Air Comp Electrical Question

[lts1ow]

Picked up an old air compressor from my grandfather's house and wanna try to wire it up above my garage. It currently has a dryer 220v plug spliced to it, but would rather hardwire it and knife switch it.

Can anyone confirm that this is 220v and maybe offer insight on what breaker I should run? The dual voltage is confusing me, the weekend and all. :roflmao:

 

[CentolaCCSB]

Yes you can change the voltage to the motor depending on what taps you use. Should be a diagram to show what taps to use for each voltage. So with that if you supply 240 volts that motor will draw 12 amps, with motors you need to apply a demand factor of 125% of FLA full load amperage so you will be good with a 15 amp breaker at 240 volt

 

[lts1ow]

Ok, so 10-3 wire and a 15amp breaker, easy enough to toss in.

Should I switch to a 4 prong outlet or leave it the old 3 prong 220v?

 

[CentolaCCSB]

10/3 is overkill, you can use 14 gauge, leave the old 3 prong because at 240 volt single time phase you only need 2 hots and a ground wire

 

[CentolaCCSB]

Sorry single phase idk why i wrote single time phase

 

[lts1ow]

Alright, 14 gauge, and leave it as is plug wise.

So it gets two hots off the panel and a neutral ?

(double pole breaker too right?)

 

[CentolaCCSB]

Two hots and a ground no neutral. Im not sure what you have for plugs

 

[CentolaCCSB]

Id hard wire it and use a 2 pole switch

 

[lts1ow]

Neutral/ground is the same at the panel no?

(pardon the electrical dumb level here, I make things spin, not energize at work )

 

[CentolaCCSB]

No lol they're different even tho in the panel you put your grounds and neutrals together. ground isnt a current carrying conductor just for equipment protection

 

[c20elephant]

Would you not use 12 gauge wire and a 15 amp two pole breaker depending on length of wire.? Better yet find an UGLY's electrical reference book or find it online...

15 Amp Two-Pole Circuit Breaker at the panel if you're wiring for 220..

 

[CentolaCCSB]

Im an electrician.. On a typical reaidential home or commercial electrical panel your grounds and neutrals both terminate to the same bar. Now if you have a sub panel then you would isolate grounds and neutrals. The only reason he would have to upsize his wire is for voltage drop and I gaurentee in his house he doesnt have to worry about voltage drop because you really only have to worry about that around a 100 feet ( so ive been told) but if u want to be fancy there is a formula for voltage drop. And even then your voltage drop is so small it wouldnt make a difference

 

[c20elephant]

Im an electrician.. On a typical reaidential home or commercial electrical panel your grounds and neutrals both terminate to the same bar. Now if you have a sub panel then you would isolate grounds and neutrals. The only reason he would have to upsize his wire is for voltage drop and I gaurentee in his house he doesnt have to worry about voltage drop because you really only have to worry about that around a 100 feet ( so ive been told) but if u want to be fancy there is a formula for voltage drop. And even then your voltage drop is so small it wouldnt make a difference

You might wire with 14 gauge, I would use 12/2 and a 2 pole 15 amp breaker, you might get a trip at the breaker when the motor starts to heat up from a lot of start stop cycles using a 14 gauge wire....

 

[lts1ow]

You might wire with 14 gauge, I would use 12/2 and a 2 pole 15 amp breaker, you might get a trip at the breaker when the motor starts to heat up from a lot of start stop cycles using a 14 gauge wire....

I was a panzy and got 12-2 wire, told myself in the future I could upgrade comp motor, but really just was nervous bout 14 gauge. :rofl:

Managed to grab a single pole switch that made its way into the double pole bin so back to Lowes I go.

After its wired the tough part will be getting the comp up above the garage. Gravity and all will be a bitch.

 

[c20elephant]

How many feet of wire from the compressor to the panel..?

Edit: depending on how far your compressor is from the panel install a double pole single throw switch at the compressor as a equipment disconnect....

 

[lts1ow]

Compressor would be less than 10ft from panel, but you have to climb up into rafter area then across to it. I have a switch for it installed below so I can either kill it via breaker, or the switch from ground floor level.

 

[Drock]

Nec code book says you can only load branch circuits it 80% of its capacity. So 15amp breaker would be the bare minimum for this circuit. You would more than likely get nuisance tripping on start up.


Sent from my iPhone using Tapatalk

 

[lts1ow]

Worst case scenario I bump breaker to 20amp

 

[Budneeds2beers]

If your a electrician then you are scary.... 14/2, you crazy? Your going to burn his house down. While 15amp is the BARE minimum think about the continuous duty and continuous starting and stopping. That causes alot of heat. I wouldnt care if its a foot away from the pannel. You still have temperature rise! Thats a ten foot resistor. Wile you may not loose it in voltage drop( you will drop like one volt (that is if you have good power to begin with) so its not drop you have to worry about) and also reading that he is putting it in the rafters or elevated crawl space what is the temperature ten feet above ground in a confined space in the summer? Bet its higher then a hundred..... and you heard you dont have to worry about voltage drop till a hundred feet? Every foot homie. I think you need to take a look at uglys or mike holts website 30 amp breaker, 20 amp wire, and 20 amp switch. Look brother i know im coming off like a dick and hooking this up is small potatos but this is a persons home and i bet like alot of us he/we cant afford to just replace it do to a small mistake. Always go just a little bit bigger as you can afford, its cheap insurance.

 

[Budneeds2beers]

If you up the breaker you have to up the wire....