Add 240 outlet to sub-panel (pics)

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  #1  
Old 11-15-05, 07:12 AM
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Add 240 outlet to sub-panel (pics)

I have a sub-panel that is fed from the main at the house. Can I add a 240v outlet on this panel? The main panel is feeding one line to the subpanel off a 60amp breaker.

Breaker


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  #2  
Old 11-15-05, 07:38 AM
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If the 240V circuit you want to install is 60A or less, you can add it to this subpanel.

It looks like your subpanel is missing a couple things though. First, there is no main disconnect. Since this is a detached structure, the panel is required to have a main disconnect. Second, I see no bare conductor heading out to a ground rod which is also required for a detached structure. It could be that I just can't see this one on the right-hand side of the picture. Was this subpanel inspected after installation?
 
  #3  
Old 11-15-05, 10:45 AM
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Good eyes! Nope, no main disconnect. And it has a ground wire coming up from the ground (outside) but does not connect to the ground coming from the panel. For that, I will just connect the two.

The shed was built in '98 and never had a final inspection - how nice. We just bought the house. How hard is it to add a main disconnect?

Outside of these issues, I would need:
1 240v outlet (20amp)
1 20amp breaker (2 pole)
10-3 wire to connect the breaker and outlet

Would this be correct?
 
  #4  
Old 11-15-05, 11:24 AM
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If there are six breakers or fewer, then they collectively serve as the main disconnect, and you need no other. If there are more than six breakers, then you can backfeed a breaker for the main disconnect (by connecting the incoming supply to the breaker terminals).
 
  #5  
Old 11-15-05, 11:41 AM
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Originally Posted by jmartin104
1 240v outlet (20amp)
1 20amp breaker (2 pole)
10-3 wire to connect the breaker and outlet
Do you need a pure 240V 20A receptacle or a 120/240V 20A receptacle? The distinguishing factor will be 3 prongs or 4. If it is a pure 240V receptacle, then you only need 12/2 cable, not 12/3 cable. Unless you are running a substantial distance, you only need #12 wire not #10.

Good catch John regarding the main disconnect. You would only need a main disconnect if the breaker box was filled up.

Some inspectors require the disconnect on any panel that is capable of holding more than 6 breakers and some will only require the disconnect when the panel actually has more than 6 breakers; apparently yours was the latter.
 
  #6  
Old 11-15-05, 11:49 AM
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My compressor has 3 prongs but two go in the opposite directions. As in:

- |
o
 
  #7  
Old 11-15-05, 01:09 PM
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It sounds like you are describing a 6-20P plug, which is a 250V 20A. If that is the case, you can run this circuit with 12/2 wire because the compressor need two hots and does not need a neutral wire. Simply color the last few inches of the white wire with a red or black sharpie marker to designate that wire as a hot.

Check this plug chart to be sure:
http://www.leviton.com/sections/techsupp/nema.htm
 
  #8  
Old 11-15-05, 04:57 PM
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Hmmmm. I've been told a 12/2 and 10/3. The 12 and 10 are just wire guage but the 3 and 2 concern me. I'd hate to wire this thing incorrectly. What's the main difference?
 
  #9  
Old 11-15-05, 06:57 PM
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Two or three insulated conductors. You only need two. If you are installing the outlet near the panel, you can use 12/2.
 
  #10  
Old 11-16-05, 09:03 AM
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Originally Posted by ibpooks
It sounds like you are describing a 6-20P plug, which is a 250V 20A. If that is the case, you can run this circuit with 12/2 wire because the compressor need two hots and does not need a neutral wire. Simply color the last few inches of the white wire with a red or black sharpie marker to designate that wire as a hot.

Check this plug chart to be sure:
http://www.leviton.com/sections/techsupp/nema.htm
Do I connect them to the same post? Or do I do it like in the picture: white on top, black on bottom? My compressor is a 240v/15amp if that makes a difference.
 
