New IR Compressor

[onewheat]

I just picked up a new IR 5 hp, 2-stage 80 gallon compressor at Tractor Supply on Friday. We brought it home and carried it to the second floor of my shop. That was actually easier than I thought it would be. Anyway... I haven’t installed it yet, but I find IR’s documents a bit thin in detail, so...

My electrician gave me a 60A circuit for the compressor terminated in a 30A plug. To wire this up, should I go with a Range plug (6/2 & 8/1) and just plug it in, OR get rid of the outlet and just hard-wire it?

Also, I remember reading something somewhere sometime about running a new compressor “unloaded” for a time to “break it in” but IR says put oil in it and that’s pretty much it. Thoughts?

I plan on mounting it to two 2x4s that span 4 joists (to distribute load and vibration) - I have engineered I-beams 12” on center - I’m not worried about load. I put it on the second floor mainly for space and so I didn’t have to listen to it. I plan on bolting through the 2x4 with isolation pads sandwiched in and then screwing the 2x4 down to the floor. Does this seem reasonable?




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[dw1]

looks like a 30 amp circuit, not a 60. The orange romex is 10 gauge wire, but it still should be OK, on a 5 HP motor you should have a disconnect switch and hard wire it in.

 

[LS6 Tommy]

looks like a 30 amp circuit, not a 60. The orange romex is 10 gauge wire, but it still should be OK, on a 5 HP motor you should have a disconnect switch and hard wire it in.

X2 on the disconnect and hard wire, that receptacle is not the right application anyway and I think the wire itself is not sized properly. Considering the electrician misapplied the receptacle, I'd double check to make sure you don't have a 60A breaker feeding 10Ga wire regardless of whether the circuit is sized properly for the motor.

Tommy

 

[mdkcal]

60 amp breaker with 10 ga wire is fine for a 5 hp motor as long as you have a disconnect switch with 30 amp fuses within view of the compressor. It should have come with recommended electrical connections.

 

[brihvac]

10 gauge wire is for 30 amp. A 60 amp breaker for 10 gauge is not ok. Your electrician should not have done that. Look it up for yourself you will see. Change the breaker to a 30amp. The compressor full load amps are only 21.5
https://www.usawire-cable.com/pdfs/NEC AMPACITIES.pdf

 

[jkeyser14]

Also, be warned that some of the motors used on the IR compressors have a history of catching fire. Do a quick google search. I found that out after the capacitor on my brand new one blew up a few years ago. Hopefully it has been fixed by now, I haven't looked in a few years.

Also, IR's warranty is a steaming pile of ****. When I tried to make a warranty for the capacitor blowing they told me it was because my electric service was bad (it wasn't) and they refused to cover it. I put in a different brand of starting cap and it has been great ever since.

 

[onewheat]

I have a 60 Amp breaker as in two 30A breakers hooked together. If I should have those swapped to two 15A breakers, I'm fine with that, as well as hard-wiring the compressor. So I should also have another disconnect switch next to the compressor? Like one of these switches? (in the thumbnail)



Or keep the 2-30A breakers and have a disconnect switch with 30A fuses is also a possibility? Like this - Siemens 30-Amp Fusible Metallic Safety Switch

 

[mdkcal]

Fused disconnect with 30 amp fuses

 

[MattT]

I have a 60 Amp breaker as in two 30A breakers hooked together.

I think/hope you've actually got a double pole 30A breaker. Or your lektrishun has handle tied a pair of single poles Might be best if you post a pic of the panel with cover removed.

 

[wyliesdiesels]

I just picked up a new IR 5 hp, 2-stage 80 gallon compressor at Tractor Supply on Friday. We brought it home and carried it to the second floor of my shop. That was actually easier than I thought it would be. Anyway... I haven’t installed it yet, but I find IR’s documents a bit thin in detail, so...

My electrician gave me a 60A circuit for the compressor terminated in a 30A plug. To wire this up, should I go with a Range plug (6/2 & 8/1) and just plug it in, OR get rid of the outlet and just hard-wire it?

Fire your electrician.

He has no clue what he is doing.

a 5HP motor needs 35a wire- #10 NM-b is too small as #10 NM-b is limited to 30a. Then you say he put it on a 60a breaker?

The outlet your "electrician" installed is not a GROUNDED outlet. It is an old NEMA 10-30 120/240v outlet for use on existing dryer circuits.

