Electrical Wiring for garage!

[mechanicworkman]

Ok so I have been putting more thought into the wiring of my garage and need some info and feedback on what I need to do. I obviously know that hiring a electrician to do all this will get very expensive quick so I am hoping I can do some of this myself.

My house currently has a 200 main I want to have a 100 sub-panel out to the garage.

Since I will need a permit of some sort to do this I guess I will likely just hire electrician to wire in the sub and then do the rest of myself.


I would like to separate the garage wiring from the house and run it primarily off the sub-pannel in the garage. Meaning all lights garage door opener and outlets would be run off the sub in garage.

Hopefully that’s not asking to much and I am hoping I may gain a little room on the breaker in the house by doing that as well……………..mabe LOL

Now the lighting in the garage is very poor right now only got a few of the tube style ones there now.

Ultimately I am wanting to put a bunch of the can style recessed lights in the ceiling. Right now I have no ceiling just trusses overhead with bare walls no insulation inside garage. But, seems like I have heard its easiest to run wire first then hang ceiling.

I want to get the wiring all done so I can get some sheetrock/plywood walls up and start getting things organized.

Soo anyway on to the wiring............

I I been looking online and am finding that I can get a 1000’ ft roll of 12-2 romex for like 200 bucks............this stuff is expensive

Is it OK if I wire all the lights with the 12-2?

Outlets since i will have the outlets in the garage and the likelyhood of running power tools off them I am thinking all 20amp circuits everwhere is the way to go? Is this what others have done?

DO all 20amp outlets have to be dedicated to once circuit breaker or can I hook 2 or 3 of them together as long as any projected draw would not be over the 20 amp limit per circuit?

Is this my best way to go or should I figure in some 15 amp circuits and buy 500' of 12-2 and 500' 14-2

Is using larger diameter wire bad? Or is there a reason this would not pass some sort of code as most lights most likely are usually run off like a 14-2 is this correct?

So how many lights can of run off a single circuit?

DO I drill small holes in the trusses and then run 1 wire through each hole or do I just run wire over the top of the trusses?


I definitely wanna stay in code but then again I don’t know what codes I need to follow.

Nor do I wish to spend the next 6 months learning the electrical code only to wire a garage???



Are there some basics info I need to follow?
Like some do’s and don’t…….or some pointers others have learned
Any help would be much appreciated!

Hopefully this is not a task that I will be in way over my head.

 

[mechanicworkman]

What type of box do I have? And what kind of breakers do I have to buy to go with it?

.

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[RickP]

Lots of questions - I'll try to answer a couple of them:

Run your romex on top of the trusses. The outlets should all have 12-2 romex. You could use 14-2 for the lights, but many people prefer to use 12-2 instead. Your choice, but make sure you calculate the total amp draw for your new lights. I'd recommend keeping the old lights in service, in addition to whatever new ones you install, just so you'll have light when you do any wiring inside the subpanel. Also, you can use the old lights when you're just "passing through" the garage, and use the new ones when you need to work in the garage.

- Rick


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[theoldwizard1]

I been looking online and am finding that I can get a 1000’ ft roll of 12-2 romex for like 200 bucks............this stuff is expensive

Is it OK if I wire all the lights with the 12-2?

First, how big is your garage ? 1000' is a HUGE amount of wire. 250' would probably be more than enough. And $200 for 1000' of 12-2 is a very good price ! ($265 at HomeDepot)

12-2 is overkill for lighting.

Depending on the size of your garage, the number of new lights you are adding, the number of new outlets you are adding, you might need as little as 100' of 12-2 and 100' of 14-2

Hopefully this is not a task that I will be in way over my head.

It sounds like it is !

 

[rburke65]

Looks like a Cutler Hammer panel. At least that's what I think it says.

 

[Charles (in GA)]

Go easy on yourself and stick with one size wire. Use 12-2 for everything and you won't have any issues with having used the wrong wire, or have a combined receptacle/lighting circuit. The county north of me will not allow any 14-2 to be used anywhere in a residence (or attached garage).

