Garage Electrical Install Questions

[Kevin Dressel]

Hey all!

I am in the early planning stages of what will eventually be a 2 circuit wiring job (using NM 12-2) for my new attached garage. But, as you might have guessed, I've got a few questions (actually a few more than a few) that one of you folks might be able to help me with.

First, I'll fill you in on the background a bit. My ranch house used to have a two car garage built into the basement. I didn't like that arrangement, so I had a new two car garage built on that end of the house (where the old "garage" was). The new garage is fastened to the exterior brick wall of the house and opens into the basement (which will be finished...in time). The garage roof is built using trusses as you'll see in the photos (I'd like to use some of the empty space up there for light storage....holiday stuff, small boxes, etc.) The garage interior will eventually be drywalled and finished as well.

Anyway, I am now ready to feed electric into the new garage. My current intention is to run two circuits - one for the outside outlets / lights, and one for the interior outlets / lights.

That being the case, I've been reading up on wiring - both on the web/usenet and in several reference books - and I think I'm now ready tackle this project. Prior to submitting the permit application, however, I'd like to pick some brains on a number of concerns I've encountered while planning out the project. I posted some photos of the garage to help explain what I'd like to do. Web address is below. So, in no particular order, here I go....

1. What is the appropriate distance above or below an outlet box (and if it applies, a switch as well) to drill the hole through the stud? One reference calls for 6-8" above or below the box, while the other calls for 12" above. Does above or below really matter? What drives the hole location? The distance at which you staple the NM to the stud? If it makes a difference (though I don't really see why it would), I do plan on slapping nail plates on the studs.

1. When encountering a window (or door), is it best practice to go below the window (or above the door) through the cripple studs, or run the romex through the attic space? Going through the cripples would save romex and the need to protect the cable running through the attic, but if there is a compelling reason to go up and over, I will plan it that way.

Also, if you go through the cripples, is there a distance away from the door/window you have to be? None of my references mention that, though they do mention the alternatives I state above. Of course, one of the books states that it is also acceptable to run the cable through the shimmed space around the door, although I don't think I'd want to do that, especially if later owners decide to take the door out and end up cutting through the cable.

1. Speaking of running romex in the attic space, I will have to for the sake of the outlets in the ceiling powering the garage door openers, as well as the three carriage lights on the front of the garage (go from one light up into the attic space over the garage doors then down to the next). In both cases, the wire will have to run perpendicular to the truss bottom chords (again, see pictures for clarification). Can 3/4" EMT be used as an adequate protection for the cable for the short runs (15' or so) in the attic? My reference books talk about making a track out of 2x4s and 2x6s that would sit on top of the chords, but that's a bit of a pain, and at current lumber prices, a fair bit more expensive, not to mention heavier, and they seem to offer only minimal protection from above. If EMT is allowable per the NEC, do I have to run the individual wires in it, or can I run the romex as is? I have seen EMT run vertically on walls with the romex inside it as is. I know this is a heat issue (and hence can result in derating of the romex), and I'm curious if the requirements change according to the length of the run within the EMT. Also, whether using the track or the EMT, what sort of protection do I need to provide for the few inches of exposed wire at the ends before the cable is fed back down into the garage wall?

1. On the side of the garage attached to the house, I was planning on using 2x2 strips attached to the concrete / brick to support the drywall. For electrical cable run along that wall, my intention was to use 3/4" EMT and just have rather large notches in the 2x2s (which I don't like either, but since I can fasten the boards directly to the old exterior wall, it would likely be OK). However, I just started wondering whether notching the 2x2s on the back side (against the existing house) and running the romex flush against the concrete/brick wall would be sufficient (i.e. much smaller notches since the EMT would be out of the picture). The wire would be at least as far away from the drywall as any other wall in the garage, and there is little worry about hitting it from the other side (unless someone decides to bore through the 8" of concrete foundation). Thoughts?

In the end, if I have to go with 2x4s for a "standard" stud wall, I guess I will.

1. Although I can likely work around this, another question pertains to drilling up through the bottom chord of the two end trusses to get the wire up into the attic space. I don't expect a structural concern since they are both fully supported by other means, but I thought I'd ask.

1. Now, regarding running the two romex cables into the basement (and to the service panel), I will have to go through either concrete or brick, though I haven't measured yet which one it'll be (probably brick). In either case, I'll have a hole going through anywhere from 4 to 8" of masonry. Can I feed both runs through a single hole, or should I drill two? Not a big deal, just extra effort.

2. Last question....for now anyway....has anyone ever experienced interference running electrical along side the control wires for the garage door (particularly, these are the ones that lead to the safety beams near the bottom of the garage door).

Sorry for the rather lengthy post, but these are the questions that make be go hmmmmm....

Pics of the garage are located at:

If you would like to see additional pics, I can certainly accommodate.