However, a 5HP motor needs to be hardwired as there are no NEMA outlets rated for more than 3HP.

looks like a 30 amp circuit, not a 60. The orange romex is 10 gauge wire, but it still should be OK, on a 5 HP motor you should have a disconnect switch and hard wire it in.

#10 nm-b is too small for a 5hp motor circuit.

60 amp breaker with 10 ga wire is fine for a 5 hp motor as long as you have a disconnect switch with 30 amp fuses within view of the compressor. It should have come with recommended electrical connections.

No #10 nm-b is too small and what code says 30a fuses are required?

I have a 60 Amp breaker as in two 30A breakers hooked together. If I should have those swapped to two 15A breakers, I'm fine with that, as well as hard-wiring the compressor. So I should also have another disconnect switch next to the compressor? Like one of these switches? (in the thumbnail)



Or keep the 2-30A breakers and have a disconnect switch with 30A fuses is also a possibility? Like this - Siemens 30-Amp Fusible Metallic Safety Switch

that is NOT a 60a breaker. A 2 pole 30a breaker with handle ties is still a 30a breaker.

DO NOT swap them to a 15a breaker. They will trip because the motor is 21a FLA.

You need a disconnect if the compressor is more than 50' from and not within sight of the breaker panel. Since it sounds like the breaker panel is not within sight of the compressor then yes you need a disconnect.

you could go with a cheap non fused Air conditioning disconnect as long as its rated for at least 5hp.

A fused disconnect is not necessary...

 

[wyliesdiesels]

Fused disconnect with 30 amp fuses

A fused disconnect is really overkill

 

[onewheat]

OK - my electrical terminology is obviously off. So...

I have a 2-pole 30A breaker - which should be correct.

I need to add a disconnect at the compressor since my breaker box is not in the line of sight. Something like this - 30 Amp 240-Volt Non-Fuse Indoor Safety Switch

It does not have to be fused because my breakers are rated correctly.

I will hard-wire from the safety disconnect to the compressor's pressure switch.
Would I use something like this? 1/2 in. x 6 ft. 10/3 Ultra-Whip Liquidtight Flexible Non-Metallic PVC Conduit Cable Whip
Should this wire be solid or stranded - or does it matter?

Do I need to have the wire from the breaker to the disconnect looked at - or is my 10ga NM-B sufficient?

 

[wyliesdiesels]

#10 nm-b is too small for code. You need 35a rated wire so #8 NM-b.

The disconnect needs a 5HP rating. Dont know if the one you linked to does

 

[Norcal]

That receptacle is a 30A but still wrong because it is a non grounding dryer device, it was only allowed for dryers and now only in existing installations done prior to the adoption of the 1996 NEC, and the circuit needs to be sized to the table in article 430 which means a minimum of 35A so when NM cable is used that means 8 AWG minimum as explained by Wyliesdiesels in previous posts.

 

[MattT]

#10 nm-b is too small for code. You need 35a rated wire so #8 NM-b.

Since the compressor is in what appears to be an uninsulated attic #8 might not be enough. Probably gets pretty hot up there in the summer.

Also wouldn't hurt to check the motor nameplate to see what ambient it's rated for.

 

[wyliesdiesels]

Since the compressor is in what appears to be an uninsulated attic #8 might not be enough. Probably gets pretty hot up there in the summer.

Also wouldn't hurt to check the motor nameplate to see what ambient it's rated for.

Very good point i didnt even think of.

So much wrong with this install its hard to think of it all.

 

[pancho400cid]

As for the rated ambient temp... the motor NP says 40 Deg C (104 Deg F)....

 

[onewheat]

So temperature affects what gauge wire I need too? How do you come up with the 35a needed rating?

 

[checkthisout]

Is a disconnect (within sight) still required if the compressor has an on/off switch on it?

 

[wyliesdiesels]

So temperature affects what gauge wire I need too? How do you come up with the 35a needed rating?

Yes temperature affects usable ampacity.

Wire for motor circuits is required to be sized at 125% of NEC code article table 430.248 and corresponding HP FLC rating.

5HP = 28a

28a * 1.25 = 35a

Then you need to figure the ambient temperature and adjust the ampacity of the wire according to the factor in the ambient temperature adjustment chart and make sure its rated for the needed ampacity.

The orange NM-b you have is already too small, then the ambient temp adjustment will further restrict it.

#8 NM-b may be too small

Remember, NM-b is limited to 60* ampacity.