For general purpose receptacles, you can have more on one circuit than is practical. For residence and attached garages, there is no limit, however for many situations, the code limits you to 180 VA per "yoke" which translates to 13 receptacles on a 20 amp circuit. Stick with 4 or 5 and you will be fine.

That is a Cutler-Hammer brand panel, a BR series (formerly Bryant). The BR series is important to know, because CH has another line of breakers and panels, the CH line, that DO NOT interchange with yours. For easy reference the CH line has handles on the breakers with a funny pinkish color, almost a light skin tone.

If the attic will have any access at all (ie scuttle hole via ladder) then all wires within 6 ft of the hole have to be protected by running them on running boards, or thru joists with running boards over them. Running wires on top of the joist is a code violation within 6 ft of the access.

Receptacle circuits need to be protected with GFCI, either using a GFCI circuit breaker in the panel for each circuit, or by using a GFCI in the first receptacle position in the circuit and supplying the remainder of the circuit via the load terminals (feed thru) of the GFCI receptacle. Buy good ones, do get the cheapest ones.

It will take a bunch of can lights to get decent coverage in a garage of any size, as cans focus light beneath them. People can and have used them in garages successfully, but there are other options. Simple T8 fluorescent lighting will provide a lot of light for a reasonable cost.

If you are finding NM (non metallic) cable cheap, make sure it is marked NM-B on the jacket and has the 90°C temp rating. Older NM had 60°C temp rating and you would have code issues using it. (in other words, make sure it is not someone's old stock they are dumping).

Charles

 

[mechanicworkman]

RickP,

What do i need to know to correctly calculate the load draw? I would assume that i need to find the light fixture i am going to use. Assuming that a light fixture for example it would run on 3.0 amps i would be able to put a max of 6 light fixtures on that circuit drawing that would draw 18 amps on a 20 amp circuit is this correct?

 

[mechanicworkman]

For general purpose receptacles, you can have more on one circuit than is practical. For residence and attached garages, there is no limit, however for many situations, the code limits you to 180 VA per "yoke" which translates to 13 receptacles on a 20 amp circuit. Stick with 4 or 5 and you will be fine.

Bare with me as I am new to this! But all the help is appreciated.

Sooo firgureing that each outlet at 20 amps and 20 times 9 equals the 180 max however I dout that I would be needing 9 on one circuit 4 or 5 per circuit and 2 or 3 circuits in the garage should be more than enough.

However somehow you are saying that there can be 13 receptacles on a 20 am circuit how can that be? The way above i thought it would have been only 9.


Does the garage door need its own circuit or anything funny like that?

 

[mechanicworkman]

That is a Cutler-Hammer brand panel, a BR series (formerly Bryant). The BR series is important to know, because CH has another line of breakers and panels, the CH line, that DO NOT interchange with yours. For easy reference the CH line has handles on the breakers with a funny pinkish color, almost a light skin tone.

I will watch out and make sure that i don't buy any of the CH style and only the BR series.......thankyou

 

[ddawg16]

Don't get hung up on current draw....common mistake...

Instead, look at all the possible loads you will have on at the same time.

Compressor (240Vac)
Lights
One tool....saw, drill press, grinder, etc.

If you have AC...ok....that is another potential full time load.

Add up the above...your lucky if you will ever go over about 30a at 240Vac...

I have 50A to my garage and have NEVER tripped the breaker...before my new load center it was 30a...never tripped that one either.

Outlets...you have have as many as you want on a ckt.....but I divided my by sides and floors.

Charles GA is giving you the best advice.....

I would suggest a sub-panel with a main breaker. If no main breaker, you can't have more than 6 breakers. The NEC seems to think that if the **** hits the fan and you need to start turning off all the breakers...it would take too long if there were more.

NEVER put lights on the same ckt's as outlets...you don't want to kill the lights if you trip the breaker.

