New IR Compressor

[pancho400cid]

I'd say don't worry about temperature or humidity... assuming the temp is not just ridiculous. Occasionally going over 40 Deg C is not going to grossly reduce the motor life.

Moisture in the air should be handled as it would be in any compressor set-up - by a filter/separator on the pressure piping. You also need a tank drain with drain piping routed to let water out where it doesn't hurt anything. That's always the case - I doesn't matter that you are in an attic.

Motor insulation life is a function of time and stress. Temperature is one thing that stresses insulation. Say you motor lasts 8 years instead of 10... So what? I guess you could move a little air through your attic setup with a Walmart box fan if you wanted.

 

[onewheat]

So, if I update my wire to something like this - 8-2 Southwire Romex

To a box something like this - Siemens-60-Amp-Non-fusible-Metallic-Safety-Switch

And from the box to the compressor with something like this - Southwire 3/4"x6' 8/2 Flexible Non-Metallic Conduit Cable Whip

I should be good?

If I leave my breaker as a 2-pole 30a, do I risk anything other than nuisance trips? If I encounter these, then I can just bump to a 2-pole 40a, correct?

 

[exranger06]

The Romex looks good.
I'd use this disconnect instead:
https://www.homedepot.com/p/GE-60-Amp-240-Volt-Non-Fuse-Metallic-AC-Disconnect-TFN60RCP/100674085
Much cheaper and gets the job done just fine.
For the liquid-tight conduit, you can use 10 gauge wire. The THHN wires in it have a higher temperature rating, so you can use smaller wire than the Romex.
Yes, you can swap the breaker for a 40 amp one no problem.

 

[onewheat]

I'd use this disconnect instead:
https://www.homedepot.com/p/GE-60-Amp-240-Volt-Non-Fuse-Metallic-AC-Disconnect-TFN60RCP/100674085
Much cheaper and gets the job done just fine.

I looked at a disconnect like that and wasn't sure if the A/C types were ok to use (code-wise) or not but if you look in the specs for it, it states - "Compatible with copper or aluminum lug wire range 14-3" so I figured it wouldn't work for 8 ga. wire

 

[wyliesdiesels]

I looked at a disconnect like that and wasn't sure if the A/C types were ok to use (code-wise) or not but if you look in the specs for it, it states - "Compatible with copper or aluminum lug wire range 14-3" so I figured it wouldn't work for 8 ga. wire

Why wouldnt it work for #8? Its rated for #3...

As far as disconnect ratings go, it needs to be rated for the same or higher HP as the motor...

 

[Terry D]

So, if I update my wire to something like this - 8-2 Southwire Romex

To a box something like this - Siemens-60-Amp-Non-fusible-Metallic-Safety-Switch

And from the box to the compressor with something like this - Southwire 3/4"x6' 8/2 Flexible Non-Metallic Conduit Cable Whip

I should be good?

If I leave my breaker as a 2-pole 30a, do I risk anything other than nuisance trips? If I encounter these, then I can just bump to a 2-pole 40a, correct?

You can leave the 2-pole 30. You could go all the way up to a 70 amp and still be code compliant.

 

[sberry]

I was going to a job where a former county electric inspector was at. I fix up a couple of cords just in case and when I get there is a dual motor 5 hp comp, 10 cord with a welder plug on the end.

 

[onewheat]

Why wouldnt it work for #8? Its rated for #3...

As far as disconnect ratings go, it needs to be rated for the same or higher HP as the motor...

I was reading that as up to a 14/3 wire - not as in a 3 ga-14ga wire range. It seemed odd to only go to a 14ga wire on a 60a disconnect, but I am definitely not fluent in "electrician" so I just went with it.

The original disconnect I was looking at was a 30a but it does say up to 7.5 HP on the cover plate - so if I'm upgrading the wire from 10ga to 8 ga because of the larger current capacity, would the other box still be sufficient, since it does say up to 7.5 hp?

GE 30 Amp 240 Volt Non-Fuse Indoor Safety Switch

If you zoom in on the cover plate photo - this does say "30 Amp 240V AC Max 7.5 HP"

Also - I really want to thank all of you guys who have stuck with me to explain this in layman's terms until I finally understood it all. I really appreciate it!

 

[onewheat]

The original disconnect I was looking at was a 30a but it does say up to 7.5 HP on the cover plate - so if I'm upgrading the wire from 10ga to 8 ga because of the larger current capacity, would the other box still be sufficient, since it does say up to 7.5 hp?

Nevermind - I just found a Spec Sheet on the box and it says the NEMA Type 1 30a disconnect (GE TGN3321) is only rated for 3 hp in Single-Phase but 7.5 hp in 3-Phase but the 60a disconnect (GE TGN3322) is rated for 10hp Single-Phase - but there is a footnote - so I'm confused again. What is "Service Equipment"?