If THHN in pipe was used, you could use small conductors vs nm-b.

Its very evident that your “electrician” did not factor in any of this.

Have you paid him already? I would make him come back and fix it.

Is a disconnect (within sight) still required if the compressor has an on/off switch on it?

Yes!

An on/off/auto switch on the compressor does not disconnect power to the compressor for servicing.

 

[onewheat]

I think, from what I understand, the disconnect is there to de-energize the circuit in case someone needs to work on it (the circuit). I guess the switch would work to work on the compressor but it would (or could) still be energized with 220v up to the pressure switch without the disconnect and without a line of sight to the breaker, I guess someone could always flip it on without a lockout/tagout on the breaker.

 

[wyliesdiesels]

I think, from what I understand, the disconnect is there to de-energize the circuit in case someone needs to work on it (the circuit). I guess the switch would work to work on the compressor but it would (or could) still be energized with 220v up to the pressure switch without the disconnect and without a line of sight to the breaker, I guess someone could always flip it on without a lockout/tagout on the breaker.

Correct

Thats why a disconnect is required

 

[onewheat]

If the spec plate on the motor says 21.5a (21.5a*125%= 26.9a), wouldn't a 30a be sufficient - discounting temperature? Or do you have to go by the generic 5 hp motor amp rating?

My electrician did all of this almost 6 years ago when we built the house. I don't remember exactly what details we discussed as I didn't have a specific compressor I was going to buy. I may have said I planned on a 5 hp compressor, but I honestly don't remember. I just knew I wanted 220v where he placed it.

 

[wyliesdiesels]

To be code compliant it needs to be sized by the FLC table in the NEC code.

 

[Terry D]

This is what separates a true electrician, from someone that just claims to be one.
Would your compressor run if you plugged it in to that, sure it would. Would it be the right way, absolutely not, and possibly be a potential hazard down the road, sure it would. That is the sad thing about electric, It can be installed wrong and still work, until something bad happens. There is reasons the NEC is written the way it is. Wyliesdiesels has described in this thread and numerous other threads how to properly wire these compressors. Do yourself a favor, wire it correctly, it will give you peace of mind.

 

[onewheat]

I don't have a problem changing anything in this setup to make it right. I'm just trying to understand it all.

 

[Terry D]

It is very confusing to understand if your not a electrician, and don't do this stuff every day. That is why when we don't understand something and don't feel comfortable doing it, we hire it out. In your case, the job your electrician did was not correct. It wouldn't even pass for a electric dryer circuit. To properly install that circuit in advance before the compressor was even purchased, he would have had to know the specs of that compressor to do it correctly. This compressor is not considered a appliance, so the circuit feeding it has to be figured out differently. The amperage rating on that motor has nothing to do with sizing the circuit to feed it. You must go to table 430.248 in the NEC for full load currents of single phase motors. So your 5 hp. motor at 230 volts has a FLC of 28 amps. Then you have to multiply that by 125%, which is 35 amps. Now you can properly size your wire, and if your using NM (romex) that would be a 8-2. To properly size and determine what kind of disconnecting means to use, you have to take your 35 amps that you calculated and also your 5 hp. rating on your motor. There is no plug attachment rated for 5 Hp. So the compressor has to be hard wired to the disconnecting means. As long as the disconnect is rated for at least 35 amps and 5hp. it is acceptable to use. So the only thing left to figure out is the size of the circuit breaker, in this case, it is not sized to the conductors it is protecting, it is sized to the FLC of the motor, which is 28 amps (taken from table 430.248 again) For you style breaker, the NEC will allow you to have a maximum size up to 250% of the FLC of that motor, this is found in table 430.52. You do not multiply by 125% for this. So 28 amps x 2.5 = 70 amps. That means you can go up to a 70 amp breaker for that compressor. It probably wont need that much, since you electrician already installed a 60 amp, use that. I would probably start with a 50 amp if the breaker wasn't already there. All of this is very confusing if you have never been taught it. Its not something everyone knows. This is why as electricians, we sit in class rooms to learn this, and keep re visiting these class rooms to keep up to date with the code changes. I sorry that you paid your hard earned money and received a shotty job like this. I have seen this many times. As I said before, there are reasons the NEC is written they way it is. Its for safety and keeping your place from burning down.

 

[MattT]

I don't have a problem changing anything in this setup to make it right.

