Quincy air compressor wiring help

[gotboosthatch]

Hey guys how would you recommend I install my Quincy 230v air compressor model qt-54.

What size breaker/wiring etc?


Thanks for your help

 

[kevs79]

Your going to need info on the motor itself for anyone to give you any advice. Just take a pic of the nameplate on the motor. BTW I'm probably no help but just know that is what the others will need to help you out.

 

[gotboosthatch]

https://www.aircompressorsdirect.co...or/p855.html?gclid=CLSsqs3NndICFRNWDQod3t4J3A

Here's a link to my compressor

 

[ArtC]

Per the specs you should use a 50 Amp breaker. The distance from your electrical panel to the compressor will determine the size of the wire needed.


Sent from my iPhone using Tapatalk

 

[gotboosthatch]

Per the specs you should use a 50 Amp breaker. The distance from your electrical panel to the compressor will determine the size of the wire needed.


Sent from my iPhone using Tapatalk

I'd say 50ft.

 

[md21722]

Just like every other 5 HP compressor.

#10 THHN (in conduit) or #8 NM-b (Romex).

30A breaker should work fine, 40A is probably more commonly used, up to 70A is allowed by code.

Disconnect required if panel is out of sight / more than 50 feet away.

Must be hard wired, no plugs allowed.

 

[wyliesdiesels]

wire for motor circuits is sized @ 125% NEC FLC.

For 5HP this means 35a rated wire- #8/2 NM-b or #10 THWN.

Breaker can be max 250% of NEC FLC.

50' is not a concern for voltage drop.

Will need a disconnect if breaker panel is not within sight of and further than 50' from the compressor.

Compressor should be hardwired- no plug/outlet.

EDIT: MD beat me to it/was typing at the same time.

 

[gotboosthatch]

Yea breaker panel will be diagonal from from breaker panel in my garage 30x32

 

[gotboosthatch]

So 8/3 Romex 50amp breaker hardwired?

 

[wyliesdiesels]

You dont need 8/3 since u dont need the neutral. 8/2 would suffice. And u could try a 30a breaker and see if it holds. Otherwise 40a should be fine.

 

[gotboosthatch]

You dont need 8/3 since u dont need the neutral. 8/2 would suffice. And u could try a 30a breaker and see if it holds. Otherwise 40a should be fine.

Okay great. Thanks!

 

[exranger06]

OP, hope you don't mind if I hijack this thread for a moment. I also just bought a Quincy QT-54 and I have a question about wiring it. I bought it used and the previous owner didn't have any starter or capacitor wired to it. The motor was simply connected to the pressure switch, and the pressure switch was connected to the line power. Is that correct, or should I get a starter?

Also, I read that the motor needs some kind of overload protector, since in this case the breaker mostly protects ground faults (which is why it can be oversized for the wire). My motor has a thermal overload reset button on it. Is that the same thing? Do I need any additional protective devices?

 

[StevenMorgan]

I wrote this awhile back and hopefully helps answer some of your questions.

http://www.garagejournal.com/forum/showthread.php?t=309088

 

[Norcal]

OP, hope you don't mind if I hijack this thread for a moment. I also just bought a Quincy QT-54 and I have a question about wiring it. I bought it used and the previous owner didn't have any starter or capacitor wired to it. The motor was simply connected to the pressure switch, and the pressure switch was connected to the line power. Is that correct, or should I get a starter?

Also, I read that the motor needs some kind of overload protector, since in this case the breaker mostly protects ground faults (which is why it can be oversized for the wire). My motor has a thermal overload reset button on it. Is that the same thing? Do I need any additional protective devices?

If the pressure switch is rated for the compressor motor then it's fine, check the switch the data should be on the cover. If the motor has O/L protection from the factory, it's fine too.

 

[exranger06]

I snapped this picture this morning. It looks like it's rated for 26 FLA. I'm guessing this close enough to the 28 FLA the motor is rated at?