Footnote - "Not suitable for use as service equipment. Solid neutral not available"

GE Spec Setter Safety Switches - Page 5 in the center of the page

 

[Terry D]

Nevermind - I just found a Spec Sheet on the box and it says the NEMA Type 1 30a disconnect (GE TGN3321) is only rated for 3 hp in Single-Phase but 7.5 hp in 3-Phase but the 60a disconnect (GE TGN3322) is rated for 10hp Single-Phase - but there is a footnote - so I'm confused again. What is "Service Equipment"?

Footnote - "Not suitable for use as service equipment. Solid neutral not available"

GE Spec Setter Safety Switches - Page 5 in the center of the page

It cant be used a main disconnect for a building or panel

 

[onewheat]

It cant be used a main disconnect for a building or panel

But good for a disconnect at a compressor - excellent!

Thanks Terry

 

[Bert_]

I was reading that as up to a 14/3 wire - not as in a 3 ga-14ga wire range. It seemed odd to only go to a 14ga wire on a 60a disconnect, but I am definitely not fluent in "electrician" so I just went with it.

The original disconnect I was looking at was a 30a but it does say up to 7.5 HP on the cover plate - so if I'm upgrading the wire from 10ga to 8 ga because of the larger current capacity, would the other box still be sufficient, since it does say up to 7.5 hp?

GE 30 Amp 240 Volt Non-Fuse Indoor Safety Switch

If you zoom in on the cover plate photo - this does say "30 Amp 240V AC Max 7.5 HP"

Also - I really want to thank all of you guys who have stuck with me to explain this in layman's terms until I finally understood it all. I really appreciate it!

It's only rated for 7.5hp on 3 phase. The label inside the cover will list the single phase rating which will be 3hp on 240V

 

[onewheat]

Ok - I removed my 10/2 wire and have my 8/2 wire run in place (not hooked up yet). My disconnect box was delivered and I was going to wire it up. Is there an order the wires should be in R to L in the box (ground centered?) or doesn’t matter as long as it’s the same on the Line and Load side obviously?






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[Bert_]

Ok - I removed my 10/2 wire and have my 8/2 wire run in place (not hooked up yet). My disconnect box was delivered and I was going to wire it up. Is there an order the wires should be in R to L in the box (ground centered?) or doesn’t matter as long as it’s the same on the Line and Load side obviously?


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Ground does not go through the switch. They should be terminated on a lug in the lower portion of the box. Ground is NEVER switched.

 

[Terry D]

That is a 3 pole disconnect, you only need a 2 pole. You can use it. I dont think it is a violation, you just spent more money than needed to. Your ground does not go on any of the poles, just your 2 hots. So you will have the 3rd pole with nothing on it. You will need a ground bar to install in the disconnect to land your two grounds. That will attach right to the can. If you can return it and get a two pole, it might save you some money

Sent from my SM-G960U using The Garage Journal mobile app

 

[onewheat]

OK - I thought that seemed weird, but that's why I ask. Grounds are tied, otherwise no order specified on the others, right? So I'll just use the outside two lugs. Too much hassle to return and the only others they really have are like A/C disconnects, which aren't very intuitive for some people. I like this one as it's very obvious for Off/On - although realistically, no one like that will ever be near it.

 

[Bert_]

GE doesn't make this style non fused disconnect in 2 pole, only 3 pole. It would probably cost more if they made 2 and 3 pole disconnects separately.

 

[onewheat]

I didn't see any non-fusible ones for under $120 in 2-pole (forget the brand) and a fusible 2-pole from Square D was probably $20 more with fuses. As long as I'm good with this one, I'm happy.

 

[wyliesdiesels]

OK - I thought that seemed weird, but that's why I ask. Grounds are tied, otherwise no order specified on the others, right? So I'll just use the outside two lugs. Too much hassle to return and the only others they really have are like A/C disconnects, which aren't very intuitive for some people. I like this one as it's very obvious for Off/On - although realistically, no one like that will ever be near it.

Non-fused A/C disconnects are the perfect budget friendly option for this. As long as its rated for the same or higher Hp as the compressor, then youre good to go. You could always label it- compressor disconnect- pull out.

But I assume you would be the only one using it so does it really need to be intuitive for others?

 

[sberry]

Tie grounds together and to the box.

 

[onewheat]

Non-fused A/C disconnects are the perfect budget friendly option for this. As long as its rated for the same or higher Hp as the compressor, then youre good to go. You could always label it- compressor disconnect- pull out.

But I assume you would be the only one using it so does it really need to be intuitive for others?

I couldn't readily find the HP ratings for the A/C disconnects and I did happen across the ratings for the box I ended up with, so I just went with it. It was only $45.

Yes - realistically, I will be the only one who ever uses it and most likely, I will probably never use it either. It does make me 'code compliant' though so I'm sure I'll sleep better at night knowing this.

I did get a short grounding bar/bus bar (whatever it's called) that I can screw into the box and tie the grounds into as well. I'm gonna sleep like a baby!

 

[theoldwizard1]

Non-fused A/C disconnects are the perfect budget friendly option for this. As long as its rated for the same or higher Hp as the compressor, then youre good to go. You could always label it- compressor disconnect- pull out.

I'll never understand why these are not used more often !