If you have a lot of lights...divide them up into two breakers....adjacent breakers. That will help balance your loading...and...help troubleshoot. If you drop one leg of your 240Vac (for what ever reason), only half your lights will come on.

Put you wall outlets at least 50" or higher....that way you can lean a 4x8 sheet of plywood against the wall and not cover it.

You can never have enough outlets. Consider putting some in the ceiling.

Per the latest NEC....all of them have to be GFCI protected. You don't have to have a GFCI at each outlet...just do one at the start of the string and connect all the remaining outlets on the load side of the GFCI.

Do NOT back stab your outlets. Use a pig tail. If you don't know what I mean, look it up or let me know and I'll post a pic for you.

 

[Highbeam]

Great advice guys.

On the GFCI thing, a common method is to use a GFCI plug on the first outlet in a string. Non GFCI outlets are cheap so you start just putting in outlets every 5 feet and next thing you know, you've got 20 outlets downstream of that one GFCI. I don't know if it is a code but I have been warned not to exceed 8 downstream outlets, then another electrician told me 12. Ack

Are you putting a fridge/freezer in the garage? You don't want that plug to be GFCI so be sure that you put it somewhere near the first outlet in the string. I have run into problems where I want a non-GFCI outlet but since I protected the string way upstream, I can't get it.

I have just under 500 feet of 12/2 in my 30x60 so far with about 20% to go. The materials are cheap so go overboard.

 

[ez-duzit]

12-2 provides only line and neutral (for 110V). Pretty sure you need a separate ground to each light fixture and duplex receptacle, unless you run it inside metal conduit.

 

[Highbeam]

12-2 provides only line and neutral (for 110V). Pretty sure you need a separate ground to each light fixture and duplex receptacle, unless you run it inside metal conduit.

12/2 NM-B romex is a three conductor non-metallic cable. Black, white, and bare ground. The denominator does not include the bare ground. Same convention applies to other NM cables up to at least 6 gauge.

Further, you can certainly use 12/2 for 240 volt circuits that do not need a neutral. Wall heaters are a common 20 amp 240 volt load that uses 12/2 romex.

 

[RickP]

If you definitely want to use recessed lighting, you could probably put all the lights on one or two circuits, depending on the wattage of the bulbs and the number of cans you install. For example, 100 watt bulbs x 24 cans would be a total of 2400 watts, and dividing by 120 volts equals 20 amps. So that would be a good example of when you'd want to use two circuits. But if you use smaller bulbs and fewer cans, you might be able to get by with one circuit -- your choice.

Have you considered using fluorescent fixtures instead? The bulbs last practically forever and they put out a whole lot more light.

Good luck with the install,
Rick

RickP,

What do i need to know to correctly calculate the load draw? I would assume that i need to find the light fixture i am going to use. Assuming that a light fixture for example it would run on 3.0 amps i would be able to put a max of 6 light fixtures on that circuit drawing that would draw 18 amps on a 20 amp circuit is this correct?

 

[bottom feeder]

Perhaps I'm a bit old fashioned in my thinking, and maybe you've already done this, but I would recommend taking a step back and acquire a book (I know, I know, nobody reads actual "books" anymore) containing the fundamentals of how to wire outlets, two-way/three-way/four-way switches, etc. and really study how all this goes together before starting your wiring. Years ago my parents gave me a copy of the Reader's Digest Do It Yourself Manual (still being produced and updated by the way - I checked) that contains an excellent section on home wiring. No doubt the folks on this forum could suggest other, more comprehensive reference sources as well.

Just my $0.02

 

[mechanicworkman]

Great advice guys.

On the GFCI thing, a common method is to use a GFCI plug on the first outlet in a string. Non GFCI outlets are cheap so you start just putting in outlets every 5 feet and next thing you know, you've got 20 outlets downstream of that one GFCI. I don't know if it is a code but I have been warned not to exceed 8 downstream outlets, then another electrician told me 12. Ack

Are you putting a fridge/freezer in the garage? You don't want that plug to be GFCI so be sure that you put it somewhere near the first outlet in the string. I have run into problems where I want a non-GFCI outlet but since I protected the string way upstream, I can't get it.

