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running sub panel for welder,air compressor and plasma cutter

running sub panel for welder,air compressor and plasma cutter

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  #1  
Old 02-09-13, 02:20 PM
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running sub panel for welder,air compressor and plasma cutter

I have a detached garage about 60 foot from my house that I am looking to wire for a plasma cutter and welder. I have 200amp service at my house, I already have a compressor thats been hooked up for a few years now its on a 220 20amp box. I think I should go with a sub panel now since adding the cutter and welder. I do not currently have any empty connections in my electrical panel, but do have 1 running to the garage for lights and a 2 pole running for the compressor. Should I ditch the lines running for the lights and compressor, add them in at the sub panel?

heres a link for the plasma cutter and welder

MIG175 and Versa Cut Plasma Cutter Kit

welder specs are input: 210-240 VAC; 50-60Hz; 22AMP
plasma, what I can find is Electrical Input:110 VAC or 220 VAC, Amperage Output Range: 14-40 Amps,Output Voltage: 96 V

I wont be running all 3 at once of course, but the compressor will be refilling while using the plasma cutter. What gauge wire to the sub panel and is a 50 amp sufficient? Anything else I missed?

thanks
 
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  #2  
Old 02-09-13, 03:44 PM
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The 240 volt line to the detached garage will have to be abandoned if you run a subpanel so that will give you space. Did you have a separate 120 volt line to the garage in addition to the 240 volt line. If so the 240 volt line should never have been run. So when you abandon those two circuits you will actually have a space left over in your panel.

A 60 amp service may be enough but till we know the input not output amperage of the plasma torch we can't say for sure. 60 amp service would require three #6 and a #10 THWN if run in conduit.
 
  #3  
Old 02-09-13, 04:16 PM
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Yes, it has both a 120 and a 240, both will be removed if I add a sub panel, but you are saying remove both any ways in favor of a sub panel as the garage shouldn't have both line's ran to it, I will correct that.

I will also try and find more info on the requirements of the cutter. Thanks for your help so far.

Edit, found this on it Electrical Requirements: --220 Volts AC; 30 Amp; Single Phase --110 Volts AC; 20 Amp; Single Phase
 
  #4  
Old 02-09-13, 04:51 PM
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Yes, it has both a 120 and a 240, both will be removed if I add a sub panel, but you are saying remove both any ways in favor of a sub panel as the garage shouldn't have both line's ran to it
Yes, it is not code compliant. You can have only one power source to a detached structure.

220 Volts AC; 30 Amp; Single Phase --110 Volts AC; 20 Amp; Single Phase
Then a 60 amp service should be adequate. Suggest you buy a 12 space 100 amp main breaker panel as your sub panel. You will need to buy a ground bar to add to it and you will need an eight foot ground rod. Conduit needs to be buried at least 18". You could go direct burial cable but if you go with at least 1" PVC conduit you have an easy upgrade path if you need to increase the supply in the future.
 
  #5  
Old 02-09-13, 06:16 PM
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Thank you again for your reply. I will do as you have said but for my own knowledge, why could I not utilize the existing ground at my main source? I want it done properly so will add the ground, just curious.
 
  #6  
Old 02-09-13, 06:36 PM
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The ground rod you add is at the subpanel. From your supply you will run an EGC (Equipment Grounding Conductor) using #10. The EGC and a #6 wire from the ground rod at the subpanel will go to the bonded ground bar you add to the subpanel. In addition all branch circuit grounds will go to the ground bar in the subpanel. All your neutrals will go to the isolated neutral bar that comes with the subpanel. You will not use the bonding screw and/or strap for the subpanel neutral.

Note: Assuming the main panel at your house is the first panel after your meter it will be wired a bit different. The grounds and neutrals will be mixed together. That is only done at the first panel after the meter. All sub panels are wired with bonded groubd bars and separate isolated neutral bars.
 
  #7  
Old 02-10-13, 05:46 AM
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Alright, I got it now...one last question if you don't mind, any reason to use wires instead of a cable? Found this cable, seems like what I need?

UFB 6/3 - Underground 6 3 Copper Electrical Wire And Cable Products
 
  #8  
Old 02-10-13, 06:01 AM
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You can use UF-B cable instead of conduit if you want. conduit allows upgrades or replacements in the future without digging.

