what size breaker to use with this?

[Spyider]

short story.. bought a 3ph 10hp air compressor.. replaced motor and sheave with a 7.5hp 1ph..
Now to get this wired up. says 34 amp.. so what size breaker should i use? i was thinking maybe a 50Amp, so when it kicks in it wont trip the breaker every time.. so that would mean i need to get some 8/2 wire ide assume correct?..

I have 100amp going out to the garage that was installed last summer into its own sub panel box. compressor will be roughly 30 ft from box, since ill be going up and over the ceiling and back down.. i'm gonna get a 50ft roll and just leave the extra up their so if i ever move.. ill simply just pull all 50ft back out to re use.. lol.

 

[AZ Garage]

short story.. bought a 3ph 10hp air compressor.. replaced motor and sheave with a 7.5hp 1ph..
Now to get this wired up. says 34 amp.. so what size breaker should i use? i was thinking maybe a 50Amp, so when it kicks in it wont trip the breaker every time.. so that would mean i need to get some 8/2 wire ide assume correct?..

34A*1.25% = 42.5A

A 50/2 breaker will suffice. Don't have my wiring guide in front of me, but I think #8s will work.

 

[wyliesdiesels]

Wire for motor circuits are sized @ 125% of NEC table FLC NOT motor nameplate FLA or FLC(in your case 34a)...

For 7.5HP this means 40a * 125% = 50a rated wire. 8/2 NM-b is too small. U need either 6/2 NM-b or #8 THHN in conduit.

Is the breaker panel visible from the compressor? If not u need a disconnect.

Breaker can be max 250% NEC table FLC. But u dont need to go that high. Start with a 40a. If it nuissance trips go to a 50a.

Do u have a mag starter?

 

[Spyider]

Yes i can see box from compressor.. Right across from it..
Yes it has a mag starter.
So 8/2 wire is too small your saying if i used a 50a ?..

 

[Spyider]

So i know.. I thought it was
8ga- aluminum
6ga- copper
? Ithor way im doing copper so i guess this means i need to get some 6/2..

 

[ddawg16]

Wire for motor circuits are sized @ 125% of NEC table FLC NOT motor nameplate FLA or FLC(in your case 34a)...

For 7.5HP this means 40a * 125% = 50a rated wire. 8/2 NM-b is too small. U need either 6/2 NM-b or #8 THHN in conduit.

Is the breaker panel visible from the compressor? If not u need a disconnect.

Breaker can be max 250% NEC table FLC. But u dont need to go that high. Start with a 40a. If it nuissance trips go to a 50a.

Do u have a mag starter?

^^ Yup ^^

 

[wyliesdiesels]

Yes i can see box from compressor.. Right across from it..
Yes it has a mag starter.
So 8/2 wire is too small your saying if i used a 50a ?..

It has NOTHING to do with the breaker size.

Breakers for motor circuits DO NOT protect the wire or motor. That is the job of the integral overload in the motor or in your case the overload relay in the starter.

NM-b is limited to the 60* c ampacity so #8 NM-b is only good for 40a. U need 50a rated wire to be code compliant so u either need 6/2 NM-b or #8 THHN in pipe...

So i know.. I thought it was
8ga- aluminum
6ga- copper
? Ithor way im doing copper so i guess this means i need to get some 6/2..

#8 AL has the same ampacity as #8 NM-B...

Not sure what youre trying to say here...