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Small shop / electrical help.

5K views 54 replies 15 participants last post by  bigun 
#1 ·
I am building a small shop 16x10 and want to put 3 outlets in it and one light on a switch. I want one outlet for my welder and compressor and the other two just for small tools and radio.
I plan on running wire from the panel in the house to another small pannel in the shop.
Is this the best way to do it? and what size wire should I run from the house ? and also what size fuses?

Thank you.
 
#3 ·
Welder is 110 volt 25-140 amp. Compressor is 110 volt 15 amp.
Service to house is a 200 amps.
I have 6 extra spaces and the shop will be 5 feet from the side of the house. A total of 17 feet from the panel if I go underground.

Thank you.
 
#4 ·
I would run 3 #4 copper and 1 number #6 be nice to your self use 1 1/4 or 1 1/2 PVC pipe.Use a 100 amp two pole breaker in your main panel connect 2 of the #4s to it, the 3rd #4 mark white either with tape or paint and connect to neutral buss. The #6 mark green and connect to the ground bar. On the sub panel you can have a main breaker or not (I would because in an emergency it will allow you to shut all the power off at once) connect the 2 wires from the breaker in the main panel to either your main breaker in the sub panel or to the buss bar if panel does not come with main breaker there will be two clamps that connect to the breaker spaces that is where you land the first two wires. The white wire connect to the neutral buss. Be sure your sub-panel has a separate ground buss in the sub-panel only grounds connect to ground buss and only neutrals connect to the neutral buss. When you look in your main panel you will probably see them mixed they must be kept apart in the sub-panel. Be sure to look to make sure that neutral buss is not grounded in the sub-panel.as for wiring the garage I would use #12 for all you 110 receptacles and put them on 20 amp breakers. From the info you give you should be able to run most of your equipment off 20 amp circuits. I am confused on your welder is 25-140 the output? I hope this helps you if not let me know. Oh just to assure everyone that I have some idea of which I speak I own a small electrical contracting company and have been in the trade for 13 years.
 
#5 ·
Because the shop is ONLY 16X10 and only 17 feet from the panel, I would just run a 30 or 40 amp breaker (used for dryer or stove) on the main panel and run a 3 wire #10 to a small sub-panel (4 - 6 breakers). Because this is a convenience panel I wouldn't worry about running large wire to it, chances are you would never be welding and using a compressor at the SAME TIME. I would then run a couple of 12 ga. runs to a few plugs using a 15 or 20 amp breaker. If I got a larger welder or compressor that used 220 V, I would deal with it at that time by adding a 30 amp breaker (DPST) for a dryer or stove plug so I could plug the welder or compressor in. The other plugs would remain as is and on line because you would never run them all at the same time.
 
#7 ·
I like bigun's way best. But then again I believe in building for more that I will ever need. That way you only have to buy and run wire ONCE.

What ever size you do run, IMO you should connect the wires to the main house panel absolutely LAST. Have all other wiring done then connect to the main panel.

Just because the breaker is off does not guarantee it won't get "ACCIDENTALLY" turned on when you least expect.
 
#8 ·
bigun said:
I would run 3 #4 copper and 1 number #6 be nice to your self use 1 1/4 or 1 1/2 PVC pipe.Use a 100 amp two pole breaker in your main panel connect 2 of the #4s to it, the 3rd #4 mark white either with tape or paint and connect to neutral buss. The #6 mark green and connect to the ground bar. On the sub panel you can have a main breaker or not (I would because in an emergency it will allow you to shut all the power off at once) connect the 2 wires from the breaker in the main panel to either your main breaker in the sub panel or to the buss bar if panel does not come with main breaker there will be two clamps that connect to the breaker spaces that is where you land the first two wires. The white wire connect to the neutral buss. Be sure your sub-panel has a separate ground buss in the sub-panel only grounds connect to ground buss and only neutrals connect to the neutral buss. When you look in your main panel you will probably see them mixed they must be kept apart in the sub-panel. Be sure to look to make sure that neutral buss is not grounded in the sub-panel.as for wiring the garage I would use #12 for all you 110 receptacles and put them on 20 amp breakers. From the info you give you should be able to run most of your equipment off 20 amp circuits. I am confused on your welder is 25-140 the output? I hope this helps you if not let me know. Oh just to assure everyone that I have some idea of which I speak I own a small electrical contracting company and have been in the trade for 13 years.
you might want to use #3awg wire, #4 isn't rated for 100A.

