Two (probably dumb) questions about compressors

[Epic2112]

Question 1: I just recently bought my first house, and I want to put in a big two stage compressor. I've got an electrician coming by to do a bunch of miscellaneous work, and while he's there I want him to run a line to power the compressor. What kind of line do I need? I don't actually have a compressor yet, I figure I'll keep an eye on Craigslist for a good deal on a used one. I figure it'll have to be 220V, but I don't know the amperage since I don't actually have the compressor & specs yet. It looks like most compressors in the range I'm looking for are in the 22-25 amp range, would a 30 amp circuit do the trick or should I have a 40 amp circuit installed?

Question 2 (This is the dumber of the two): how do you guys move these things? I'll be putting mine in the basement. It's a walkout basement but you have to get there through the back yard, which is grass and hilly, I have no idea how to actually get it into place...

 

[Jim Johnstone]

I'd put in a 40 amp circuit for sure. Never know what compressor you may find.

As for moving it, can you drive around back with the compressor in a truck ?

 

[Milton Shaw]

Take it apart or you will have a lot of problems.. Motor and compressor are about half the weight of the complete unit. Its better to take time to take it off than risk it turning over because it's so top heavy.

 

[jakemac]

Question 1 : have the electrician set it up for 30amp, but run wires that can handle 50amp if it ends up being needed.

Question 2 : throw a big barbecue and invite EVERYONE you and your family knows. Drive your truck/trailer across the lawn to get close to the walkout, and pull the 'ol "can anyone give me a hand with this ?" routine to get it into the basement.
(this is what I did. Minus the barbecue, friends, or family. Basically, I moved it myself and nearly got killed )

 

[G_P]

Remove the motor and pump and you can probably roll the bare tank across the lawn and then two people can carry it into the basement and stand it upright. Then carry the motor and pump in one at a time and put it back together.

 

[md21722]

Wiring a motor circuit is different than wiring a resistive load such as a clothes drier.

The wiring depends on the HP of the unit.

You should be able to tell your electrician what the HP will be and he should be able to handle it.

To go by the NEC rules, you look at the motor nameplate for HP only. Then look at the NEC tables to determine FLC.

Wire is sized to 125% FLC.
Breaker is sized to a maximum 250% FLC.

Example: 5HP (FLC is 28A) X 125% = 35A. Use #8 Romex or #10 THHN. Breaker can be 28A X 250% = 70A although 30-40A is probably sufficient. I've even heard of people using 60A breakers on 10HP units.

 

[G_P]

Have them run wiring for a 7.5hp motor. Thats likely to be the largest single phase motor you'll encounter.

 

[sgs236]

Have them run wiring for a 7.5hp motor. Thats likely to be the largest single phase motor you'll encounter.

+1 That's good advice.

 

[Epic2112]

Take it apart

See, I knew it was a dumb question. It never even occurred to me that you can separate the motor/pump from the tank. That'll make things a lot easier. Unfortunately the property is quite hilly and full of trees so it's not really possible to get a pickup or anything back there.

I think I'm going to hold off on the wiring until I actually have the compressor, since I don't know what will be available over the next few months on craigslist.

Thanks for all the tips!

 

[Zeke]

Sounds like you need to start thinking more about future hauls to the walk out. Maybe you need a Polaris and a small flat trailer. I'm sure you will find plenty of uses for a rig like that.