I have just under 500 feet of 12/2 in my 30x60 so far with about 20% to go. The materials are cheap so go overboard.

Nope no freezer I already have this in my basement on a NON-GFCI protected circuit!

But, in view of keeping the cost down as the GFCI outlets can get expensive and it seems to be code to have the outlets GFCI protected in the garage I will install the GFCI on the first outlet

 

[mechanicworkman]

Do NOT back stab your outlets. Use a pig tail. If you don't know what I mean, look it up or let me know and I'll post a pic for you.

Im not sure exactly what you mean by this are you talking about not using the type of outlet that you just push the wire into the back of it?

When i have bought outlets in the past and installed them i usually get the ones that have the screws that i make the small loop in the end of the wire so that it loops around the screw and tighten down. Is this what you mean.

If a picture is easy enough to come by mabe that would be easier for me to understand exactly!

 

[ez-duzit]

Im not sure exactly what you mean by this are you talking about not using the type of outlet that you just push the wire into the back of it?

When i have bought outlets in the past and installed them i usually get the ones that have the screws that i make the small loop in the end of the wire so that it loops around the screw and tighten down. Is this what you mean.

If a picture is easy enough to come by mabe that would be easier for me to understand exactly!

He means a wiggy.

 

[mechanicworkman]

Have you considered using fluorescent fixtures instead? The bulbs last practically forever and they put out a whole lot more light.

Good luck with the install,
Rick

Rick I seem to have have bad luck with fluorescent lighting seems like an onging problem with the ballast or the 4ft long bulbs. let alone disposing of them in the trash.

This is why i was kinda leading toward recessed lighting is there a better choice other than the 4ft long fluorescent bulb style or the recessed can

My garage is only like 24ft wide by 22 feet deep attached I was hoping that I could get away with only 6-9 of the can style but mabe i am thinking they put out more light than they do i guess

 

[mechanicworkman]

He means a wiggy.

What does this "Wiggy" do and how does it work? now im really confused I thought i knew what he was talking about but now not so sure

 

[ez-duzit]

What does this "Wiggy" do and how does it work? now im really confused I thought i knew what he was talking about but now not so sure

Plug the prongs into an outlet. If there is power, it lights up.

 

[Highbeam]

Plug the prongs into an outlet. If there is power, it lights up.

I don't think that's what anybody was talking about. That wiggy device is for testing for voltage, the pigtail and backstab terms relate to how you attach the outlet to the wire.

 

[ez-duzit]

I don't think that's what anybody was talking about. That wiggy device is for testing for voltage, the pigtail and backstab terms relate to how you attach the outlet to the wire.

Ah, now I see what he meant by don't backstab--not to jumper from the auxiliary wire holes on the back of receptacle (?).

 

[Keyrick]

He means a wiggy.

That is Not a Wiggy. That is a neon test light. A Wiggy, is a solenoid tester, originally manufactured by the Wigginton company, that tests for voltage and applies a small load to the circuit under test.

Backstabing refers to using the small holes in the back of the receptacle to connect your wiring. Most if not all new receptacles will not accept 12 gauge wire, and the connection that is made using this method is not the best. Back Wired receptacles are different as they use the side screws to tighten the conductor to. The method you mentioned, looping around the screw is a good way to go. As was mentioned earlier, pig tailing at some receptacle locations is also recommended.

Rick

 

[ez-duzit]

I've heard these testers referred to as both pigtails and wiggies. And have never heard the term backstabbing used in this context. Sorry for confusing.

Daisy-chaining is another term I've heard for parallel connecting several receptacles.

