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Compressor Wiring Question

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73Midget

73Midget

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I just purchased a new Ingersoll-Rand air compressor (see specs below) last Friday and am in the process of wiring 220v and installing air lines around my garage. I just want to be sure what I am thinking of doing is what I should be doing.

Compressor:
Ingersoll-Rand SS5N5
80 Gal
18.1 CFM @ 90
Max PSI: 135
5 (true) HP
230V

I plan on running a line from my main panel to a single breaker sub just for the compressor. The run from the main box to the garage is about 70ft. I plan on using #8/3 wire to the sub. Main panel will have a 40Amp breaker and the sub from the compressor 30A. Then #10/2 4ft to the compressor. Does this sound correct and will a 30A breaker in the garage be enough to handle the compressor load at startup? Compressor’s FLA rating is 22.5A.

For the air lines I plan on using Âľ M copper with sweat fittings. My neighbor is a plumber and that would be fine for pressure up to 200 - 250 lbs, compressor is only rated to 135 lbs. I think OSHA requires K or L copper but this is just going to be in my garage.

Your thoughts???

Thanks,
 
That will work, and if anything is a little overkill with the 40A sub. Just remember that if it truly is a sub and not just a fused / breaker disconnect it needs to be have a separate ground bar kit added for code compliance. 30A should be fine on a 5HP motor at startup.

As far as piping, the limiting factor really is the sweated joints. ¾” drawn copper, type M is good for 611 psig in the 100’F to 250’F temperature range, but a 50/50 tin-lead joint at 100’F on a ¾” joint is only good for 200 psig and drops to 150 psig at 150’F. 95-5 tin-antimony is much better at 500 psig and 400 psig respectfully.

Just be sure you put in some type of flexible connection between the compressor and the rigid piping to reduce fatigue. As far as piping it up, install a tee in the line with the branch pointed up and then double 90 down to the use point to reduce the amount of condensate that you draw into the tool / gun and install low point drains at the ends to bleed condensate.

Just some thoughts.
 
Hey Greg, Is there a reason that your going with copper lines as opposed to PVC? I was always told that you would get less condensaion with a PVC line than you would get with a copper line because PVC will not disapate the heat as well, therefore not condense as much. Just my $0.02
 
First off thanks for the input everyone.

There are a few reasons why I chose copper. The first being exactly what you mentioned above, copper dissipates heat better than PVC. This will cause the air to cool and condense in the line and eventually run into one of the lower drain points before it reaches the filter or tool you plan on using. The second reason was the safety factor. My garage is quite small and there is a greater risk of banging into a PVC line and possibly cracking it, very small chance I know but I want to be safe. Plus I enjoy working with copper.

Thanks again,
 
[ QUOTE ]
...Is there a reason that your going with copper lines as opposed to PVC? ...

[/ QUOTE ]PVC is brittle. When it fails in a compressed gas system it can fail catastrophically, dispersing shrapnel at high speeds. That's a very bad thing if you happen to be standing anywhere near by.


PC.
 
Greg,

One thing you didn't mention is plug: Will you be wiring a receptacle on the wall and a plug on the compressor or hard wiring the compressor to the wall? We just put a 230V Kobalt compressor from Lowes in at my father's house (christmas present) and put a plug on the wall since he's moving in 6 months. Being the geniuses we are we decided to use a NEMA 6-30 plug since it was a 30amp run, then had to weld something on the Sunbeam and since our 110V was about an hour away on loan we borrowed a neighbor's 220V welder and discovered that welders seem to all be NEMA 6-50. So, if you might ever want to temporarily plug a welder in be sure to use a NEMA 6-50 receptacle instead of a 6-30. Of course, this doesn't matter if you're also putting in a receptacle for a welder or if you're hard wiring it.

Also, your compressor manual should list specs for the breaker requirements. Our Kobalt (which appears to be made by IR) is only 17A max draw.
 
No plug, going to direct wire to the box. However, I did run into a similar plug problem a few years back with a welder I borrowed.

Found the following chart listing Pressure-Temperature Ratings of Copper Joints from the Copper Tube Handbook. I thought it was quite interesting so I figured I'd share.

https://tinyurl.com/e4dz2
 
Well, I wired up the compressor this weekend (30A breaker w/ #10/2 about 3ft to the compressor). Flipped the breaker and was in business, so I thought….. Pressure built but the pressure switch did not activate to shut off the motor (should shut @ 135 but built to 155 before the safety valve kicked in and I killed the power.

I figured there might be a problem with the pressure switch. The sticker on the cover is slightly wrinkled as if it was bumped in shipping. Tried to adjust but no luck. Compressor will only kick on if I first push the breaker points together then switch on the power. My adjustments must have worked slightly because the compressor now shuts off @ 135psi. However, after it shuts off I can drain the tank to 0 and it will still not turn back on again.

Called the Ingersoll-Rand hotline. First question after asking for the model number was how I had it wired. When I said direct to 30A breaker using #10/2 the lady almost flipped. She said with that 5hp/230v/22.5 FLA I needed to have a 60A breaker with #6 to the compressor and I may have fried my pressure switch.

??Wouldn’t my breaker have tripped if the motor was looking for that much more power at startup??

After talking to her for a bit she calmed down and said she would send me another pressure switch. She said it was up to me how it was wired but if I kept it like I have it now the motor may not last as long as it should.

Anyone have any thoughts???

Thanks,
 
If the motor label says 22FLA (full load amps) then thats what you need to protect for. If the IR lady is saying something about 60 amps, either she dosnt know what shes talking about, OR the two of you were not talking about the same compressor. double check the I.D. plate on the motor and size the breaker accordingly. As far as wire size, that depends on FLA rating of the motor AND distance this motor is from the breaker, (voltage drop).
 
Thanks for the reassurance. I think the lady was just having a bad day. I took a closer look at the redulator yesterday and it looks as if there is a small part broken off inside. Should have the new one soon.

Thanks again,
 
I know you're getting a replacement switch, but can you give me the make / model on the pressure switch? The thing that has always bothered me about (residential) compressors is that they put motor load on the pressure switch instead of a separate magnetic starter that is designed to take the inrush current.
Chris
 
Chris,

Couldn't find anything that said "Model #" on the switch so I just took a picture of the label (link below). I was also reading up on magnetic starters today and it does seem like a better/safer setup.

As for the new switch. I called IR on Monday, switch was at my door on Tuesday. Now that's customer service. Replaced the old and the compressor is working great.

I am still curious about the magnetic starter.

https://www.positive-outlook.com/mg/switch.jpg

Thanks,
 
/Nerd engineer mode on/ I have a cut sheet for the 69J pressure switches, but they do not list the 69JG1 specifically and I can't decipher the part number to tell what it is rated for horsepower wise. It is interesting to note that the 69JG switch is only rated for 3 HP at 240VAC single phase. I realize the amperage rating is in line with your motor, but it is marginal in my opinion. I'm not trying to reinvent the wheel here, just curious. I emailed Hubbell and asked them for a spec sheet on that part number specifically and what the HP rating is. I'll let you know what they say. /Nerd engineer mode off/
Chris
 
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