  #11  
Old 11-16-05, 09:06 AM
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White on top and black on bottom, or vice versa. Doesn't matter.
 
  #12  
Old 11-16-05, 05:54 PM
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ok, I have the outlet wired and going to wire the breaker. What's the main difference between a 2 pole (the one I'm using) and a single pole? What goes on the second bolt at the bottom? I have one on the top and two on the bottom. Black on bottom, white on top.
 
  #13  
Old 11-16-05, 06:50 PM
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I don't understand your post. And that makes me worry that you don't understand what you're doing.

What is a "second bolt at the bottom"?

You said that you have "one on the top and two on the bottom". One what and two what on the top of what and the bottom of what?
 
  #14  
Old 11-16-05, 07:32 PM
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Perhaps I'm a bit unclear. I have a 2 pole breaker. The breaker has a screw/bolt (lugs) where the wires attach. There are two on the bottom and one on the top.

I'm using 12/2 wiring. So, white on the top with the single lug and one black on the bottom with the double lug. I'm trying to figure out what the second lug is for.
 
  #15  
Old 11-16-05, 07:48 PM
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Please give us the make and model number of the breaker.
 
  #16  
Old 11-17-05, 05:22 AM
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Just to recap: I want to install an outlet for a 240v air compressor that will be fed off an existing sub-panel. Here are all the pics of the parts involved:

Compressor Tank

Compressor Motor

Compressor Plug

Breaker Panel Cover

Inside Breaker Panel

2 Pole Breaker

12/2 wire
240 outlet/cover
 
  #17  
Old 11-17-05, 06:41 AM
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You first need to re-identify the white wire to black or red.
Then connect that wire to the other terminal on the recepticle and the breaker, just like the real black is.
 
  #18  
Old 11-17-05, 07:05 AM
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Originally Posted by classicsat
You first need to re-identify the white wire to black or red.
Then connect that wire to the other terminal on the recepticle and the breaker, just like the real black is.
Can you explain a bit more.
 
  #19  
Old 11-17-05, 08:11 AM
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The breaker has a screw/bolt (lugs) where the wires attach. There are two on the bottom and one on the top.
In the picture you provided of the breaker, I see only two connection points, not three. So I remain confused. But those two screws are where your black and white wires go.

"Reidentify" is just a fancy word for taking a black magic marker and coloring the last inch of the white insulation black so that it provides a visual clue to the next person that comes along that this is not a neutral wire.

It would still be useful to know the breaker model number, which I cannot read from the picture. but should be printed on the breaker somewhere.
 
  #20  
Old 11-17-05, 08:13 AM
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Use a red or black permantent marker to color the last few inches of the newly installed white wire inside the panel box and at the receptacle box. When you look at the cable you installed it should have a black wire, a bare ground wire, and a white wire colored in black or red. This is to prevent a major problem in the future where someone could mistake a 240V circuit for a 120V circuit.

In the breaker box:

The breaker has two lugs on it: connect the black wire to one of the lugs and the white wire (marked black or red) to the other lug of the breaker.

You should connect nothing to the bus bar where the existing white wires terminate.

Connect the bare ground wire to the grounding bar in the bottom right corner of the panel.

At the receptacle:

Connect the bare ground wire to the green colored screw on the receptacle.

Connect the black and the white (marked red or black) to the other two terminals on the receptacle. It doesn't matter which wire goes to which screw.
 
  #21  
Old 11-17-05, 08:21 AM
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Thanks John! I just got all of that from my electrical book just now - forgot I had the damn thing. I think an earlier post confused me on putting the white on top on the bus bar.

The model is: AB-5226 I believe.

ibpooks - Perfect! Exactly as I have it setup, minus the breaker which is now clear as I don't use the bus bar.

Thanks all! I'll post my results shortly.
 
  #22  
Old 11-17-05, 11:15 AM
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The job is done and the compressor works just fine. Thanks to everyone!
 
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