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Wiring up a Compressor

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bczygan

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Of course there are the choices of hard wiring and plug and cord with an outlet.

My second decision is whether to wire it up for a future, bigger compressor.

The third consideration is for wiring of 240V circuits. Someone suggested wiring them all with #10, so they can be used for that and anything smaller.

Note that this is an oil-less compressor, and I will be using it temporarily, until I get a bigger one operational.

OK, the compressor is:

2002 Craftsman Industrial 60Gal. vertical
919.165612
7 Max. Developed HP
2.9 Running HP
240/60/1 Voltage-Single Phase
15 Amps Minimum Branch Circuit Requirement
Time Delay Fuse Type

http://www.searspartsdirect.com/partsdirect/part-model/Craftsman-Parts/Air-compressor-Parts/user-manuals/manual-downloads/Model-919165612/0247/0703000?modelNumber=919165612&diagramPageId=&documentId=

So, for a quick and dirty quick hook up, what do I do? Wire size, breaker etc.

Bill
 
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MoonRise

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bczygan said:
What bothers me is the 7 Max. Developed HP.

Does the time delay fuse or the use of a breaker take care of that? Is that the startup current of the motor?
Click to expand...

That '7 max developed HP' line is pretty much advertising BS.

(take the motor, stall it to zero RPM at full line voltage, multiply the locked rotor current times the line voltage and then calculate what that wattage would 'equal' in electrical motor HP and call it 'max developed HP').

A time-delay fuse or a breaker should be able to handle the 'normal' motor startup current inrush.

Per the 'specs' there, a 240V circuit with a minimum 15 amp breaker should be able to run that compressor. Anything 'bigger' on the breaker will also handle the electrical needs of the compressor.

Wire size has to be a minimum size in accordance with the fuse/breaker (remember, the fuse/breaker is there to protect the wire). Up-sizing the wire may be needed if the wiring distance is 'long', to compensate for voltage drop in the wire.

Me? I'd probably go for the 30 amp circuit with 10 AWG wire and a 6-30R outlet/receptacle just to be 'usable' with more things down the road. More equipment options there than with a 240V 15 amp circuit. YMMV.
 
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dawg69

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I have that same compressor and have it wired with #10 thhn in conduit and a 30A breaker. I've had no issues so far.

It's a pretty good compressor performance wise, but it is LOUD. :eek:

With 20/20 hindsight I would never buy a direct drive oilless compressor again merely because of the noise issue.
 
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bczygan

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MoonRise said:
That '7 max developed HP' line is pretty much advertising BS.

(take the motor, stall it to zero RPM at full line voltage, multiply the locked rotor current times the line voltage and then calculate what that wattage would 'equal' in electrical motor HP and call it 'max developed HP').

A time-delay fuse or a breaker should be able to handle the 'normal' motor startup current inrush.

Per the 'specs' there, a 240V circuit with a minimum 15 amp breaker should be able to run that compressor. Anything 'bigger' on the breaker will also handle the electrical needs of the compressor.

Wire size has to be a minimum size in accordance with the fuse/breaker (remember, the fuse/breaker is there to protect the wire). Up-sizing the wire may be needed if the wiring distance is 'long', to compensate for voltage drop in the wire.

Me? I'd probably go for the 30 amp circuit with 10 AWG wire and a 6-30R outlet/receptacle just to be 'usable' with more things down the road. More equipment options there than with a 240V 15 amp circuit. YMMV.
Click to expand...

MoonRise,
Thank you so much!

You have educated and reassured me and I will do exactly as you say! Time to fire up a Lowes $10 off $50 and get some wire and such.

Of course I will need a wire with 3 conductors and a ground, right?

Thanks again,

Bill
 
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bczygan

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dawg69 said:
I have that same compressor and have it wired with #10 thhn in conduit and a 30A breaker. I've had no issues so far.

It's a pretty good compressor performance wise, but it is LOUD. :eek:

With 20/20 hindsight I would never buy a direct drive oilless compressor again merely because of the noise issue.
Click to expand...

It probably needs a rebuild too. But got it for $60, so........Will do for temp.