personally, i'd use 6/3 NMD90, it appears that you're not going too crazy with outlets and lighting and heavyduty tools. 60A is still a lot of power and with smaller wire and fittings it'll save you a bit of money. you might want to go to a supplier and get 100A priced vs. 60A and make an honest decision about what you will be doing in the shop and what tools you'll be using and then go from there.

JB
 
#9 ·
johnnymopar said:
you might want to use #3awg wire, #4 isn't rated for 100A.

personally, i'd use 6/3 NMD90, it appears that you're not going too crazy with outlets and lighting and heavyduty tools. 60A is still a lot of power and with smaller wire and fittings it'll save you a bit of money. you might want to go to a supplier and get 100A priced vs. 60A and make an honest decision about what you will be doing in the shop and what tools you'll be using and then go from there.

JB
Hmm did they change it in the 2005 code? We have always used #4 for 100 amp. I don't have 2005 code book yet and my 2002 is out in the truck.Depending on brand of panel price of breaker should not be a real factor most Square D are around $16. for the smaller 2 pole 20-60 the bigger 60 and up should be in the $20-$30 these are home depot prices off the top of my head so I could be off. As has been pointed out I believe in future wiring IE planning for what happens down the road. By running a 100 amp He'll be ready for most up grades by running in 1 1/4 PVC or larger(2 inch is my favorite) he will be able at a later date to repull wire in case of trouble. I would also run a phone line in which could double as intercom, but thats me I tend to over do it sometimes. LOL Good luck which ever route you go! Keep us informed.
 
#10 ·
bigun said:
Hmm did they change it in the 2005 code? We have always used #4 for 100 amp. I don't have 2005 code book yet and my 2002 is out in the truck.Depending on brand of panel price of breaker should not be a real factor most Square D are around $16. for the smaller 2 pole 20-60 the bigger 60 and up should be in the $20-$30 these are home depot prices off the top of my head so I could be off. As has been pointed out I believe in future wiring IE planning for what happens down the road. By running a 100 amp He'll be ready for most up grades by running in 1 1/4 PVC or larger(2 inch is my favorite) he will be able at a later date to repull wire in case of trouble. I would also run a phone line in which could double as intercom, but thats me I tend to over do it sometimes. LOL Good luck which ever route you go! Keep us informed.
well, up here in Canada, that's all we sell is #3 for 100A. i'd have to check the code book also to get a precise rating.

anyway, i understand where you're coming from as far as building bigger than necessary, but you have to remember that this guy's shop is only 16'x10'. when he puts his car in there, there's not going to be much room left for tools so i doubt that he'd every really need that much power. i'm just trying to be realistic and not have him spend more than he needs to. however, it's a short run, so running 2" pipe would probably be a good idea for future additions.

JB


JB
 
#11 ·
While your running that 2" conduit, might as well put the cable in for tv, the sterio wires, alarm wires, security cameras, etc. When I first saw Smoke's post, I thought to myself, this guy has a nice little shop located beside the house that he likes to go out and putter around in. With a 16X10 shed, what kind of car are you going to put in there? I think Smoke's probably got the right size in mind for the work he does. Who knows, he may have a 80 X 120 building on the back 40 that he feels lost in. I have a 24 X 30 attached garage, a 30 X 40 working garage and a 30 X 45 car storage shed, but when I'm tinkering around, I always go to my 2 X 2 overcrowded space on the work bench to work, feels like home.

