Wiring Garage/shop

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As you know I am working on wiring a detached garage/shop. I am a newbie. I have attached a link to my work thus far. I am having a little trouble figuring out how to route everything. Any helpful advice is appreciated.
http://www.flickr.com/photos/42254706@N03 /
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stryped wrote:

IANAE, but I don't think it's permissible per the NEC to have unsupported cable spanning across roof struts. Also, some localities may not permit exposed NM cable less than 7 feet above the floor. Around here it is customary to install drywall over stud bays with wires inside.
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stryped wrote:

Put messenger boards (fancy name for 1x3's) under the cables that run unsupported perpendicular to the ceiling joists.
Bob
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Where I am, the standard for romex in a garage is that it has to be run so that "you couldn't hang a coat hanger from it". Clearly you don't meet that standard, and we usually use conduit in garages. I guess the bottom line is that the romex running around the corner and also across the two trusses would be easily susceptible to damage in a garage.
JK
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Just a point to keep in mind...
Your lights should be a circuit of their own so that no power tool can trip them.
It sucks trying figure out what to do with that 4 x 8 sheet when the table saw trips the breaker and the whole room goes dark.
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My 11 outlets are in one 20 amp circuit. My lights will be on 2 separate 20 amp circuits. It is probably overkill but my thinking was if the GFCI tripped for one set of lights the other would stay on. (I have 10 plug in "shop lights" in the ceiling. Since they have to have outlets, they must be GFCI protected.
I have one 20 amp circuit for the back 6 lights, one 20 amp circuit for the front 4 lights and also on the circuit will be one or two outside flood lights.
Should I rethink this?
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My 11 outlets are in one 20 amp circuit. My lights will be on 2 separate 20 amp circuits. It is probably overkill but my thinking was if the GFCI tripped for one set of lights the other would stay on. (I have 10 plug in "shop lights" in the ceiling. Since they have to have outlets, they must be GFCI protected.
I have one 20 amp circuit for the back 6 lights, one 20 amp circuit for the front 4 lights and also on the circuit will be one or two outside flood lights.
Should I rethink this?
*I think that you should. You have more power for lighting than for equipment. Do you really need to use plug in light fixtures? You didn't say what you are planning to do in this space, but I would have put in several circuits for the outlets.
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Two 20 amp circuits and their required 12 g wire certainly seems like overkill for a bunch of plug in light fixtures.
re: "if the GFCI tripped for one set of lights the other would stay on"
I'd choose wired fixtures (or rewire the one's you've bought) and eliminate the GFCI from ever being an issue.
Wait, I take that back. Since just about every post in this thread has pointed out something that someone doesn't like, maybe you should consider putting down the wire cutters and stepping back from this project for a bit.
It certainly appears that you haven't submitted any plans for this wiring to the powers that be (maybe you don't have to in your locale) but since there seems to be a number of questionable things being discussed here, it might be time to look for help locally (and professionally) and not through a DIY forum.
Now hold on...I'm not "that guy" that says "Call a contractor" everytime someone asks for help, but since we are talking about a fairly large electrical installation here, don't you think it should be done correctly - to the utmost detail - in to ensure that you and yours are safe?
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*I usually use metal boxes in garages due to the firewall requirement. You should not install your wiring devices until after the drywall is installed. The routing of the cable seems fine except that Romex cannot extend over four feet without being supported. If the space above the ceiling is going to be an accessible attic space you will need to install running boards along side of your cables. Throw in a couple of nailplates in the corners to protect the cable from nails.
I see that you are using 12/2 for lighting. It sounds like overkill. Did you actually figure out what your lighting load is going to be? There is no need for a GFCI circuit breaker for your outdoor lighting however your garage receptacles are required to be GFCI protected including the one on the ceiling. A GFCI receptacle is cheaper than a GFCI circuit breaker and can protect receptacles downstream.
Since you seem to be using all 12/2 be mindful of the cubic inch capacity of your boxes. Each wiring device uses the equivalent of two conductors and must be considered when calculating your total number of wires in a box.
Since this probably a subpanel your ground wires in the circuit breaker panel need to go onto the ground bar and not the neutral bar. Grounds and neutrals are kept separate in a subpanel. You will need to run four conductors to feed your subpanel. Remove the green bonding screw from the neutral bar. I think that a main breaker is required in the panel for this installation, but I would need to look it up to be sure. If that two pole breaker in the lower left is going to be your main it will need to be held down with a screw or clamp. Check the panel labeling for the part number for this.
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My panel is "upside down" The instructions said to mount it this way if the panel will be "bottom fed". Which mine will. SO the ground buss is on the left and the neutral bus is on the right.
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My panel is "upside down" The instructions said to mount it this way if the panel will be "bottom fed". Which mine will. SO the ground buss is on the left and the neutral bus is on the right.
*The neutral buss is on each side and you currently have your ground wires connected to the left side neutral bar. You are supposed to connect each neutral below the corresponding circuit breaker for easy identification. The ground bar is that small little screw terminal strip on the left set back from the neutral bar. You can probably install at least two wires under each screw on the ground bar which is why it is so small. The panel labeling will tell you the number of wires per screw allowed. The label may also have a diagram of the interior of the panel confirming the neutral bar on each side.
