Running 240v 50amp outlet in my garage

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  #1  
Old 04-14-16, 03:28 PM
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Running 240v 50amp outlet in my garage

Hey guys,

I'm getting ready to run a 240v 50amp outlet in my garage. The purpose of the outlet is to run a Lincoln AC-DC 225 welder and to also plug our camper's 50amp service in. I'll never be plugging both in at the same time, just a dual purpose outlet. The distance from the panel to the outlet location is 100'. I can't physically get the camper closer than a 50' total cord length. The camper cords are 6 gauge.

So, my question is, is 6/3 NM-B from the panel to the outlet sufficient for this application or do I need to go to 4 gauge? I want to make sure I'm getting good power at the camper with the extra 50' run. If I need to go to 4 gauge, what/where do I get it? I can't seem to find much at all for 4 gauge except for SER wire. Maybe I'm going about this all wrong and there's a better solution. I'm all ears!

Thanks,
Mark
 
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  #2  
Old 04-14-16, 04:40 PM
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Is this an attached or detached garage. 100 feet sounds like a detached garage. You can only have one circuit to a detached structure. If detached you will need to install a sub panel and abandon the existing 120 volt feed. Even if it is detached and doesn't have power you will probably want lights and 120 volt receptacles at some point so a subpanel is still a good idea.
 
  #3  
Old 04-14-16, 05:18 PM
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This is an attached garage and the garage is drywalled already. The wall I'm running down is the exterior one, not shared with the house. I can't bury the wire either because the side of the garage has a concrete walk the length of it.

The length down the side of the house from the panel to the front of the garage is 50', up/down 4' to go up and over the service door on the side of garage(I wanna follow the sill wall as much as I can for aesthetics), up 6' on side of garage overhead door, 22' across garage door, down 6' on other side = 92' + some extra for error to calculate with, I rounded up to 100'. I could knock off some feet if I kept the conduit up high(no drops/rises), I just wanted it mostly along the sill wall. I do want to run a 20 amp circuit for outlets down the same wall. Maybe I could somehow share the conduit and keep it up higher to shorten the length of needed wire.
 
  #4  
Old 04-14-16, 06:02 PM
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is 6/3 NM-B from the panel to the outlet sufficient for this application.... down the side of the house from the panel to the front of the garage is 50'
The NEC says in article 300:
Installations under ground or in concrete slabs or masonry in direct contact with the earth; in locations subject to saturation with water or other liquids, such as vehicle washing areas; and in unprotected locations exposed to weather.
It would be a decision of your local inspector if NM-b cable could be used (its dry locations only) but 6-3 cable either NM-b or UF would be difficult to run in conduit. Better to just run individual THWN wires. Then you know it will likely pass inspection and it will be easier to run.
I do want to run a 20 amp circuit for outlets down the same wall. Maybe I could somehow share the conduit
You can share but best would be to use THWN. However I'd suggest running a 90 amp feed and installing a subpanel in the garage. Simpler and gives you more flexibility for the future.
 
  #5  
Old 04-14-16, 06:45 PM
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The welder runs on 240 volts and the camper probably needs 120/240 volts. The plug on the welder is a 3 prong with two hots and one ground where the camper probably has a 4 prong plug for two hots, one neutral and one ground. Another possibility is that the camper needs 120 volts at 50 amps; one hot, one neutral and one ground. Both plugs are different. If you use 6-3 NM-B cable I believe I'd install two separate receptacles, one for the welder and one for the camper.
 
  #6  
Old 04-14-16, 08:49 PM
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I wasn't planning on any wire runs outside, it'll all be inside in conduit. I didn't realize the welder only had a three prong plug as I haven't picked it up yet. Just have it picked out. The camper is the 4 prong 240v plug. I guess I thought since they both were 50 amp 240 they'd have the same connector. I'll just run 2 outlets then.

Was just looking at the 6awg thwn-2 wire at Lowe's, it's .89/foot. 4awg is .86/foot. I'll probably just pick up the 4awg!
 
  #7  
Old 04-14-16, 09:34 PM
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Of course now I'm thinking about a sub panel in the garage... I have a 100 amp sub panel next to the main that is almost empty. That is why I hadn't really considered it before. But, im also running 2-20 amp circuits, a 30 amp dedicated for a 60gal compressor, and of course the 50 amp. Decisions decisions...
 
