What size breaker/wire for a 5hp motor

[blanning]

I need to put in circuits for a tablesaw, bandsaw, and planer, all 5hp.  Some people say to put in 40amp/#8, others say 30amp/#10 is fine.  The machines will probably be about 40 feet from the panel.  What does everyone think?

[MstrCarpenter]

A 5hp. air compressor probably draws more amps at start-up than the other equipment. They're usually less than 25 FLA. Check the data on the equipment you need to power and go higher from there.

[fredhargis]

I have a 5 HP SS that has about 30' of wire between it and the panel and it runs on #10 wire and a 30 amp breaker. MY DC (also 5 HP) is closer to 50' of wire and it's also on #10 wire and a 30 amp breaker. The DC really draws the juice on start up as it brings the impeller up to speed and I've never had a problem tripping the breaker. But I have seen some 5 HP tools spec a 40 amp circuit in the manual. I don't really see that as necessary, probably a CYA move by the vendor..

[jteneyck]

I need to put in circuits for a tablesaw, bandsaw, and planer, all 5hp.  Some people say to put in 40amp/#8, others say 30amp/#10 is fine.  The machines will probably be about 40 feet from the panel.  What does everyone think?

The Grizzly manual for my 5 hp bandsaw says a minimum 30 amp circuit with #10 gage wire.  That's what I have it on, with a run of about 30 ft from the panel.  6 years or so, never a problem.  

John

[blanning]

The Grizzly manual for my 5 hp bandsaw says a minimum 30 amp circuit with #10 gage wire.  That's what I have it on, with a run of about 30 ft from the panel.  6 years or so, never a problem.  

John

After posting, I figured if I'm installing new power, I may as well go with #8 and 40 amps.  It's more money but not that much more it looks like.  On the other hand, if I put in #10, I can always pull out the wire and run #8 later if it becomes a problem.

I guess the best thing is to just do what the manual says.

[jteneyck]

After posting, I figured if I'm installing new power, I may as well go with #8 and 40 amps.  It's more money but not that much more it looks like.  On the other hand, if I put in #10, I can always pull out the wire and run #8 later if it becomes a problem.

I guess the best thing is to just do what the manual says.

If you plan on running multiple machines at the same time on that line, then you will need a larger breaker and heavier wire.  If it's just the bandsaw, however, I don't see why you would. 

John

[Bob10]

After posting, I figured if I'm installing new power, I may as well go with #8 and 40 amps.  It's more money but not that much more it looks like.  On the other hand, if I put in #10, I can always pull out the wire and run #8 later if it becomes a problem.

I guess the best thing is to just do what the manual says.

I have never seen anyone go back with larger wire. If you plan on running one machine at a time the 30 amp breaker should be good or you need to plan on having an additional breaker to run whatever else you may run at the same time. Shop tools at my place are in a separate panel which can be powered off with by a single switch. I never worry about the wiring overheating.

[fredhargis]

Give this some thought, I don't think there is a NEMA 40 amp plug/receptacle setup, they list a 30 amp, then it goes to 50 amps.

[Roly]

Give this some thought, I don't think there is a NEMA 40 amp plug/receptacle setup, they list a 30 amp, then it goes to 50 amps.

Correct, but you can use a 50 amp receptacle on a 40 amp circuit or hard wire the saw.  Roly

[Brian in sunny FL]

This thread made me thing of something with the way my garage was wired up by the previous owner who would park an RV in there and I think someone ran a business too.

I have a 50A outlet wired to a 50A breaker.  They also tapped into that same feed and installed a 20A outlet on the same breaker.  Is there any safety issues having a 20A circuit on a 50A breaker?  Just thinking of drawing more current than the outlet can handle without blowing the breaker.  More in the even of a failure or short, not so much using a tool that pulls more than 20A.  I would replace the outlet and wiring if I did that.