Thank you all a lot on this!

Regards, Kevin

P.S. If you respond to me directly, take the _ out of the return email address, but I will be checking this newsgroup regularly.

[RBM]

Just drill the holes in the center of the studs

Do what's easiest for you. Sometimes using a little more cable will save a lot of drilling. Don't install cables anywhere where they could be hit by nails or screws

Use wood or PVC for suplimental protection. Metal conduits can cut the plastic and become energized, unless bonded

Notch the back side and use nail plates on the front

One hole is fine, don't make it to small

[<kjpro]

Seriously, call an electrician to have this DONE RIGHT for you.

2 circuits wouldn&#39;t even cover the lighting circuits I put in my 2-car garage!

[Terry]

I think you would get more feedback if you broke up each question or two and posted them separately.

[J.A. Michel]

I ran a sub-panel to my garage. You may want to reconsider your plan. It&#39;s always better to over do it the first time than to redo it a second time. I have control wires for door openers and electrical in close proximity in my garage...no problems with it.

[Chris Friesen]

Note that the last word in any electrical stuff is your local inspector. You might want to run everything by them when you get your permit. If there is a simplified code book available for your area, get it and read it.

Make sure you keep it light. Most trusses (unless specified otherwise) aren&#39;t rated for loads of that type.

If you ever forsee using the space as a shop you may wish to consider a heavier feed cable and a subpanel, along with extra outlets along the walls. It would cost more, but would make future expansion MUCH simpler. I recently bought a house and had to pull off the drywall and insulation so I could rewire the garage.

Usually it doesn&#39;t matter where the hole is as long as the wire is stapled close to the box.

Go below.

Common sense would dictate far enough away that nails/screws going through the studs won&#39;t hit the wire.

Normally romex in EMT is a no-no, except for very short runs (a few feet or so) used for mechanical protection. Around here cable in the attic generally doesn&#39;t need mechanical protection since it&#39;s above 5&#39;.

Don&#39;t see why you can&#39;t use one hole...just make sure that there are no sharp edges that could fray the cable.

Ideally you don&#39;t want them running parallel for long lengths. You certainly are not allowed to put them in the same conduit.

These are also the questions you should ask your inspector. Part of the benefits of a permit is that they&#39;re supposed to be available to answer questions based on the specifics of your local codes.

Chris

[Steve Barker]

what the hell are you lighting? even a 15a single circuit is about 5 times what you need in a two car garage.

[<Chris Young is a Hack>]

I knew that was coming... LOL

It&#39;s a 2-car garage/storage/workshop. :-)

I have 3 - 15 A lighting circuits.

1 covers the main inside and front outside lights (900 watts) 1 covers the side work area, extra lights around shelving and the attic lights (750 watts) 1 covers the front work area and the outside peak light (725 watts)

But more importantly, this guy wants 2 circuits...

1 inside (for everything) 1 outside (for everything)

[Joe]

Agreed. My one car garage/shop 26&#39; x 26&#39; has 2 circuits for lights (1100 watts total) and 1 for AC, another for a welder, 4 for GFI wall outlets, one for &#39;office&#39;, 1 for (ahem) refreshment fridge, 1 for heating system, etc. Service panel is QO Square D 100 amp. Might have to add a sub panel for a better air compressor 5 HP or better. Maybe should have put in 200 amp...

Joe

[<kjpro]

:-)

[Edwin Pawlowski]

Find out what the load carrying capability is before you do that. Trusses are designed to hold a lot of weight on top of them, but not to act as a floor with weight pulling down.

You are not ready yet. The questions you have should be covered in a good book. You need to read up a bit more if you are going to tackle the job.

Most garages end up with some power tools too. What circuit are they going to be on? Surely not the lighting circuit because you don&#39;t want to be standing in the dark when an overloaded saw kills the breaker. Putting in that circuit now is much easier than later. Using 14-2 for lighting circuits makes sense too as it will be cheaper, easier to work with; use the

12-2 for the receptacles. Consider a sub panel for your setup.

You need more help than we can readily supply here.

[Kevin Dressel]

Thanks all for the responses!

I already have a wood shop set up in the basement, so I don&#39;t really foresee using the garage in that way. The closest I would come is wheeling my table saw (contractor saw) outside for some cuts or maybe a few lighter tools on occasion. No plans for a refrigerator out there either. Frankly, there&#39;s just enough space for two cars and a motorcycle.

However, I will consider the subpanel idea for the sole purpose of expansion.

But, the only "constant" loads would be the three fluorescent lights (6

40w bulbs total), and maybe a radio. The outside lights will probably amount to 240w total (say, 4x60w), still far below a 20A circuit. But, as many suggested, plan for the future. Cost is inconsequential to doing it correctly.

In any case, I will run all of this past the inspector. I just wanted some preliminary feedback.