Please tell me that you will be having this work inspected.
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I will double check but the bank on the right says "neutral" and the one on the left says "ground". I plan on using this as a garage and hobby shop. I was told I could have a maximum of 13 outlets on one circuit so I figured 11 was ok. I figured it would be rare to run more than one thing at a time.
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I will double check but the bank on the right says "neutral" and the one on the left says "ground". I plan on using this as a garage and hobby shop. I was told I could have a maximum of 13 outlets on one circuit so I figured 11 was ok. I figured it would be rare to run more than one thing at a time.
Sounds like your adviser is mistaking commercial outlet requirements for residential outlet requirements. There is no minimum or maximum amount of outlets per circuit. As John Grabowski points out, there is something peculiar about the neutral buss. I recognize the panel as a GE brand, and there should be a bridge connecting the two neutral busses, which I don't see.
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The person that advised me was the electrical inspector. He said to figure 1.5 amps per outlet. 1.5 x 13 = 19.5 amps. (all mine are 20 amp circuts.
i will double check when I get home but I really belive I only have one neutral buss and the other is ground. This is a 100 amp GE panel with 100 amp main breaker. Bought at Lowes.
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The person that advised me was the electrical inspector. He said to figure 1.5 amps per outlet. 1.5 x 13 = 19.5 amps. (all mine are 20 amp circuts.
i will double check when I get home but I really belive I only have one neutral buss and the other is ground. This is a 100 amp GE panel with 100 amp main breaker. Bought at Lowes.
It would be odd, for the panel to be built with a ground buss off to the side, as yours is, and another ground "only" buss set on insulators, as yours is. As I said, that panel comes with a bridge, that connects both sides of the neutral buss together. It's entirely possible that it was tampered with. Your electrical inspectors recommendation of figuring 1.5 amps per receptacle is fine, and I would figure fewer outlets per circuit in your situation, however that is a commercial calculation, not residential.
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RBM,
I know you are an expert on this stuff. When I am reading any threads on this forum that involve electricity, I always look for your replies to see what the real answer is. I also know that I am NOT an expert on any of this, and I have just been trying to learn what I can over the past few months.
But, I did just recently have two panels put in that are now subpanels, but which eventually will become main panels when I have new electric service put in. What I ended up doing was buy two main panels but set them up as sub panels for now. The main panels did come with a bridge that connects both sides of the neutral buss together. But there were instructions that said the main panel could be used as a sub panel by first taking out the bridge, and then tightening down a screw all the way on one of the busses that is on insulators so that buss will then be bonded to the panel itself. That made that buss a ground buss, while the other buss remained as a neutral buss that is mounted on insulators and is not bonded to the panel. According to the instructions, the other way to do this would be what you said -- both neutrals are insulated from the panel box and connected together with the bar in place, and then a separate grounding bar is added and mounted to the panel box. With this second option, the screw I mentioned earlier is left NOT tightened down, and that buss remains insulated from the panel box.
So, as far as I can tell, the panels are set up to allow either approach to be used when using that main panel as a sub panel. And, I think the OP may have his panel set up like the first option (with one buss bonded to the panel box and used as a ground buss, and the other buss remaining insulated and used as a neutral buss), and no bar would be in place connecting the two busses together.
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Thank you for the compliment. There are a number of very sharp folks on this newsgroup, and in all honesty, I come here to learn. To your point, you are absolutely correct. I've done exactly what you describe on numerous occasions. In this case, it appears that the "grounding" buss came installed in the panel, in which case I would have left the neutral buss alone, and I didn't get the impression that the OP was the one that removed the bridge.
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I verified tonight what the panel said. Left says 'grounding strap", right says "neutral strap". usint a continuity meter, left bank has continuity to the enclosure. Netral strap on the right does not.
Instructions call that little bar to the very left "addition" grounding connections.
By the way, I plan on having 2 240 volt circuits, one for an air compressor one for a lincol welder "buz box". I was going to make the compressor a 30 amp circuit with 20-3 wire and the welder a 50 amp circuit with 6 guage. Does it matter if I have bothe these breakers on the same buss as the 100 amp main breaker or would that be bad practice to have alot of voltage on one bank compred to the other?
Also, do I need to have these outlets a certain distance from the overhead garage door? I would like ot place them as close as I can so I can reach outside with them if I need to,.
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stryped wrote:

The 240V circuits will be bussed the same no matter where you install them in the box. (and you might want to look into GE 1/2" THQP breakers so you don't fill your panel up so fast)
Are your feeding this panel with a 3-wire circuit or 4 wires? Since the garage is detached, you can do it either way (with some restrictions on the 3-wire method.) It makes a difference on how you're supposed to hook up the ground.
You can use 8 gauge wire for that 50A welder and save a little money, plus #8 is easier to work with than any other large size (including #10) because it's flexible.
Bob
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It's probably not a good idea to even consider a three wire feeder. They're outlawed in the new code, and they restrict you from connecting anything conductive between the two buildings.

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