The Alchemist

iTrader: (19)

Well, I scored the deal of the century and picked up a used, 60 gallon two stage craftsman compressor for $200. The problem I'm having right now is wiring.

The compressor came with a cord and plug installed from Craftsman that has a 220/20amp plug on it. Looking at the plug, you have a ground prong on the bottom, and one of the top prongs is vertical and the other is horizontal. That's not a problem as I was able to find the matching outlet at Home Depot. My problem is the 220 line that I have already run in the basement. It was originally run to the stove when we moved in, but we had a gas range put in, and no longer used the line. I capped the line, turned off the power to it, and coiled it back at the box for 'future use'.

The issue is the line itself. It is a 8/2 wire with a black hot, black w/red stripe hot, and a bare ground. All of the wires though appear to be silver strand, and not a single copper like normally you'd find with 12/2 or 14/2.

The stranded wire is way to big to be attatching to the outlet that I got, so what's the best way to wire this up? Should I change the plug on the compressor and then use a beefier outlet similar to what's used for a dryer?

I'll be calling my brother-in-law later today as he's a master electrician and ownes his own commercial electric business, but I'm just curious what route is best to go.

Thanks.

The Alchemist

iTrader: (19)

I figured it out..... got some advice, returned what I didn't need, I'm good to go.

Turned on the compressor and let it fill to 110psi to see how well it holds pressure. Got up this morning and it's still at 110psi.

My hope is that with it in the basement, I can just leave it turned on, and that it won't bleed down and kick on when not in use.

I'll post some pics and specs later.

Camaroholic

iTrader: (1)

I leave my compressor on all the time, have had no problems. It's been a long time since I turned it off, actually.

My 'system' is copper except for the 3' hose that goes from the tank to the wall. I have ball valves at each drop that I shut off when I leave the shop... the hoses & (very used) fittings do leak air, but the rest of the system does not. I don't notice any pressure drop unless I forget to close the ball valve leading to a hose.

So, as long as you're not leaving a hose / air fitting under presssure, you shouldn't see any significant leakdown.

The Alchemist

iTrader: (19)

Well, talking with some friends, I decided to put a non fusable switch in the garage so I'll be able to turn off the compessor when not in use and I won't have to run downstairs to turn it on or off. It'll only add 6-8 feet of extra wire, which I have plenty of.

00cls1camaross

iTrader: (10)

So what did you end up doing for the wiring issue? did you change the wiring to 12/2? Did you change the breaker to a 20 amp 2 pole?

The Alchemist

iTrader: (19)

I left the wiring alone and used wire terminal lugs to connect them to the pressure switch on the compressor.

I ran the wire into the garage into a terminal box, similar to what's used on an outside a/c unit, and then ran the wire back into the basement and directly to the compressor.

I think I may put a 220 outlet in the garage for future use since it's a 40amp circuit, and the wire is 8-gauge which will support 40+ amps as well, and the compressor only uses 20 amps on startup, so that leaves plenty of capacity for other things.

00cls1camaross

iTrader: (10)

Your not suppose to do those sorts of things. It is called "double lugging" when you pull multiple circuits off of a dedicated circuit. In New Mexico and Arizona, state inspectors don't allow that. Just letting you know not trying to be rude.

I have seen a house burn down from that, for some reason if the electical load was too much for the circuit and the breaker was faulty. You could start a fire. It is possible but not likely. I'm just trying to help....

Another thing...

Your Compressor is 20 amps, therefore, it needs a 20 amp circuit.

At the very least you need to put a 2 pole 20 amp breaker in place of the 40 amp breaker to make sure you compressor doesnt pull more then 20 amps and fry itself.

The silver wire is actually aluminum, and it gets brittle when it is turned "on" and then turned "off". If it is always on, it will be fine. We still run main power to houses using Aluminum wire, not copper.

The Alchemist

iTrader: (19)

So having a 2 pole 40 amp breaker is a bad thing? Let me make sure my termonology is correct. The breaker is actually two breakers that are combined and it has a 40 amp rating.

I haven't actually put another line off the breaker yet, and I will confirm everything is safe and legal with my brother in law who owns his own commercial electrical contracting business that does big commercial jobs. I'll get his blessing because the last thing I want to do is cause an unsafe situation in our house.

So since you're saying that the line is meant to stay hot all the time, and not be switched, can I run it to the box in the garage, then use copper line to go to the compressor, since that will be the only thing that will have the power cut as I won't need to switch the main breaker anymore.

I'm guessing you have electrical experience and know the codes, so any advice is welcomed.

The Alchemist

iTrader: (19)

I was thinking about this last night and have a couple quick comments....

1. The motor on the compressor has an overload circuit, so if it pulls too many amps it will trip.
2. If I were to replace the 40amp double pole with a 20amp, it would probably pop everytime the compressor kicked on since it has a 20amp startup load.

I agree with not double lugging the circuit, it was just a 'what if' type thought.

00cls1camaross

iTrader: (10)

The 2 pole, is why it looks like two breakers. It has two poles and it pulls 120 volts off of each bus in your panel making 240 volts. The 40 amp rating is how many amps the breaker allows before it will 'trip' and go into the middle. You only want to feed the compressor what it needs. Though it does have the overload switch, putting the proper breaker in is another control we use to make sure if something fails, there is another control to maintain.


I promise you that running another line off of the dedicated circuit is something your not suppose to do.

When you put disconnect boxes and terminate aluminum wiring, you need to by a special gel for the wires. This special gel doesn't let the aluminum wire (where it is terminted) get too hot and make a proper connection.

00cls1camaross

iTrader: (10)

Either way, you should only feed the compressor the necessary power it needs. You should have a manual that tells you how much amps you pull, from what you said, it pulls 20 amps at startup. Breakers are designed to allow an initial over-draw of amps as the motor turns on, and then once the amps steady below 20, the breaker will trip if it goes over.

It is kind of hard for me to give you advice without be being there and drawing you something. If i were you, I would talk to a residential electrician. I don't work on commecial, but i can take car of most jobs. Just like you know someone who works on commercial can get residential done. Would you take your T/A to midas to get a cam swap? or would you take it to texas speed.... If you see my point

The Alchemist

iTrader: (19)

I see your point completely. I trust my bro-in-law. He not only ownes his own company, he's an electrical engineer and master electrician, and I trust him completely. I haven't actually wired anything yet. I have the 220 line coiled under the panel and the breaker turned off at this point. It's been that way since we moved in and replaced the electric stove with a gas stove. My bro in law was the one who reccomended running it into the garage for future use.

fast98

iTrader: (16)

If your house has a 200 amp service, I would look at running a 100 amp circuit from that box and put a seperate box in the garage. You can then run a 12/3 down to the basement for the compressor off of a 20-30 amp circuit. This way you will have extra circuits in the garage, comes in handy if you need 220 for different things all at once.

The Alchemist

iTrader: (19)

Well, my buddy came over Saturday and we got it wired and done. I ran the 8-stranded wire to the garage and terminated at a 50amp/250v outlet. The we ran 12/2 wire with a plug down to the compressor.

It's up to code, legal, and safe. Thanks for everyones help.