While code-compliant, you don't want to try to pull 6/3 through conduit, it will be a pain in the ....

If you use cable, you'll sleeve it in PVC conduit where it comes out of the ground.
 
  #9  
Old 02-10-13, 06:52 AM
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Thanks for the reply Zorfdt, I figured it would be okk but just wanted clarification. I also found this illustration on diy, looks exactly how it was explained by ray2047.
 
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  #10  
Old 02-15-13, 01:21 PM
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Was getting ready to hook up the 6/3 ub cable I got and not sure if I miss measured or they miss cut ...either way cable is about 2 foot short from reaching the panel at the house. Any way to extend the cable?

Thanks
 
  #11  
Old 02-15-13, 03:31 PM
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They make under ground splice kits but is there any way you can put a junction box above ground. Say at the point where you come up either at the house or garage.
 
  #12  
Old 02-15-13, 03:45 PM
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Yes, what I have done is ran it from garage to house. If possible I would rather fix the house end as the cable is already through the wall into the conduit then buried to the house. I think what happened when I measured is I didnt allow for the 2 foot extra at each end for the depth...or they screwed me out of some, cant tell now. What I have at the house end currently is just the cable coming out the ground, not in conduit just the cable itself.

Picture did not come out so well as its getting dark but if you look you can see whats going on.

thanks
 
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  #13  
Old 02-15-13, 05:51 PM
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What I have at the house end currently is just the cable coming out the ground, not in conduit just the cable itself.
I think you could install a NEMA 3R (raintight) junction box under the panel so you can splice the extra length you need in the junction box. I would use conduit to protect the cable where it comes out of the earth to the box and another piece of conduit beween the junction box and the panel. If you come out the top of a 3R box, use a threaded hub in the top of the junction box to keep it weatherproof. These are generically called Myers Hubs.
 
  #14  
Old 02-15-13, 07:22 PM
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Ok, I will see what I can find. I just dont know if I will find one with big enough openings for this size cable. I will look at lowes, home depot etc. tomorrow.

Thanks for the help.
 
  #15  
Old 02-16-13, 06:28 AM
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I'd rather have a box with no knockouts and cut my own at the size I want.
 
  #16  
Old 02-16-13, 07:27 AM
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You can get PVC boxes with no holes. If you use a PVC box you can easily drill the holes with a hole saw.
 
  #17  
Old 02-16-13, 12:06 PM
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OK, Thats what I will do then. Whats the best way to splice the wires together? I wouldnt think just wing nuts taped but?
 
  #18  
Old 02-16-13, 12:45 PM
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Wire nuts no tape if you want it to look professional. The big blue ones. Even better but more expensive Polaris wire connectors.
 
  #19  
Old 02-18-13, 05:25 PM
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Forgot the wire nuts somehow when I went to the hardware store, will have to go get some tomorrow so I can finish up. What I am doing so far I believe is correct but wanted you all's input to be sure.

This is the panel I will use in the garage, and how the wires should connect if I understood correctly? The brownish wire is bare copper. I do have a grounding rod and a section of #6 to run to it, that goes from the equipment ground outside to the ground rod I believe?

The other picture is now what I have coming out the ground at the house end where I will use the wire nuts to make the connection into the main panel. The junction bux is about 2 foot from the main, is it ok to remove the sheathing from the cable running from the junction box to the main? Like I said, its about 2 foot and will be in conduit coming from the junction box.
 
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  #20  
Old 02-18-13, 06:10 PM
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There seems to be two neutral bars and no ground bar. Did you buy a ground bar for the panel? The green screw on the left hand neutral bar needs to be removed. You definitly don't connect the ground there. The two holes about a half inch from the bottom of the picture are probably for the ground bar.
 
  #21  
Old 02-18-13, 06:28 PM
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No, I did not buy a ground bar. I thought this panel had what I needed according to the supply house I got it from. I will get a ground bar tomorrow then. I assumed the left was where the ground went because it says "equipment ground only this side", also labeled bond screw, assume thats the green screw then labeled ground strap. The right side is labeled bond screw and neutral strap.

If I install the ground bar, is that also where I would run the green wire for the grounding rod?

The picture I posted in post #9, that is not correct then?

thanks for your continued patience and help.
 
  #22  
Old 02-18-13, 07:03 PM
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It doesn't matter how you do it but, in a subpanel, all grounds must be bonded together and to the enclosure. That means the ground from your main panel, the ground from your ground rod, the branch circuit grounds and the box, all together.

