.

 

[Charles (in GA)]

Hardwired needs a disconnect means. It can be something like a AC disconnect, an appropriately rated double pole switch (they can look just like a light switch when the cover plate is on) or a "proper" motor disconnect throw switch.

Good practice, but a disconnect is not needed UNLESS the equipment is more than 50 ft straight line distance with no walls or other interruptions in between and the disconnect/breaker must be in line of sight from the equipment.

Get more than 50 ft, or get out of the line of sight, even if only 10 ft, than a disconnect becomes mandatory.

If its plugged in, then that becomes the disconnect.

As already noted, there are no flat blade or turn lock type plugs and receptacles that are rated for more than 3 hp. Above that and you need pin and sleeve type connectors to do the job and they are quite expensive.

Charles

 

[G19Tony]

I haven't spoken to the contractor yet, but a proper shutoff box seems to be the way to go.

 

[C96]

Not just any type disconnect switch. The disconnect must be horsepower rated.

 

[wyliesdiesels]

OP wht is the model of the compressor u have?

 

[alfredeneuman]

OP wht is the model of the compressor u have?

G19Tony
"Hardwire or plug?
I'm starting to research compressors."

He hasn't selected the compressor yet

 

[G19Tony]

OP wht is the model of the compressor u have?

For the moment, I've decided to go with this. I won't be ordering until I get the floor down. The compressor is step... 50.


http://www.aircompressorsdirect.com/Quincy-2V41C60VC-Air-Compressor/p855.html

 

[wyliesdiesels]

Needs to be hardwired then!! Wire is sized at 125% of NEC table FLC(28a)- which means 35a wire. Either #8 NM or #10 THHN. Breaker can be max 250% of FLC or 70a. U may be able to use as low as 35a breaker but may have to go higher if u get nuisance trips!

 

[G19Tony]

Needs to be hardwired then!! Wire is sized at 125% of NEC table FLC(28a)- which means 35a wire. Either #8 NM or #10 THHN. Breaker can be max 250% of FLC or 70a. U may be able to use as low as 35a breaker but may have to go higher if u get nuisance trips!

The specs call for a recommended breaker of 50A. The electrician says we can use a 50A outlet, but I'm not comfortable with that, so I'm going to have them put in a shutoff panel and hardwire it to the box.

 

[wyliesdiesels]

The specs call for a recommended breaker of 50A. The electrician says we can use a 50A outlet, but I'm not comfortable with that, so I'm going to have them put in a shutoff panel and hardwire it to the box.

That would violate the UL listing of the device because its only rated upto 3hp!

 

[LS6 Tommy]

If the motor is more than 3hp it needs to be hardwired.
If it is less or equal to 3hp then it may be cord connected.

Not arguing code, but my Craftsman 5.5 HP 30 gallon has a NEMA 5-15 plug from the manufacturer & I see the same on other brands of portable compressors rated over 3HP everywhere. Is there a reason why this is OK?

Tommy

 

[wyliesdiesels]

Not arguing code, but my Craftsman 5.5 HP 30 gallon has a NEMA 5-15 plug from the manufacturer & I see the same on other brands of portable compressors rated over 3HP everywhere. Is there a reason why this is OK?

Tommy

The compressor probably does not have a true 5.5hp motor. Wha is the FLA rating on the nameplate?