  #8  
Old 04-14-16, 10:02 PM
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it'll all be inside in conduit
Yes but the conduit will be outside won't it? Inside conduit doesn't mean it is inside if the conduit is outside.
they both were 50 amp 240
no the welder is 240 the other is probably 120/240.
Was just looking at the 6awg thwn-2 wire at Lowe's, it's .89/foot. 4awg is .86/foot. I'll probably just pick up the 4awg
but you need three #4 and one #8 so figure the price accordingly.
 
  #9  
Old 04-15-16, 07:12 AM
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Conduit would be all indoors. I have the ability to go straight into the wall from the panel with existing wires and into the basement, run along floor joists till it pops through into the garage at which point it'll be in conduit.

However, this might be a mute point. I'm starting to lean towards running a subpanel in the garage. I need to get out there tonight and look at the existing panels again. The main panel is full, I know that for sure, and the sub has only about 4 breakers in it with lots of empties. Going from memory, but I believe the sub panel is a 100amp with a 50 amp main breaker. Need to look at it again to confirm the number of breakers and the size of the subpanel main breaker and gauge of wire feeding it.

Sounds like I'll probably need to move a few circuits to make room for a breaker in the main panel to feed the garage subpanel.
 
  #10  
Old 04-15-16, 09:20 AM
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If all inside you may not need conduit. Perhaps SER can be used the whole way without conduit to a subpanel.
 
  #11  
Old 04-15-16, 11:28 AM
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+1 for SER. If you can fish through the wall no need for conduit. #3 should be fine for a 90 amp feed.
 
  #12  
Old 04-15-16, 08:10 PM
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Ok, my memory isn't so good. The sub panel is a 200 amp Eaton. There's no kill switch in the sub panel but there is a 50 amp breaker in the main panel. I can't tell the gauge but each wire is about a 1/4" thick. I attached a photo in hopes someone with more trained eyes might be able to tell what it is. It's stranded aluminum and it's all wrapped up in a grey jacket. The jacket is cut right at the exit of the main panel and right at the entrance to the sub panel.

After more detailed inspection, there's no way I'm running wire in through the wall or moving existing breakers to the sub panel. Everything is behind the wall, behind the panels, no access.

Looks like I have to run a new wire to the sub panel outdoors between the two panels with a larger breaker in the main panel. Can I put a 200 amp breaker in to feed the sub? Or what is the largest I can put in? Then, I'll need to run the garage sub panel off the other sub panel with a conduit down the side of the garage about 10-15 feet. I'd like to make that a 90 amp feed. It's going to feed 2-20 amp circuits of outlets, a 30 amp 240v for a compressor, a 240v 50 amp RV service and a 50 amp 240v outlet for a welder. Does this sound like a good plan? I'm open to other suggestions. Also, I need to keep in mind when doing this that we'll be finishing the basement in a couple years and will probably need another sub panel in the basement for that. I don't want to do anything right now that will screw me over over for that! I'd prefer to set myself up for that. Like leaving room in that original sub panel to run a second sub panel from it, if it's even legal to do that!

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  #13  
Old 04-15-16, 09:32 PM
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There's no kill switch in the sub panel
Not required because they are in the same structure.
Can I put a 200 amp breaker in to feed the sub?
Would probably exceed the stab rating for your main panel. Look on the label for the stab rating.
no way I'm running wire in through the wall or moving existing breakers to the sub panel. Everything is behind the wall, behind the panels, no access.
All you would need to do is remove the Sheetrock above or below the panel. Looks like they go down so below. If your not good with Sheetrock you can install pre made access panels when finished. They'd actually be an advantage making future work easier.

Please post a picture of the main panel.
 
  #14  
Old 04-16-16, 10:20 AM
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I'm good with drywall, it's the look on my wife's face when I tell her I'm cutting a hole in the pantry in her new house that I'm not crazy about! Actually, putting in an access panel is a good idea for the future. I think they should just have to do it from the get go when building a house, at least if it's in an inconspicuous place like the pantry. I'll do it when she's not around and put a nice panel in, she probably won't ever notice.

Any way, here's pictures. I took a picture of inside the main pane as well as the sticker on the main panel and the sticker on the sub panel. Sorry, I had to split both of them in two. The tall sticker is the main panel and the wide horizontal sticker is the sub panel.