Smoke, forgot to mention to you, don't forget to put a double receptical convenience plug close to the bench or a strip socket on the wall by the bench. Allows you to keep your favorite tools and chargers plugged in. C U AL
 
#12 ·
Thank you all for your addvice. It is just going to be a little shop for my tools and doing some puttering arond in. Some place just to get away from the girlfriend. Dont tell her that :D . I dont have a big place so this is all the room I have so the car will still set outside but now I will have a place to put my tools besides in the utility room.
I think the 2'' conduit would be good for the tv cable also. Now If I could just get my cot set up and a mini frige the only time I will have to go in the house is for the bathroom.
You guys have some good ideas. I like this brainstorming thing.
 
#14 ·
2" pipe is a bit of overkill for 100a feed as 1 1/2" will meet code requirements as well as be a bit cheaper. bigun is giving you the best guide to doing it for sure. By NEC, #3 is what they call for, but by exception, in residential, #4 is allowed. Being that close there will not be a voltage drop problem with either size wire. And thats stranded copper wire too, not aluminum. The suggestion of running a couple of separate pipes, maybe 3/4" or 1", for catv and phone is a great idea as well since you only want to dig once. lol DO NOT run anything in your pipe which feeds power (the #4's) other than the 4 wires that bigun says. Run all the other stuff in their own raceways (pipes).

sounds like you were given some very sound advice. good luck!
 
#15 ·
ztoy said:
2" pipe is a bit of overkill for 100a feed as 1 1/2" will meet code requirements as well as be a bit cheaper. bigun is giving you the best guide to doing it for sure. By NEC, #3 is what they call for, but by exception, in residential, #4 is allowed. Being that close there will not be a voltage drop problem with either size wire. And thats stranded copper wire too, not aluminum. The suggestion of running a couple of separate pipes, maybe 3/4" or 1", for catv and phone is a great idea as well since you only want to dig once. lol DO NOT run anything in your pipe which feeds power (the #4's) other than the 4 wires that bigun says. Run all the other stuff in their own raceways (pipes).

sounds like you were given some very sound advice. good luck!
Whoops I am glad you caught the separate raceways for the low voltage :embarrass :rolleyes:
I am in the habit of using bigger pipe because I work mostly by my self and bigger is easier to pull through
:mwink: :mwink:
 
#16 ·
hey I know, bigger pipe always is better, makes pulling easier as well as it addresses future considerations. I work by myself too, been laid off for a while now so am out on my own working for myself. I have to tell you your the first guy who has given the 'right way to do it' help of all the advice I have read on here for the do it yourselfers.

:thumbup:

later...
 
#18 ·
Hey grouch how did your garage rewire project come out? As I told the fella who started this thread, I would prefer to do the job. But if I can't I will give the best advice I can to make sure that the work done is the safest way possible.
:thumbup: :thumbup: :thumbup: :thumbup:
Man spell check is a cool feature!!!!!
 
#19 ·
My garage is a never-ending project. They better bury me near it so I don't scare people on the way to "finish" some part of it.

The rewiring project had to take a lower priority than getting a roof on the extension. I have a 20 space, 100 amp box and a 2" PVC stub-out waiting for the other half of the trench to be dug. Now that I have a roof over my Olds, I'm beginning to feel a need for outlets and lights in that part. I still haven't purchased the wires to pull through that conduit, though. They will either be #2 or #3. (Thanks again to onenew32 and others in http://www.hotrodders.com/forum/showthread.php?t=63455 ).

There's a mess in my home box that has to be cleaned up also. All the grounds are paired with the neutrals under the lugs. Besides that, the only place available for a 2" conduit to enter the box has just a stub of a PVC conduit in it and a handful of 12/2 cables passing through that. Ugh!
 
#20 ·
You should see some of the stuff we do as professionals. I some times wonder if people are just that dumb, or have a death wish. Last year I bid on a 2100sq-ft addition onto an 1800sq-ft house built in the 50s some one had been there before and had installed a 200amp meter-main without permitting. they then put in a lot of recess can lights,A/C, 2 ovens and one stove top. Because of the size of the addition I had to upgrade the service to 320amps when we took down the old service there was evidence of charing around the splices, since the wire from the electric company was sized for the original 50 amp service not 200.
 