Roughly how hot does is currently get up there in the summer? I suspect you'll be pushing, or exceeding, the ambient temperature limit of your motor. Also the compressor will dump a significant amount of additional heat into the space when it's running making matters even worse.

If you do run that compressor above it's rated ambient it will shorten the motor life. May also cause other problems too. So the first thing you need to do is make a call on whether to leave the compressor in the attic or move it.

 

[wyliesdiesels]

Terry, you may want to fix your last comment as the quote coding got cut off so now when someone quotes you it will be screwed up....

It probably wont need that much, since your electrician already installed a 60 amp, use that. I would probably start with a 50 amp if the breaker wasn't already there. All of this is very confusing if you have never been taught it. Its not something everyone knows. This is why as electricians, we sit in class rooms to learn this, and keep re visiting these class rooms to keep up to date with the code changes. I sorry that you paid your hard earned money and received a shotty job like this. I have seen this many times. As I said before, there are reasons the NEC is written they way it is. Its for safety and keeping your place from burning down.

His electrician didnt actually install a 60a breaker. The OP was confused and thought a handle tied 30a double breaker was a 60a breaker. The OP has in fact a 30a double pole breaker.

This may or may not nuisance trip when the compressor starts...so a larger breaker may be needed...

 

[Terry D]

Terry, you may want to fix your last comment as the quote coding got cut off so now when someone quotes you it will be screwed up....



His electrician didnt actually install a 60a breaker. The OP was confused and thought a handle tied 30a double breaker was a 60a breaker. The OP has in fact a 30a double pole breaker.

This may or may not nuisance trip when the compressor starts...so a larger breaker may be needed...

Ok thanks I will fix that. I misunderstood the first post, thought it was a 60 amp 2 pole.

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[sberry]

Being willing to fix something right is a good thing. These have been miswired for decades with 10 cable and 30 breakers and really doubt anyone has burnt the shack down from it. My Bud had a 28A one he hooked to 10/30, I suggested he might blow a breaker but it never happened cept one time the start circuit had a problem and the 22A units I never see one trip it up that wasn't faulty.
Some of the MFGs now making something called "special" and I bet the idea was to get around it and allow for the use of 10 cable.
But, some of the answers make one wonder how many threads we see about this here? The op is doing just what he should, pecking away until he understands or more importantly does it the way its sposed to.

 

[wyliesdiesels]

Ok thanks I will fix that. I misunderstood the first post, thought it was a 60 amp 2 pole.

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oh i thought the same thing since he said it was. then he came back later and said it was 2 30a breakers next to each other

 

[onewheat]

Roughly how hot does is currently get up there in the summer? I suspect you'll be pushing, or exceeding, the ambient temperature limit of your motor. Also, the compressor will dump a significant amount of additional heat into the space when it's running making matters even worse.

If you do run that compressor above it's rated ambient it will shorten the motor life. May also cause other problems too. So the first thing you need to do is make a call on whether to leave the compressor in the attic or move it.

I will probably be pushing the temp rating of the motor in the heat of the summer. It may hit 110° when it's really hot here but typically if it's that hot, I'm not working in the garage during the day anyway. It's more of an unfinished second floor than an attic. I do have 4 windows up there and it is a pretty large space. I don't anticipate a ton of use with the compressor so duty cycle on it will be at the low end, as well.

 

[wyliesdiesels]

i would get a fan and aim it at the compressor motor and pump

 

[Tunajoe]

Curious if condensation will be an issue with the attic heat

 

[AntonLargiader]

Does the motor itself say 5HP or is the 5HP just on some marketing sticker?

 

[Terry D]

Does the motor itself say 5HP or is the 5HP just on some marketing sticker?

First post shows picture of motor name plate, 5 hp.

 

[onewheat]

Curious if condensation will be an issue with the attic heat

Probably - when it's high humidity here. I'll figure something out for that if/when the time arises. I think that may be an issue here mid-summer no matter where the compressor is in the garage. It gets awfully humid in the summer.

 

[GRB]

Higher humidity actually makes the air moving across the cooling fins cool a bit better. The denser air can absorb more heat. It is just the opposite of a person trying to get cool by evaporation.
The higher humidity does create more of a problem with water condensing in the tank and lines.
Thermostatically operated fan pulling air out of the very top helps keep the compressor cool along with the rest of the garage.

 

[checkthisout]

What do they in Vegas where regular ambient air temps can be 110 degrees?

Air condition the compressor room?