The neutrals must be isolated from ground. They are all connected together and share a bus, but they are isolated from everything in the list above, including the box. The bus must be isolated.
 
  #23  
Old 02-18-13, 07:26 PM
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bond screw, assume thats the green screw then labeled ground strap. The right side is labeled bond screw and neutral strap.
As Nash wrote, in addition to the green screw the bond straps must be removed.
 
  #24  
Old 02-18-13, 07:33 PM
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OK, well I am just confused then. I thought I was on the right track but thankfully finding out ahead of time I was wrong. Maybe I will just hire an electrician to do it when I get the money. I have wired my 220 compressor, lights in the shot etc., but for some reason just having an issue figuring out what goes where here.
 
  #25  
Old 02-18-13, 07:38 PM
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You are on the downhill side. You really don't need an electrician. Sleep on it and then explaing what confuses you and we will explain it another way.
 
  #26  
Old 02-18-13, 07:52 PM
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for some reason just having an issue figuring out what goes where here.
It shouldn't be hard to do and, as Ray said, we can help you with it.

You may be able to run all of your grounds to the left-hand bar and bond the can with the green bond screw. The question will be whether the bar on the right is isolated, or can be isolated. Test for continuity between that bar and the bar on the left, and between that bar and the can, with and without the bond screw in.
 
  #27  
Old 02-18-13, 08:13 PM
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In another thread one of the mods said code doesn't allow a neutral to be purposed as a ground but I can't provide a cite.

Here is another way:

 
  #28  
Old 02-18-13, 08:35 PM
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OK, I think whats throwing me is I dont see where the neutral and ground are connected if thats whats being said to be the case? either way, installing a ground bar fixes that issue correct? I will take a better look tomorrow when I can see better...someone really should run some electric to the garage so I can see in the dark

Also, is it ok to remove the sheathing from the cable going from the junction box to the main? Its about 2 foot and will be in the conduit. When I was test fitting everything its pretty tight working with the cable in the junction box and leading into the main, would be much easier handling wires instead of the cable.

thanks again
 
  #29  
Old 02-19-13, 09:23 AM
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I think whats throwing me is I dont see where the neutral and ground are connected if thats whats being said to be the case? either way, installing a ground bar fixes that issue correct?
Not necessarily. As I said earlier,
Originally Posted by Nashkat1
in a subpanel, all grounds must be bonded together and to the enclosure. That means the ground from your main panel, the ground from your ground rod, the branch circuit grounds and the box, all together.

The neutrals must be isolated from ground. They are all connected together and share a bus, but they are isolated from everything in the list above, including the box. The bus must be isolated.
To do that,
Originally Posted by Nashkat1
You may be able to run all of your grounds to the left-hand [bus] bar and bond the can [to that bar] with the green bond screw. The question will be whether the bar on the right is isolated, or can be isolated. Test for continuity between [the bar on the right] and the bar on the left, and between [the bar on the right] and the can, with and without the bond screw in [to see whether the bar on the right is isolated or bonded].
If that bar is not isolated, and cannot be isolated by removing a jumper as Ray suggested. then you'll need to buy and install an isolated bus bar for the neutrals instead.

Also, is it ok to remove the sheathing from the cable going from the junction box to the main? Its about 2 foot and will be in the conduit.
The individual conductors found in assembled cables are not rated for use outside the cable. That said, it will be easier to pull individual conductors through that short piece of conduit and work with those. The big box stores sell THHN/THWN by the foot. Your neighborhood hardware store might too.
 
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Old 02-19-13, 10:30 AM
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If that bar is not isolated, and cannot be isolated by removing a jumper as Ray suggested. then you'll need to buy and install an isolated bus bar for the neutrals instead.
IMHO easier to just install a ground bar instead of looking for an isolated neutral bar that may be hard to find.

OK, I think whats throwing me is I dont see where the neutral and ground are connected if thats whats being said to be the case?
Neutral and ground are never connected in a subpanel. The ground bar is bonded (connected) to the metal case. The neutral bar(s) are not bonded (connected) to the metal case. In your picture you can see the black insulating material the neutral bars set on so they don't connect to the case.

