#6 stranded wire

[mitusa]

I've decided to wire up my 80 gallon 220 volt IR air compressor. It's been a while; I built my shop in 2005. I ran a wire for any 220 over to the edge of my shop and put it in a junction box. It is I think three #6 wires (red, black, white) with a bare copper wire.

The run to my compressor is about twenty feet. The motor on the compressor is a 40 amp. I need to know the proper way to join the wires together in the junction box. I've already twisted the two coppers together and grounded them to the junction box. Can I twist the stranded # 6s together or do I buy lugs and bolt them together? Should I use a 40 amp breaker or 50? And I'm hard wiring it direct to the compressor.

Thanks for any suggestions and answers!

 

[LXCam]

They make wire nuts suitable for that size. But a split bolt, rubber tape covered in 3M 33 is a much better solution. That 50 amp breaker may be fine, it all depends on what pressure you restart at and how long that inrush current is sustained and the type of breaker you use. More then likely, you'll be fine.

 

[walrus]

I've decided to wire up my 80 gallon 220 volt IR air compressor. It's been a while; I built my shop in 2005. I ran a wire for any 220 over to the edge of my shop and put it in a junction box. It is I think three #6 wires (red, black, white) with a bare copper wire.

The run to my compressor is about twenty feet. The motor on the compressor is a 40 amp. I need to know the proper way to join the wires together in the junction box. I've already twisted the two coppers together and grounded them to the junction box. Can I twist the stranded # 6s together or do I buy lugs and bolt them together? Should I use a 40 amp breaker or 50? And I'm hard wiring it direct to the compressor.

Thanks for any suggestions and answers!

No motor controller ?

 

[mitusa]

No motor controller ?

The compressor has an on/off switch in a box with the wiring lugs...Is this what you are referring to????

 

[walrus]

The compressor has an on/off switch in a box with the wiring lugs...Is this what you are referring to????

Might be, is there a relay in it? How many horse power is the motor?

Here is an example of a motor controller, not the one for you just a random example

https://www.zoro.com/franklin-contr...urN-cVBU3LWdRhSnDDabMaAg4G8P8HAQ&gclsrc=aw.ds

 

[mitusa]

Might be, is there a relay in it?

As you might have guessed, electrical wiring is not my strong suit.

The box with the wiring and on/off switch is located on the pressure regulator.

The factory wires then go from there to the motor. The motor does have a reset button. And I have run the compressor before by running a smaller 12/2 wire from my welding plug to the said box and it ran fine. I'm just trying to wire it so I can turn on the switch and it will run.

Thanks much for the help! It's a 5HP. Max amp is 40 amps. Nothing like your picture on my compressor.

 

[zmaxmotorsports]

They make wire nuts suitable for that size. But a split bolt, rubber tape covered in 3M 33 is a much better solution. That 50 amp breaker may be fine, it all depends on what pressure you restart at and how long that inrush current is sustained and the type of breaker you use. More then likely, you'll be fine.

 

[pattenp]

Since you've wired it with #6 just use a 50A breaker. You said the motor has a reset button so the motor has its own overload protection. The only thing is you don't need the white wire so cap it off. Compressor doesn't use a neutral.

 

[md21722]

It does not make any sense that the motor is 5HP and also 40A. 5HP motors have nameplate around 19-23A. It sounds more like you might have a 7.5HP (33A common nameplate) or 10 HP (40A common nameplate) ??? For code, HP determines the wire size & breakers, but with #6 THHN you are good on wire size up to 10HP. Double pole breakers are usually the same cost up to 60A. After that there is a price jump. You can technically run a 5HP off a 70A breaker, but in practice 30A usually works fine. If you do have a 10HP, you're better off with a 60A breaker. An expensive alternative to large wire nuts and split bolts are Polaris connectors. As pattenp said, the white is not used and should be capped off. Red and black go to the pressure switch. It does not matter what line in lead gets red and black. They are both hots and interchangeable.

 

[mburrus]

you can use blue wire nuts for 2#6... i prefer the ideal wing nut brand.

or use polaris gutter taps (or similar) for a set screw connection. i wouldnt mess around with splitbolts and electrical tape... its always messy if you need to get back in to it...

 

[wyliesdiesels]

Does the motor have a nameplate?

Post a pic of it here!

What about the pressure switch?

 

[mitusa]

It does not make any sense that the motor is 5HP and also 40A. 5HP motors have nameplate around 19-23A. It sounds more like you might have a 7.5HP (33A common nameplate) or 10 HP (40A common nameplate) ??? For code, HP determines the wire size & breakers, but with #6 THHN you are good on wire size up to 10HP. Double pole breakers are usually the same cost up to 60A. After that there is a price jump. You can technically run a 5HP off a 70A breaker, but in practice 30A usually works fine. If you do have a 10HP, you're better off with a 60A breaker. An expensive alternative to large wire nuts and split bolts are Polaris connectors. As pattenp said, the white is not used and should be capped off. Red and black go to the pressure switch. It does not matter what line in lead gets red and black. They are both hots and interchangeable.

Sorry, my mistake. I looked again; it is a five horsepower, but it's not a 40 amp. It says 40 AMB and 23 FLA. AMB is ambient temperature. And FLA is full load amps. From what I can tell on google. Sorry again for the wrong info; my eyesight ain't what it used to be.

Thanks again for the info. This board is very useful.

 

[wyliesdiesels]

Sorry, my mistake. I looked again; it is a five horsepower, but it's not a 40 amp. It says 40 AMB and 23 FLA. AMB is ambient temperature. And FLA is full load amps. From what I can tell on google. Sorry again for the wrong info; my eyesight ain't what it used to be.

Thanks again for the info. This board is very useful.

Ok so heres the low down:

Motor circuit wiring is sized @ 125% of NEC table FLC. For 5HP(28a) this means #10 THWN or #8/2 NM-b.

Breaker can be max 250% of NEC table FLC.

Motor needs to be hardwired unless a plug and receptacle rated for at least 5HP is used. Standard NEMA plugs and receptacles are rated to about 3.5HP.

Since u dont have a starter, is the pressure switch rated for 5HP?

Can u take some pics and post them here.