Air compressor wiring question

[Toledo Mark]

I have an air compressor with a 6.5 maximum hp electric motor on 120v.  Sticker on the side says FLA 15.  I want to put it on its own breaker.  It will be about 45 feet from the panel.  What would be the best wire and breaker size?  10 gauge and 20 Amp?

[Gavin_Sons]

I have an air compressor with a 6.5 maximum hp electric motor on 120v.  Sticker on the side says FLA 15.  I want to put it on its own breaker.  It will be about 45 feet from the panel.  What would be the best wire and breaker size?  10 gauge and 20 Amp?

Yes, that would be exactly what I would use 

[Jess Tolbirt]

I have an air compressor with a 6.5 maximum hp electric motor on 120v.  Sticker on the side says FLA 15.  I want to put it on its own breaker.  It will be about 45 feet from the panel.  What would be the best wire and breaker size?  10 gauge and 20 Amp?

full load is 15, at 45 feet #12 on a 20 amp breaker will do just fine..i run mine off an extision cord,,(#12)

[MarkT]

Sorry Mark you don't have 6.5hp on a 120v compressor.  There was a scam a few years ago, of air compressor makers exaggerating their hp figures - and there was a class-action lawsuit on it.  My 240v single stage Campbell-Hausfeld was one with bogus claims - in this case 5hp. (My new compressor, also a Campbell-Hausfeld - is 80 gal 240v two stage, 22amp 5.28kw or 7.18hp but the sticker on the tank claims only 5hp. You have to go to 240v to get over 3 hp)  You can figure it yourself by using an online converter of the watts of the motor - which they can't lie about - directly to hp. If the plate gives the amps instead of watts you know watts is ampsXvolts.  They also designate on the plates (usually) 110v or 230v but if you meter it's actually 120 or 240.  I'll say this - using one of those converters, your 6.5hp motor would have to be rated at 40 amps or 4.78kw.  No 120v breakers are rated that high - 20 is the limit. I believe it's UL that limits 120v devices to 1500w or 12.5amp.  Or maybe it's not them.

https://calculator-converter.com/converter_metric_horsepower_to_kilowatt_hp_to_kw_calculator.php

[oldsmokey]

Agree. Thats a lot of advertised HP for 120 volt. 20 amp circuit should be sufficient but would verify the UL tag for rated draw.

[Toledo Mark]

Sorry Mark you don't have 6.5hp on a 120v compressor.  There was a scam a few years ago, of air compressor makers exaggerating their hp figures - and there was a class-action lawsuit on it.  My 240v single stage Campbell-Hausfeld was one with bogus claims - in this case 5hp. (My new compressor, also a Campbell-Hausfeld - is 240v two stage, 5.28kw or 7.18hp. You have to go to 240v to have that kind of hp)  You can figure it yourself by using an online converter of the watts of the motor - which they can't lie about - directly to hp.  I'll say this - using one of those converters, your 6.5hp motor would have to be rated at 40 amps or 4.78kw.  No 120v circuits are rated that high - 20 is the limit. I believe it's UL that limits 120v devices to 1500w or 12.5amp.  Or maybe it's not them.

https://calculator-converter.com/converter_metric_horsepower_to_kilowatt_hp_to_kw_calculator.php

I kind of figured that but was just going by what the sticker said on the side of the tank.

[MarkT]

I have a 11.5amp Shop Vac that claims "5.75 peak hp".  Actual calculates to 1.88hp and that's using the calculation at 120v not 110 (higher result). That's a 306% exaggeration. Being generous, the "peak" is their key word.  All motors draw more current on startup and breakers are designed to not blow from that startup current - whether you can then backwards-calculate the higher current draw to "peak hp" is a stretch in my book.  GFIC circuits might trip with that draw as they are designed to be more sensitive and blow quickly before the large short kills you.

[Bigwolf]

It has been a very common practice for companies to exaggerate the power of tools for farm or home use.  It is purely sales pitch.  Mark is correct.  His suggestion to use a conversion program from watts to hp is the best way to figure the wiring needed.

My compressor was advertised as 7 & 1/2 hp.  That motor did not last long and after doing the calculations, I replaced it with a 5 hp industrial compressor motor.  It now starts quicker and runs smoother.  And it still works after more than 10 years of my use.

Bigwolf