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  #15  
Old 04-16-16, 12:00 PM
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Just move a couple of lightly used 15a/120v circuits in the main over to the sub to make room for the 90 amp breaker.
 
  #16  
Old 04-22-16, 09:20 AM
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Just stumbled onto a possible option that wouldn't require opening up the drywall. Is there anything wrong with using an Eaton BQC225225 breaker to combine the 2-25amp 2 pole breakers for the 2 air conditioners? That would open a double slot for a 90 amp breaker for the garage subpanel. I attached a, hopefully, better picture of the breakers in the main panel. Also, how close to maxing out this 200 amp service am I after the garage subpanel goes in given it already has the other subpanel? Just a reminder, I'll be running a 50 amp RV outlet, a 50 amp outlet for a welder, a 30 amp for a 60 gallon compressor and 2-20 amp circuits for outlets off the garage subpanel. I'm curious because I will be finishing the basement in a couple years, about 1400sqft. Nothing major going in the basement planned, just outlets and lights. Wondering if I'll have to have additional service to the house run.
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  #17  
Old 04-22-16, 10:16 AM
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Also, how close to maxing out this 200 amp service am I after the garage subpanel goes in given it already has the other subpanel?
The chances of maxing out the 200 amp service are pretty slim, but you can do a load calculation on the house and another on the future garage equipment if you feel you are getting close. I don't think you are even close.

Is there anything wrong with using an Eaton BQC225225 breaker to combine the 2-25amp 2 pole breakers for the 2 air conditioners?
I have never been a fan of the quad breakers. I believe that before I'd add a quad that I'd replace the 50 amp breaker and feeder to the existing subpanel and upgrade the feed to 125 amps and feed the garage subpanel 90 amps from the existing subpanel.
 
  #18  
Old 04-22-16, 11:50 AM
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That is a good idea too. If I upgrade that subpanel to 125 amps, would that be enough to service the finished basement circuits as well directly from that subpanel? That subpanel currently has 20 empty slots and is a 200amp panel. Just not sure if 125 is enough to run what is currently in there, the 90 amp subpanel in the garage and then add circuits for the basement when the time comes. What wire should I use to feed 125, I'd prefer to use copper? There'd need to be a conduit added between the two panels, about 8 inches or so, metal or plastic doesn't matter to me. Which would be better?
 
  #19  
Old 04-24-16, 11:50 AM
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Assuming your home is fairly typical, you really don't have that much load. I see no reason that 125 amps wouldn't be fine. I seriously doubt you'll ever come close to 90 amps in the garage either. You have a lot of just-in-case excssive power in your plan.

I'd use #2 copper THHN in EMT conduit to feed the subpanel.
 
  #20  
Old 04-25-16, 12:45 PM
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Started to pick stuff up for the project as budget allows. I grabbed the Eaton 125 amp panel at Lowe's, the one with the 5 20 amp breakers included and 2 of the Eaton 125 amp breakers. I was planning on upping the existing subpanel to 125 amps and then doing 90 at the garage subpanel. But, Lowe's had the Eaton 125 amp breakers on sale for $0.75 apiece! I realize I don't need 125 amp for the garage subpanel, but at that price why not! So, I figure I'll run 1/0-1/0-1/0-2 Al SER in 2" EMT conduit between the 2 existing panels and then the same wire from the existing subpanel to the new subpanel in the garage also in 2" EMT conduit all mounted to the exterior of the garage. I'll replace the 50 amp breaker in the main panel with a 125 amp breaker and use the second 125 amp breaker in the existing subpanel to feed the new subpanel. Does this sound like a good plan?
 
  #21  
Old 04-26-16, 05:19 PM
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I think it'll work. I don't understand why you would want to pull SER cable into a conduit system though. It's like wearing both a belt and suspenders. If I were going to install conduit I'd just install XHHW aluminum or THHN copper separate conductors.
 
  #22  
Old 04-27-16, 10:45 AM
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I was looking at the SER because it was easy to get here locally. I see your point though and did some searching around. I think I'll use #1 XHHW copper. What is common practice, and code of course, for the ground in the metal conduit when running XHHW? I don't think it needs to be as big as #1.

Also, I can only seem to find #1 XHHW in black so I'll have to use colored tape on the ends. I don't think there's any issues with code here from what I can see since this is all bigger than #4, except maybe the ground wire.

