Less than ideal compressor wiring

[keith5064]

Needed some fast air so I temporarily set up my Coleman powermate 60 gallon compressor. Used 10 gauge romex on a double 20 breaker. As you see in the picture I ran the romex down the wall and into the pressure switch on the compressor. While it does work I know its not correct, plus its looks like poo. The compressor sits about 10-15ft away from the electrical panel. My thought was to get about 5 ft of a S.O. type cord cut the romex and install a junction box, the S.O. cord would come out of the junction in to the compressor. I would use a seal tight type conduit, but there is no good way to connect it into the pressure switch(I.e. no knockouts) its just a clamp which kind of makes it a pita. Is this a reasonable way to connect this?

Sent from my XT1080 using Tapatalk

 

[keith5064]

Needed some fast air so I temporarily set up my Coleman powermate 60 gallon compressor. Used 10 gauge romex on a double 20 breaker. As you see in the picture I ran the romex down the wall and into the pressure switch on the compressor. While it does work I know its not correct, plus its looks like poo. The compressor sits about 10-15ft away from the electrical panel. My thought was to get about 5 ft of a S.O. type cord cut the romex and install a junction box, the S.O. cord would come out of the junction in to the compressor. I would use a seal tight type conduit, but there is no good way to connect it into the pressure switch(I.e. no knockouts) its just a clamp which kind of makes it a pita. Is this a reasonable way to connect this?

Sent from my XT1080 using Tapatalk

Sent from my XT1080 using Tapatalk

 

[Mustang51js]

You can do it that way,or do a 20 amp twist lock plug and cord end,this way you can unplug it if you need it moved,and just use the rubber cord to it,no reason to use seal tight over it

 

[wyliesdiesels]

Cordage is not to be used for a permanent install.

What is the HP rating of the compressor?

 

[xxaler]

155psi 60-80gallong is 3.7HP 5HP peak, 12-14a draw.

 

[keith5064]

You can do it that way,or do a 20 amp twist lock plug and cord end,this way you can unplug it if you need it moved,and just use the rubber cord to it,no reason to use seal tight over it

I thought I read somewhere a plug in end was not allowed?

Sent from my XT1080 using Tapatalk

 

[keith5064]

155psi 60-80gallong is 3.7HP 5HP peak, 12-14a draw.

The motor reads 15a

Sent from my XT1080 using Tapatalk

 

[xxaler]

Don't see why it wouldn't be. Welders don't need to be hardwired.

I have mine on a 50' 12/2 cord with a plug on the end and it's fine on it's 15a breaker.

 

[keith5064]

Don't see why it wouldn't be. Welders don't need to be hardwired.

I have mine on a 50' 12/2 cord with a plug on the end and it's fine on it's 15a breaker.

Well heck problem solved, twist lock it is..problem solved! Thanks guys!

Sent from my XT1080 using Tapatalk

 

[wyliesdiesels]

I thought I read somewhere a plug in end was not allowed?

Sent from my XT1080 using Tapatalk

For motor circuits it depends on the HP rating of the plug. Standard NEMA plugs arent rated for more than about 3 sometimes 3.5HP.

So if the compressor is rated say 5HP, good luck finding a plug that will work unless u shell out serious bucks for pin and sleeve plugs...

 

[keith5064]

For motor circuits it depends on the HP rating of the plug. Standard NEMA plugs arent rated for more than about 3 sometimes 3.5HP.

So if the compressor is rated say 5HP, good luck finding a plug that will work unless u shell out serious bucks for pin and sleeve plugs...

Which installation method would you use in this particular situation?

Sent from my XT1080 using Tapatalk

 

[engineer031]

15 amps so it is a 3 HP motor you can use a plug on it fine I have that on my small compressor I run 12/2 with a 20 amp breaker and have a 20 amp twist lock outlet and plug it in

 

[alfredeneuman]

15 amps so it is a 3 HP motor you can use a plug on it fine I have that on my small compressor I run 12/2 with a 20 amp breaker and have a 20 amp twist lock outlet and plug it in

That's not the way it works in the US.

A chart in the NEC is used that determines the load of various size motors.

 

[engineer031]

That's not the way it works in the US.

A chart in the NEC is used that determines the load of various size motors.

I dont see why it would not be the same in the US the motor is only rated for 15 amps so what would you need to use in the US then ?

 

[alfredeneuman]

I dont see why it would not be the same in the US the motor is only rated for 15 amps so what would you need to use in the US then ?

The receptacle and plug must be Horsepower rated, in addition to the Ampere rating.

(That's probably true in Canada also)

 

[engineer031]

That looks to be the same so the chart says 3 HP at 230 V is 17 amps so when I said to use a 20 amp breaker that looks like it would be what is needed.
Am I missing something else here ?

 

[wyliesdiesels]

That looks to be the same so the chart says 3 HP at 230 V is 17 amps so when I said to use a 20 amp breaker that looks like it would be what is needed.
Am I missing something else here ?

Yes you are. Its called in-rush current.

A 20a breaker for a 3HP motor will most likely trip due to the in-rush amps(4x-6x FLC) of the motor...

 

[keith5064]

I haven't had the 20a breaker trip thus far, but if it does I should be able to add a 30 amp breaker with the 10 gauge wire I have...

I'm thinking an armoured cable (ac/bx) coming out of a junction box, should be able to fit into the hold down clamp of the pressure switch...

Sent from my XT1080 using Tapatalk