Regards, Kevin

[jJim McLaughlin]

All your questions are answered in your local codes and the NEC.

Quick personall observation: You are being cheap and not thinking ahead. You don&#39;t have enough circuits.

Romex is cheaper than labor. You don&#39;t want to do tis twice, going back late to add additional circits.

Lumber is cheaper than labor. Don&#39;t skimp on 2 x 4s by trying to go with 2 x 2s.

If ou us conduit, yu are going to wind up pulling wire. Thats a lot of work. Rethink conduit.

IMHO, you need at least 3, probably 4, 20 amp circuits.

Bear in mind, you can only have 7 items per circuit. This is a garage. Garages have a tendency to naturally evolve into workshops. Workships with table saws, drill presses and probably compressors. Garages also frequently sprout freezers.

Were it me (and it was about 25 years ago), I&#39; have one circuit for overhead lighting; a separate circuit for the 3 exterior lights and exterior, GFCI weather proof sockets (one in front, one on the side and 1 in back - you&#39;ll never have enough outside plug ins for yard tools ), and at least one and probably two for wall plugs every 6 feet around the interior perimeter of the garage. I&#39;d run the two garage door openers off the overhead light circuit.

Kev> Hey all!

[RBM]

Where in the NEC, does it specify only 7 items per circuit, in a dwelling?

[Doug Miller]

[...]

Where&#39;s that in the NEC?

You missed something important in the original post -- this part:

If the OP is going to have a garage evolving into a workshop, it&#39;s gonna be the one that&#39;s already inside the house, not the new one he&#39;s asking about wiring.

[Kevin]

Agreed! I like to think that most things electrical are based on common sense.

Since I don&#39;t have a copy of the NEC, I don&#39;t know specifically what it says in regards to romex in conduit, but there sure has been a ton of discussion on the subject. Problem is that half of the discussion condradicts the other half. As you mentioned, the inspector has the final say, so I will be asking him.

Excellent point here! I&#39;ll make darned sure the hole is both big enough to accomodate the cable and softened up around the edges.

As I mentioned earlier, I will be running all of this past the inspector. However, in my town, there is only one guy who handles a multitude of tasks (he&#39;s the fire chief, head of zoning, electrical, and a number of other things) so he&#39;s almost always busy and pretty hard to get hold of (I&#39;ve tried a couple times already). Hence my reasons for touching base here first.

Cheers, Kevin

[Kevin]

I don&#39;t understand the need for two circuits for 1100 watts of lighting, other than, perhaps, wiring convenience. Heck, a single 20A will still give you a 10+ amps of additional capacity to play with. Bragging rights, perhaps???

[Doug Miller]

I have, and I do. There is *no* NEC violation involved in putting NM cable ("Romex") in conduit in any location where the cable is permitted to be

*without* conduit. Anyone who claims there is, is invited to cite the article of the Code which says so.

Yep. Always best. There may be prohibitions in your local building codes that are not in the national code.

Hold on a minute there. NM cable is *not* permitted to be embedded in masonry. It *is* permitted "to be installed or fished in air voids in masonry block walls." [Article 334.10(A)(2)] You&#39;d better check with your local electrical inspector to see whether he thinks this specific installation is "embedded" or "fished in [an] air void".

Or you could install a conduit through the concrete wall, and run your cable through the conduit.

[Kevin Dressel]

Well, I do know the permit application states that electrical work will be done to the "National Electric Code, NFPA 70", so there shouldn&#39;t be any surprises beyond the NEC rqmts (I&#39;d hope anyway).

Yeah, I thought about the conduit through the masonry, not so much for the reasons you&#39;re stating, but for the sharp edges comment. Of course, depending on the size of wire I need to pull through, I&#39;ll have to find a pretty large masonry bit (I actually have one as large as 5/8", but that&#39;s it). If I decide to go the subpanel way (maybe 60A) - and I just might the more I think about it, I figure I&#39;ll need a pretty good sized hole.

Thanks Doug!

Regards, Kevin

[Kevin Dressel]

My reasons for using 2x2s rather than 2x4s was to minimize the end width of the wall between the basement and the garage. Since the doorway is currently mounted in the 8" foundation wall, adding 2x4s in a conventional manner would result in a roughly 12" width. Starts getting excessive in my opinion. If someone was to finish the inside wall as well (I plan on leaving this part of the basement unfinished), using

2x4s there as well would make the wall width 16". Starts to feel like a small hallway!

In the end, cost is not even factoring in the equation (well, may a little, but definitely not the driver).

By biggest problem with the 2x2s was protecting the romex. But, as I mentioned in the initial posting, I could run the romed flush against the masonry wall, and just notch the back side of the 2x2s. This would put the romex far enough back to meet the edge distance requirement. But, would that be legal?

Cheers, Kevin