Looks like I also only need 1.5" conduit rather than 2" conduit as well. Save a few bucks there
 
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Old 04-27-16, 12:23 PM
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If the metal conduit is continuous end to end it can serve as ground. If you want to run a ground, not a bad idea, you need #8 copper.
Also, I can only seem to find #1 XHHW in black
You won't find colors. Just use bands of colored tape. That is standard practice. The blacks don't need to be remarked (okay to use two blacks since their interchangeable), you will find green #8 so just the neutral needs marking.
 
  #24  
Old 04-27-16, 12:52 PM
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I'd prefer to run a ground, I guess it just makes me more comfortable. I'm surprised #8 is all I need! I was expecting only a size or two smaller. #8 is much more wallet friendly! Thanks for the info!
 
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Old 04-27-16, 01:03 PM
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If you actually are using #1 XHHW copper (130A ampacity @ 75C), the proper ground size is #6 copper. If you actually meant #1 XHHW aluminum (100A ampacity @ 75C), the proper ground size is #6 aluminum. Ground size is based on maximum possible amperage of the hots, even if you are choosing to breaker them lower.

Most conductors #4 or larger only come in black. Standard practice is to mark with colored tape.
 
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Old 04-27-16, 01:24 PM
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ibpooks
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If you actually are using #1 XHHW copper (130A ampacity @ 75C), the proper ground size is #6 copper. If you actually meant #1 XHHW aluminum (100A ampacity @ 75C), the proper ground size is #6 aluminum. Ground size is based on maximum possible amperage of the hots, even if you are choosing to breaker them lower.
It's good you pointed this out. A lot of folks don't know the equipment ground has to be increased in size for what the ungrounded conductors are rated for, not just by the amperage limit of the breaker. NEC 250.122(B) covers this requirement.
 
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Old 04-27-16, 01:27 PM
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I'm figuring on #1 XHHW copper since I need the 130A capacity as I'm using 125Amp Eaton BR2125 breakers.
 
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Old 04-27-16, 01:39 PM
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In that case you will want to bump up to the #6 copper ground which is matched with circuits of 101A - 200A. Bare or green insulated is allowed - you won't find green in XHHW, but maybe in THHN. Technically you can't remark black #6 although I've never seen an inspector have a problem with it...

BTW, with the "round-up rule" your hots & neutral can be #2 copper (115A ampacity @ 75C) rounded up to the next standard breaker size of 125A. Ground sizing remains the same. Not much difference but could save a few dollars.
 
  #29  
Old 04-27-16, 07:34 PM
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I'm figuring on #1 XHHW copper since I need the 130A capacity as I'm using 125Amp Eaton BR2125 breakers.
Copper XHHW is hard to find and usually has to be special ordered. If you definitely want to use copper, I'd use THHN/THWN conductors which can be found almost anywhere.

BTW, with the "round-up rule" your hots & neutral can be #2 copper (115A ampacity @ 75C) rounded up to the next standard breaker size of 125A. Ground sizing remains the same. Not much difference but could save a few dollars.
Agree
 
  #30  
Old 04-27-16, 08:23 PM
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I did a bit of reading about the differences between THWN and XHHW. Course it's the Internet, but, it sounds like XHHW has better outer insulation and I ran across something about THWN installation needing to be above 14 deg Farenheight. I live in Colorado and the majority will be in conduit outside above ground. So I thought XHHW would be the better choice. I figured it might be worth the few extra dollars. For the quantity I need in #1 copper, it'd only be about $30 more. Since I saved a ton on the breakers, I figured I'd splurge on the wire. But if I'm really just wasting money and really isn't any real benefit, then THWN it is. Dropping to #2 would be an even bigger savings though! Is that possibly something the inspector would complain about? I'd read about the round up thing before but figured it's a homeowner DIY job and the inspector might complain
 
  #31  
Old 04-28-16, 09:16 AM
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Round-up is common practice based on NEC -- the inspector shouldn't flag that.

XLP insulation (XHHW) is thicker and tougher and consequently stiffer to work with. It is the same material direct burial service cable and overhead power company cable is made from. Thermoplastic (THHN) insulation is a little thinner and more flexible. Since you're running in conduit there is really no reason you would need XLP as the conductors are fully protected by the pipe. The low temps are only for installation day for flex during the pull, once installed it's irrelevant.
 
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