Just need something better then the Porter Cable pancake. Might put it on the back porch.
 
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alfredeneuman

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You just need 2 conductors and a ground. 10-2 NM

There is no neutral connection on the motor.
Just tape the white wire to a color (not green) at the terminations.
 
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bczygan

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alfredeneuman said:
You just need 2 conductors and a ground. 10-2 NM

There is no neutral connection on the motor.
Just tape the white wire to a color (not green) at the terminations.
Click to expand...

I just looked at the cord on the compressor itself and it says 16/3. Does that mean 2 conductors and a ground?

And that seems pretty small. Just like the wire on a lamp is very small compared to the circuit it is plugged into.

Is the thinking that anything plugged in can be unplugged?

Bill
 
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bczygan

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bczygan said:
I just looked at the cord on the compressor itself and it says 16/3. Does that mean 2 conductors and a ground?

And that seems pretty small. Just like the wire on a lamp is very small compared to the circuit it is plugged into.

Is the thinking that anything plugged in can be unplugged?

Bill
Click to expand...

Just checked, black, white and green.
 
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wyliesdiesels

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Modesto, CA
MoonRise said:
That '7 max developed HP' line is pretty much advertising BS.

(take the motor, stall it to zero RPM at full line voltage, multiply the locked rotor current times the line voltage and then calculate what that wattage would 'equal' in electrical motor HP and call it 'max developed HP').

A time-delay fuse or a breaker should be able to handle the 'normal' motor startup current inrush.

Per the 'specs' there, a 240V circuit with a minimum 15 amp breaker should be able to run that compressor. Anything 'bigger' on the breaker will also handle the electrical needs of the compressor.

Wire size has to be a minimum size in accordance with the fuse/breaker (remember, the fuse/breaker is there to protect the wire). Up-sizing the wire may be needed if the wiring distance is 'long', to compensate for voltage drop in the wire.

Me? I'd probably go for the 30 amp circuit with 10 AWG wire and a 6-30R outlet/receptacle just to be 'usable' with more things down the road. More equipment options there than with a 240V 15 amp circuit. YMMV.
Click to expand...

breakers for motor circuits do not protect the motor or the wire from overcurrents. That is the job of the overload relay(if equiped with a starter) or overload built into the motor(red reset on motor)...the breaker is only for short circuits and ground faults...
 
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Charles (in GA)

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alfredeneuman said:
Cord is counted by the total number of conductors, including the ground.
On NM cable the ground isn't counted.
Click to expand...

To expand on this somewhat. Cord, flexible, such as SO or one of many other variations, has ALL insulated wires. The designation counts all insulated wires, no matter the color, so a a white, black and a green is 16/3.

Cable is designed to be permanently installed and will have a BARE ground wire, thus the designation, 12/2 w/grd. It has two insulated wires, a white and a black, and a bare ground.

Charles
 
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bczygan

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Aceman said:
Does the cord have a molded factory cord end on it?
Click to expand...

No.

I'm going to pick up an L6-30p and an L6-30

785007855258lg.jpg


785007857733lg.jpg


6957064500882lg.jpg


I'm going to surface mount an exterior Carlon box for the outlet on my brick garage wall..

There are plugs and outlets with 4 connections. What are they used for?

Bill
 
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wyliesdiesels

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Thats gonna be a little small. I would use a double gang box.

And no i cant think of a use for a NEMA 14-x receptacle in a shop except for a range if u do powder coating...
 
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bczygan

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bczygan said:
Could I use this box?

http://www.lowes.com/pd_130898-53911-E381DRL_0Z1z10ydb__?productId=3646224&pl=1&Ntt=electrical+boxes

034481065708lg.jpg
Click to expand...

Was afraid that the box pictured wouldn't have a big enough hole for the wire, so switched it for the 3/4" one without threads, so just glue in connection. Also, the one shown had an opening on the top that wasn't needed.

The outlet fit perfectly, although #10 tests your hand strength when bending it. Surprising how small the 50' coil is though. Now I need to drill some brick.

Bill
 
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