#21 · (Edited)
Man I agree on that one bigun, sometimes the clusterfu*ks we walk into almost make you want to walk away. My problem is I want to see that its right, for safetys sake so I usually wade in...lol!

grouch, I read the post you had linked to this one and I found it kind of hard to read (probably just me), but I read one from yours towards the end that seemed to show you were on the right track. Copper is better than aluminum. Longer lasting plus if you go aluminum you have to increase your wire size to equal the ampacity of the copper. There is more chance of corrosion using aluminum, plus it sweats and has a tendency, over time, to loosen in its lugs, causing arcing and a possible meltdown. But there is nothing wrong with using aluminum if thats your thing. Don't know about Ky, but here in Michigan the only way a panel in a separate building, fed from another panel, is considered anything other than a sub panel, is if the out building is connected to the main building by water pipes. If so, then you would run 2 hot wires and 1 neutral from the main panel and then the out building is considered to have its own system needing its own ground rod with it being bonded to the neutral. If no water pipe connection, then you would run an additional, properly sized, ground wire from the main panel, and the one in the out building would be considered a 'sub' panel off the 'main' panel. Now heres one option I haven't heard here, which is perfectly legal, given the right circumstances.

Run a small disconnect (sized for your panel to be fed) which is fed off your existing meter. Do this by attaching the feed wires going to the disconnect from the load side of the meter lugs. This is now a new system, and the disconnect is now your first means of disconnect of that system. So 2 hots and 1 neutral feed the disconnect. Install a ground rod at the disconnect. Run 2 hots, 1 neutral, and 1 grd. from the disconnect to the panel it feeds, keeping the neutral bar isolated from the grounded panel. No ground rod is required at the new 'sub' panel you just fed.

As far as the grd and neutral wires being under the same lugs in your house panel, do you mean the branch circuits, or the wires feeding the panel? If its the branch circuit wires, thats ok if the lugs are rated for that many wires. Some are, some are not. The grd and neutral should be bonded together in that panel already, so no problemo. Can you re-feed the 12's that are in the 2" pipe any other way? Its a big no no to run branch circuit wiring in the same raceway as feeders. I hate it when that happens..lol Like I said before, #4's are legal (Table 310.15B6) and will work fine for 100A in residential, but 2's or 3's will work too. 4's are just easier to work with and a little less expensive. (these are all copper wires I am referring to) Your bare copper wire size for the wire you run to your grd. rod only needs to be #6 also. NEC is usually updated every 3 years with significant changes in every addition. Make sure whatever book you use is current to the existing code. I'm not trying to be a know it all, just want to help a person get it right the first time. Sorry I ran on like this....

btw, whereabouts in Ky are you? I have relatives in Louisville, and the Tolu/Marion areas.
:cool:
 
#22 ·
My situation is not the same as smoke's. IIUC, he (she? no offense intended either way) is wiring a 16x10 *attached* shop. I would just wire the circuits from the house box as alittle1 said. 6 duplex outlets on GFCI breakers, a lighting circuit and maybe a 220V circuit if needed. Local codes will rule, naturally.

Mine is essentially a barn and has to conform to different rules.
 
#23 ·
Man I agree on that one bigun, sometimes the clusterfu*ks we walk into almost make you want to walk away. My problem is I want to see that its right, for safeties sake so I usually wade in...lol!

The same here call it professional pride I guess! Enough of the Hy-jack
Smoke or anyone else who needs electrical help feel free to PM or E- mail me
:welcome: :welcome: :welcome:
 
#24 ·
Dont worry about the hijach. I have gotten good info from you guys and am thankful for the help.
You are still talking about shops and electrical so it is all good.
I got the answer I was looking for Thanks.
The only thing that worries me is Grouch called me a he/she.LOL. Last I checked I was just a he. All in good fun.
 
#26 ·
smoke said:
Dont worry about the hijach. I have gotten good info from you guys and am thankful for the help.
You are still talking about shops and electrical so it is all good.
I got the answer I was looking for Thanks.
The only thing that worries me is Grouch called me a he/she.LOL. Last I checked I was just a he. All in good fun.
Please remember that this is by N.E.C. your local code authority may have other requirements. Good luck and keep us posted on your progress.
 
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