Ford Mustang Forums banner

1 - 20 of 26 Posts

·
Registered
Joined
·
420 Posts
Discussion Starter #1
When my house was built I had an extra 220v outlet wired into my garage, so that one day when I could afford a compressor I would only need a plug. Well, the day has come for me to order the compressor (8 years later).

However, now that I'm reading it seems they're all hooked up by three wires. My outlet is 4 prong; what gives?

The outlet is wired up to a 40amp breaker, which is what the compressor manufacturer recommends. The mfr also specifies 230v, but from what I've read here in the US a connection rated at 220 is the same as 230 or 240. So my existing outlet should suffice, right? As long as I get the pigtail issue sorted.
 

·
Registered
Joined
·
6,262 Posts
Connect that wire to that thing,
that wire to that thing,
that wire to that thing,
that wire to that thing,
that wire to that thing.



And, that thing on your car, use that thing over there.

Got that? :)


What outlet type do you have, and what plug type do you have?
Got a cell phone that takes pictures? ;)

 

·
Registered
Joined
·
270 Posts
Take a picture of your plugin in the garage and a picture of the air compressor plugin.
Proceed to Lowes or Home Depot where you while find an adapter for about 15 bucks.
 

·
Registered
Joined
·
6,262 Posts
Looks like a 14-50R... picture uploaded sideways.
The compressor hasn't delivered yet but I've read it has a three wire hookup. I need either an adapter (3 to 4 prong) or swap in a 3 prong receptacle, right?
Imho, what ever you do, leave the existing outlet alone. It's better and more versatile as it is now verses changing it over.

I suggest that you either replace the plug on the compressor, or make your own adapter.

Fwiw, on the adapter cable, going from a higher-amperage outlet to a lower amperage female receptacle is fine. That's what I do for my 220V electric heater that I use in basements. I connect it up to the higher electric Dryer outlet. Make sure you use heavy gauge wire for any adapter.

(The following was edited to fix a typo)
Some pictures:
Wiring of the outlet. To adapt to a 3-wire 220v device, you would not use the "Neutral" connection.

Also: https://www.google.com/search?q=3+wire+220v

Some plugs that would be good for the end of your compressor:
[ame]http://www.amazon.com/Camco-55255-PowerGrip-Replacement-Plug/dp/B000PGVZ30/[/ame]
Camco 55255 50 AMP PowerGrip Replacement Plug
Price: $14.46



[ame]http://www.amazon.com/Pass-Seymour-3867CC5-125-volt-250-volt/dp/B000BQW4OS[/ame]
Pass & Seymour 3867CC5 Angle Plug Three Pole Four Wire 30-Amp/50-Amp 125-volt/250-volt
Price: $16.34


Good Luck!
 

·
Registered
Joined
·
420 Posts
Discussion Starter #8
So I could just grab a 14-50 pigtail and just leave the ground wire disconnected at the compressor? That seems easiest/least expensive. I believe the compressor is being shipped without any wiring from the factory.
 

·
Registered
Joined
·
10,272 Posts
So I could just grab a 14-50 pigtail and just leave the ground wire disconnected at the compressor? That seems easiest/least expensive. I believe the compressor is being shipped without any wiring from the factory.

The compressor isn't coming with a cord?
 

·
Registered
Joined
·
420 Posts
Discussion Starter #10
The compressor isn't coming with a cord?
I don't believe so... it's a Chicago Pneumatic RCP-561VNS.
From my understanding it comes with the motor wired to the pressure switch but the consumer's responsible for wiring it up from there.

It's a fairly hefty unit, but I wanted to err on the side of overkill vs. not having enough compressor for more lofty projects down the road.
 

·
Registered
Joined
·
141 Posts
Bingo.

Just did this last weekend for my brother and his Husky single phase 220 60 gal compressor. I ran the dual pole breaker and installed the outlet though, si I kept it easy with a three prong.

Your compressor, if single stage, like many are, will probably only have 3 connections for the motor.

Gilroy, correct me if I'm wrong here, but it should be (or at least the Husky 60) black wire for power, white wire for power (but hot, not a return) and a ground.

How you wire the black and white determines which way the motor spins.

Not sure if that matters on your particular model or not.
 

·
Registered
Joined
·
10,272 Posts
It is if you use a 10/2
10/2 is black, white and green ground.

What I'd do is get a 10/3 SO cord which will have black, red, white and green.

Black and red will be your two hots, white will be your neutral and green will be your ground.
 

·
Registered
Joined
·
4,962 Posts
You can use the socket in the garage just fine, and legally. Buy a mating plug and do not use the neutral. The neutral is the middle straight pin.

That type of socket supplies 120/240 (there hasn't been 220 in the USA since the 1950's). It 240 from outside flat pin to outside flat pin.

From either outside to the center flat pin is 120. Just leave that blank.

The green safety ground goes to the round pin. Either of the 240's can swap. Doesn't matter.

Make sure the breaker is downsized to the rating for the compressor.
 

·
Registered
Joined
·
4,962 Posts
So I could just grab a 14-50 pigtail and just leave the ground wire disconnected at the compressor? That seems easiest/least expensive. I believe the compressor is being shipped without any wiring from the factory.
NO. NO. Never get electrical advice in a car forum. :)

You leave the NEUTRAL float.

You take EITHER of the 240 to the outside flats, doesn't really matter which goes to which as long as the 240 goes to outside pins.

The GROUND (round pin) goes to the compressor ground. That has to be a green or bare wire. It is the safety ground. It can never be used for current.

The center flat pin is for 120 use. Either do not load it in the plug, or leave it blank. It is for 120/240 applications like clothes driers.

You should downsize the breaker to what the compressor calls for, or you can mount a properly sized breaker in a box and plug it into the outlet socket. That is OK for codes because the jurisdiction of the code stops at the outlet, but for your own safety you should do the plug in breaker box safely. It would be better to downsize the panel breaker, if it is too large.

What breaker does your compressor call for?? What breaker is in your service panel?
 

·
Registered
Joined
·
420 Posts
Discussion Starter #17
The compressor calls for a 40amp breaker, which happens to be what my outlet is connected to.

If I grab a 4 wire pigtail and connect the two hots + ground to the pressure switch, what do I do with th neutral wire? Would it be best to cut the prong off on the plug end so it's not connected at all?
 

·
Registered
Joined
·
4,962 Posts
No

If there is no neutral to connect to on the compressor just put the neutral and ground together.
That is completely against electrical codes, because it is a system and human hazard.

Tying a neutral and ground together outside of the main panel can interfere with operation of things like GFIC breakers, and should the power mains develop an open neutral in the main panel, the frame of the compressor could go to as much as 120V to earth.

The neutral of any 240 line is never allowed to contact exposed metal, or be used as a ground, or be connected to the safety ground anywhere except the main panel. That is the only allowed common point.

The Neutral, the center flat pin, has to FLOAT if 120V is not being used. It is never allowed to contact any exposed metal, or to be used as a cabinet or frame ground.

The *****ONLY***** thing allowed to connect to the frame of the compressor is the safety ground, which is the round pin.

The proper way for him to connect this is either 240 lead to the outer flat pins, the frame of the compressor to the round pin, and the center flat pin is either not installed or just left floating.
 
1 - 20 of 26 Posts
Top