I am looking for suggestions and recommendations for adding electrical service to my two car garage. Besides the overhead outlet for the garage door opener, I have only one outlet in the garage.
The main breaker box is in the garage and will be upgraded when adding a sub panel for the garage. An electrician will be hired to install the new main and sub panel.
The walls and ceiling are uninsulated, sheetrocked, textured and painted white on 2 foot on center framing. The garage is 24′ X 24′.
Is there a recommendation for adding outlets along the walls?
I was thinking about surface mounting 110v outlets on the wall 4′ off the floor about 8′ apart. What kind of conduit is required/recommended in this situation? Is there a better solution?
Any guidance that you can provide will be helpful.
Steve Pippins
Replies
add more outlets than you think you'll need. They are like clamps. You never have enough.
Don't forget the 220V circuits.
AMEN!!
A bad day woodworking is better than a good day working -- yes, I'm retired!
If your main panel is right there in the garage, adding a subpanel probably isn't necessary (although I suppose it would be handy to have all the garage circuits grouped together so you could turn them all off at once.)
What activities do you have planned for the garage? A woodshop, working on the car, or just getting more outlets in handy places? Will there be any 240 volt equipment used, like table saws, air compressors, welders? Are you going to add lights? A basic outline of what you intend to do out there will help us envision the whole thing so we can make better recommendations.
If there's no insulation in the walls and there's access to the attic space above the garage, you may be able to run the wiring behind the sheetrock without knocking it full of holes by going up from the panel/subpanel into the attic, and then dropping down in the stud bays where the outlets will go.
For surface mount boxes and conduit (check first with your electrician to make sure what is permitted in your area) you could probably use EMT metallic conduit and metal boxes, or Schedule 80 PVC conduit and boxes. Schedule 40 PVC *may* be okay, but it is not as resistant to impact, particularly in a garage where it may get bumped. Again, find out what is common convention in your area.
Stuart, thanks for the feedback.
Maybe I will not need a sub panel after all. I bought the house last year and the inspector recommended changing out the 150 amp Federal Pacific breaker panel. The inspector said there were known safety issues with that brand but did not specify. I am not hard over on a sub panel for the garage but thought it would be preferred.
Primarily the garage will become a general habby shop. Basic woodworking, car maintenance, and some light welding. Your comments about overhead lights and 240 outlets are well taken. I do not have any 240 equipment right now but will add it and lights to the requirements list.
I considered dropping wire down in the stud bays but cannot see how I can get to the top plate in the attic to drill the necessary holes. Maybe I am missing a good technique here. To get access to the top plates, I would have to tear sections off of the hip roof. Let me know if there is a better way.
Again, thanks for the advice.
Steve Pippins
Old Federal Pacific panels are famous (infamous?) for causing problems, so it's a good thing you're getting the main panel replaced. Here's a web page with additional information on them: http://www.inspect-ny.com/fpe/fpepanel.htmAs far as trying to drill down through the top plates, it was only a suggestion as every house is different. If you have a hip roof I can imagine it's pretty tight trying to reach in there. Electricians have all kinds of tricks up their sleeves to do this sort of work - flexible drill bit extensions and fish wires, that sort of thing - but it may not be worth the extra effort in your case for a garage. Plus, surface mount conduit and boxes will be easier to add on to or reconfigure in the future.You could probably take care of most of your requirements by running a single row of conduit around the perimeter of the garage, with outlet boxes spaced every six or ten feet or whatever makes the most sense in your case. If you use double gang boxes and put in just 120vac outlets now, you could come back in the future, pull a few more wires and drop in a 240vac outlet here or there if you need one (although this will need a little advanced planning - you can only put so many wires in the conduit before you have to derate their current carrying capacity.)While it would be great to have a million outlets, each on their own circuit breaker, for casual use a person really doesn't need all that much, particularly if you're out there working by yourself. It's not like you'll have a half dozen machines all turned on at the same time. Probably the best thing to do is pick the electrician's brain a little when he's there to install the new panel, since he'll be able to look around and see the situation.
Edited 9/1/2005 2:00 pm ET by Stuart
I am not a Electrician but a Electrical Engineer...The inspector said there were known safety issues with that brand but did not specify...MAN! Would I get on his case for that statement!... STUPID information for you... As in NO information...Primarily the garage will become a general hobby shop. Basic woodworking, car maintenance, and some light welding.Go with a sub panel... PLEASE... I'm sure it will cost a bit more but worth every cent if sized right.. You never know what you will need and does not take away from the main structure if done right...
You didn't say where you were located, but.....
One of the main things missed in shop layout is conductor sizing
for the intended load and grounds. Look at the NEC, (or have your electrician do this) and determine what machine loads you have;
For example the 220v single phase cabinet saw likes a 30A breaker, but
most municipalities require a disconnect switch within sight of the machine as well.
The NEC says 12ga is good for a 220 feed up to about 60 ft, but you should go to at least #10 or #8 to minimize the inrush drop when that machine starts up. Just don't over breaker it. In other words, wiring with larger gauge wire costs more in the start, but you size the breaker for the load. Also seperate lighting circuits from outlets - you don't want to be in the dark with a running machine.
Code also requires GFCI in garages - so be prepared for that expense.
Make sure your electrician gives you alternatives in per outlet protection such as for portable tools. However, GFCI for a 220V stationary machine is expensive. And most inspectors will accept
a 4-wire installation (2 hot legs, one electrical ground and one
frame ground run all the way to the service panel.)