 

[wyliesdiesels]

Take a pic of the motor nameplate

 

[exranger06]

Here ya go

 

[roblouvasz]

I snapped this picture this morning. It looks like it's rated for 26 FLA. I'm guessing this close enough to the 28 FLA the motor is rated at?

I would suggest a starter. Once those contacts begin to arc and carbon up, they will act like a resistor and will cause the start up winding in the motor to draw more current and burn out the start up windings. Ask me how I know....

 

[wyliesdiesels]

I snapped this picture this morning. It looks like it's rated for 26 FLA. I'm guessing this close enough to the 28 FLA the motor is rated at?

so motor has a 21FLA not a 28FLA.

The 28a FLC talked about above is an NEC rating not a rating that will be on every 5HP motor.

SO the PS is rated for more amps than the motor FLA

I would suggest a starter. Once those contacts begin to arc and carbon up, they will act like a resistor and will cause the start up winding in the motor to draw more current and burn out the start up windings. Ask me how I know....

That is an option if the OP wants to spend the money. However this is a factory installed PS so not necessary.

 

[matt_i]

I would suggest a starter. Once those contacts begin to arc and carbon up, they will act like a resistor and will cause the start up winding in the motor to draw more current and burn out the start up windings. Ask me how I know....

Pretty sure the compressor is new, judging from the pictures. I don't think Quincy is going to sell you a piece of junk that's going to self-destruct in short order.

That said, its directionally better to have a motor starter, but I'd place it fairly far down the project list.

 

[exranger06]

Thanks guys. I bought the compressor used, but it's only about a year old and in new condition. The pressure switch is almost definitely factory installed. I may still install a starter; I haven't decided yet. Ok, I'm done with hijacking this thread now.

 

[exranger06]

Ok one more question: Since the motor is 21 FLA, do I use that number to determine wire size (21 x 1.25) or do I still use the 28 FLA from the NEC? I'm going to use Romex for part of the run where it's inside a wall, and conduit where it's exposed in the garage. Total distance roughly 50 ft.
Originally I was going to use 8/2 since 28 x 1.25 = 35 amps. Now I'm thinking I can use 10/2. And even if I do use 8/2, apparently 10 gauge THHN is fine in conduit, so would I splice the 8/2 Romex to 10 gauge THHN?

 

[Norcal]

You have to use the data from the NEC table.

 

[wyliesdiesels]

Ok one more question: Since the motor is 21 FLA, do I use that number to determine wire size (21 x 1.25) or do I still use the 28 FLA from the NEC? I'm going to use Romex for part of the run where it's inside a wall, and conduit where it's exposed in the garage. Total distance roughly 50 ft.
Originally I was going to use 8/2 since 28 x 1.25 = 35 amps. Now I'm thinking I can use 10/2. And even if I do use 8/2, apparently 10 gauge THHN is fine in conduit, so would I splice the 8/2 Romex to 10 gauge THHN?

U wire based on NEC table FLC.

So need 35a rated wire which is 8/2 NM-b or #10 THHN in pipe.

NM-b and THHN have different ampacities.

 

[exranger06]

Ok, so I can splice the #10 THHN to the 8/2 no problem?

 

[wyliesdiesels]

Yes.

And best to use stranded wire from the wall to the starter or PS.

 

[exranger06]

Thought of two more questions. I'm almost positive these will be the final questions.
1. Does the ground wire also need to be #10, or can I get away with using a smaller wire?
2. What size conduit should I run? In addition to the 2 hots and a ground for the compressor, I will also be running three #14 wires for a different circuit (3 way light switch) in the same conduit. I'll be using EMT conduit.

 

[Norcal]

Thought of another question: does the ground wire also need to be #10, or can I get away with using a smaller wire?

10 AWG is minimum.

 

[wyliesdiesels]

Per the specs you should use a 50 Amp breaker. The distance from your electrical panel to the compressor will determine the size of the wire needed.


Sent from my iPhone using Tapatalk

I looked through the manuals on quincy's site and did not see a recommended breaker.

That 50a recommendation, which is NOT a required size, may just be a distributor recommendation...

NEC allows the breaker to be max 250% of FLC so for a 5HP thats 70a...