Most panels you buy though are not sold as subpanels. They are sold as a main panel. In the main panel and only in the main panel the grounds and neural are connected so when it is used as a subpanel you must add a ground bar and isolate the neutral. When used as a main panel the neutral bar(s) are bonded using a green screw as seen on the left neutral bar in your picture and possibly a metal strap.
 
  #31  
Old 02-19-13, 10:47 AM
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Ok, so remove the green screw, for incoming from the main I would add the isolated ground and run my ground bar from it as well as the bare ground coming from the main, and use the neutral thats provided.

Outgoing neutrals would go to the exsisting neutral bar, all grounds would go to the new isolated bar I add, and hots of course to the breakers.

Right?

I will have to buy new wire again for the connection from the junction to the main as I pulled it froms its jacket already.
 
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Old 02-19-13, 11:32 AM
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Yes, you have it except:
all grounds would go to the new isolated bar I add,
The ground bar is not isolated it is bonded (connected) to the metal box because it is connected directly to the metal of the box by being bare metal that touches the metal case.

Sometimes there are multiple ways to do the same thing. I think I may have confused you a bit because my way differs from Nash's but both are correct and accomplish the same thing.
 
  #33  
Old 02-19-13, 11:40 AM
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I got it now, not sure why that was so difficult for me to grasp, simple now that I understand it. Of course its raining today so I cant do much with it but will get it finished up hopefully tomorrow.

Thanks for the continued support..I know sometimes when someone isnt following it can get frustrating easily. Thanks, to you both.
 
  #34  
Old 02-19-13, 11:52 AM
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Excellent! Let us know how it works out.

One more thing. The two neutral bars may have only been connected by the bonding strap(s) and screw to the case you are removing. If that is the case run an insulated white #6 wire between the two neutral bars.
 
  #35  
Old 02-19-13, 01:55 PM
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Thanks for the continued support..I know sometimes when someone isnt following it can get frustrating easily.
Thank you for recognizing that, and for continuing to dog for what you need. When someone says,
I got it now,
that's a reward.
 
  #36  
Old 02-21-13, 04:17 PM
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Ok, I went to the electric supply today to get a few feet of the wire I needed. While waiting at the counter I talked to an electrician and he said that all I need to do is remove the green bonding screw then run grounds to it, neutrals to neutral and of course hots to hot. I am still planning on hooking everything up as shown here but curious as how his way can be "right" as well, should only be one right way, no?

thanks again guys..
 
  #37  
Old 02-21-13, 04:55 PM
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I talked to an electrician and he said that all I need to do is remove the green bonding screw then run grounds to it, neutrals to neutral and of course hots to hot. I am still planning on hooking everything up as shown here but curious as how his way can be "right" as well, should only be one right way, no?
There is often more than one way to skin the cat. I don't fully understand what he was advising, or how it differs from what we've said here, so I don't know if he was describing something that would work or not.

If he was saying, for example, that you could remove a bonding strap that connected the two installed bus bars and then use one for neutral (isolated) and the other for ground (bonded, presumably with the green screw), then that's something Ray suggested earlier.

How are you planning to do it now? So long as all the grounds are bonded together and to the panel box, and the neutrals are together and isolated from the grounds and the box, it should be fine.
 
  #38  
Old 02-21-13, 06:46 PM
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If you look at post 19, the image, he was saying to wire it like that only remove the green screw and run my grounds to it and the grounding rod off of that.

I think I will do as was said by installing a new ground bar and go from it. I at least know thats what you guys suggested and would be safe.

I
 
  #39  
Old 02-21-13, 11:40 PM
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OK, that's good. There's one thing wrong with his suggestion and possibly two more.

The one thing wrong is that the subpanel enclosure - the can - must be bonded to ground. In his suggestion, removing the green screw would break that bond.

Two, his suggestion will only work if the two buses aren't tied together.

Three, some installers have been denied final approval because they modified the panel in an unauthorized manner. Installing an additional ground bar avoids that.
 
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Old 02-22-13, 04:07 AM
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Basically I could think of a way to do it with just the included bus bars but it would not be as suggested and while it might be electrically okay it could raise red flags with an inspector. The inspector expects to see a ground bar. If he sees the ground bar you are likely to pass. If he sees ground wires to what the manufacturer obviously intended as neutral bars you are going to fail. Ditto what Nash said in other words. Install the ground bar and use the neutral bars as neutral bars.
 
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