You'll be safer in the long run.
Duster1, thanks for the input. I am in Plano, Texas ( a Dallas suburb).
Good point about lights and machines on different circuits.
Steve Pippins
While your electrician is upgrading the main panel, ask him to install whole house surge supression. The units are only about $40. Not for your shop, but for the electronics in your house. It's another level of protection, or the only level for your equipment that is not already protected with portable surge supression.
Four foot is a good height for shop outlets. Don't put your lights on the same circuit as any of your outlets. If your floor is slab on grade your outlets would need GFCI protection.
If you will be working below 50°F you'll need incandescent lights or fluorescents rated for cold weather. Standard fluorescents dim and flicker below 50°.
It is unlikely that you want Ground Fault protection on your heavy equipment. If you rename your garage to shop, there is no code requirement for ground fault protection.
There is also no need to increase the conductor size about what is normal - #12 for 20amp, #10 for 30amp.
Metalic tubing is perhaps easier to modify than plastic.
If you have the required parking behind the building line outside of your garage, you can 'rename' your garage to 'the shop'. It sure would save on the requirement for GFCI in garages. That little stickler could get in the way with some inspectors. If you are stuck with the garage designation, no outlets are allowed below 18", so the four foot height would be in order. Its also handy as heck. EMT (conduit) comes in ten foot lengths. I therefore have outlets every five feet in my two car "shop". Running in conduit on the wall is fast and easy. I ran two 12 guage romex in the conduit so every other box is on a separate circuit. You just cannot put too many receptacles in a shop.
Your main panel may not be sized to handle the additional current load from your tools. If you live in Plano and have a two story house, then you probably have two air conditioners. That's a big load in itself! With everything in the house running for a while, feel of the main breaker switch to see if it gets hot. Mine was warm.
I put in a 100 amp sub panel in my shop and wired it directly to the meter (with a dis-connect mounted beside the meter). That kept the shop current out of the main house panel. You have to call the electric company for permission to disconnect the meter to make this connection. But, let your electrician do that. I also drove a 10' ground rod for the new shop panel.
I put in four 110V curcuits; one for the lights, and one for the outlets for each wall. I put in two 220V circutits for the larger tools. A 20 amp circuit breaker and #12 wire is handling my 10 flourescent light fixtures. I have 15 wall outlets on 3 circuits protected by 20 amp breakers using #12 wire; 5 outlets on each wall. The 220V outlets are using #10 wire.
PlaneWood by Mike_in_Katy (maker of fine sawdust!)
PlaneWood
Just a question. I don't really know the answer or if Code would have a problem with it.
But, if you mount your electrical outlets 4' off the floor and then lay a 4' x 8' sheet of plywood against the wall, what does that do to your electrical outlet?
Would 50" or 55" be a better choice of height? Does Code prohibit this? I've seen self-retracting extension cords suspended from the ceilings of some shops so I would think not. But, I am not an electrican.
You are correct about the problem with 48".I would recommend 48" to the bottom.
Took me a minute to figure out what you were saying, but I think I know now. You mean 48" to the bottom of the outlet box, right? That way the outlets themselves would be above 48" and available should a sheet of 4 x 8 be leaned up against the wall. Good point. Thank you for answering my concern.Griff
Ya know, I'm no expert, but I've wired a lot of buildings. Best thing to do is make a trip to the local building permit office and ask questions. Could save you a lot of time, and $$$. Each area is slightly different, but all adhere to the NEC. The building permit office generally (at least my experience has been so) is happy to give you information to help your job go smoothly.
And you seem to have an electrician you work with, ask him a few questions.
Good luck! Oh...and for what it's worth, I highly recommend the 3/4 inch conduit method. Course, I think it harkens back to playing with erector sets, but I love working with conduit. Doesn't take much time actually, and gives you a LOT of flexibility.
I don't have a code book here at home, but I believe that it doesn't matter what you call a room (garage, shop, or whatever), the requirement is that if you have a concrete slab on grade your outlets need GFCI protection. All the rooms I built with concrete slab on grade, whether basement, garage, or shop were all required by my inspector to be GFCI protected.
Why wouldn't you want to anyway?
"if you have a concrete slab on grade your outlets need GFCI protection."That would mean that most every house in Oklahoma would need GFCIs in every room.Cars parked in garages tend to make the floors wet when it is raining or snowing out. This is the reason for GFCIs in a garage. A shop should not make a floor wet.
I'm told in my state, AR, all 15 a. and 20 a. circuits must be 12 gauge. 14 gauge is no longer recommended (approved?) for 15 a. circuits.
I agree.. All my house is wired in 10 Guage.. I ripped out all the old stuff and put in nwe LONG time ago..10 guage was not that nuch more then..I had to get special outlets for the walls.. Not that much more either THEN! Not sure about now!And Ground wires.. Not needed then...EDIT:: I CAN spells if I'm not typin'!
Edited 9/6/2005 10:00 pm ET by WillGeorge
Should handle almost any typical woodworking needs. Also, if you ever need money, tear down the building and sell the copper! :-)
A bad day woodworking is better than a good day working -- yes, I'm retired!
When re-wiring my garage, the electrician made a very clean installation of new circuits by cutting a 4" wide path in the sheetrock all the way around the garage, running the wire, and installing a metal raceway to cover the wire. Actually allows me to change things later.
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