 

[Keyrick]

No worries! These are Wiggies.

http://www.google.com/imgres?imgurl...zLUcnaDsSarAGYmICQAw&ved=0CFEQ9QEwBg&dur=1841

 

[mechanicworkman]

I got a fluke meter to test if its got voltage

 

[mechanicworkman]

Most if not all new receptacles will not accept 12 gauge wire, and the connection that is made using this method is not the best. Back Wired receptacles are different as they use the side screws to tighten the conductor to. The method you mentioned, looping around the screw is a good way to go. As was mentioned earlier, pig tailing at some receptacle locations is also recommended.

Rick

When you say that the new receptacles won't accept 12 gauge wire are you refering to the ones that use the backstab method or the ones that i loop wire around the screw?

 

[Keyrick]

When you say that the new receptacles won't accept 12 gauge wire are you refering to the ones that use the backstab method or the ones that i loop wire around the screw?

Backstab. The holes are too small, by design, to accept 12 gauge wire. You can loop #12 around the screw without any problem.

 

[ez-duzit]

Yeah, those holes are for jumpering over to the 2nd receptacle in the same dual receptacle box, not for other load distribution.

 

[S1nned]

I think by pigtails he means don't use the outlet as a jumper for the next outlet on the circuit. Pull the wires into the box, and then make a "pigtail" from the outlet to the wires.
Like this:

 

[cdecker]

Perhaps I'm a bit old fashioned in my thinking, and maybe you've already done this, but I would recommend taking a step back and acquire a book (I know, I know, nobody reads actual "books" anymore) containing the fundamentals of how to wire outlets, two-way/three-way/four-way switches, etc. and really study how all this goes together before starting your wiring. Years ago my parents gave me a copy of the Reader's Digest Do It Yourself Manual (still being produced and updated by the way - I checked) that contains an excellent section on home wiring. No doubt the folks on this forum could suggest other, more comprehensive reference sources as well.

Just my $0.02

x2

My parents gave me an earlier version of that same book when I was a teenager back in the 90's. I learned A LOT from it, particularly the wiring sections, but the rest of the book is great as well. Grab yourself a copy, take a little bit of time to lay everything out, decide what you want and where you want it, and implement your plan. This forum is a great source of help when you get stuck.

 

[wyliesdiesels]

Yeah, those holes are for jumpering over to the 2nd receptacle in the same dual receptacle box, not for other load distribution.

Theyre not just for connecting outlets in the same box. Ive seen the backstabbed holes also used to connect to the next outlet 10' away! I wish manufacturers wouldnt put those on outlets. Its such a bad design!

 

[kbs2244]

You need to read this.
A couple of times.

http://www.selfhelpandmore.com/home...o-dwellings/wiring-a-detached-garage-2002.php

My hints.
Use 12 everywhere.
Use ¾ inch conduit everywhere.
Use the “deep” boxes everywhere.

It just makes it a lot easier and the cost increase is not that much.

 

[mechanicworkman]

Ok I got 3 electricians scheduled for Monday to come give me bids on putting in 100 amp sub panel into my attached garage what is a ok rate to have this installed?


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[Rtw5150]

RickP,

What do i need to know to correctly calculate the load draw? I would assume that i need to find the light fixture i am going to use. Assuming that a light fixture for example it would run on 3.0 amps i would be able to put a max of 6 light fixtures on that circuit drawing that would draw 18 amps on a 20 amp circuit is this correct?

You can only run 80% ampacity of your overcurrent device, so 16 amps on a 20A breaker and 12 amps on a 15A breaker.

 

[Rtw5150]

Ok I got 3 electricians scheduled for Monday to come give me bids on putting in 100 amp sub panel into my attached garage what is a ok rate to have this installed?


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I can't tell you what an acceptable rate is since I don't know what labor rates are in your area plus you can only use pipe and wire around here, no romex allowed so it wouldn't be an apples to apples comparison. However I would ask them for a quote on running the lighting and receptacles as well. At the very minimum see if you can get an electrician to inspect everything before you power it up. It only takes one mistake to cause a major catastrophe.

 

[Charles (in GA)]

You can only run 80% ampacity of your overcurrent device, so 16 amps on a 20A breaker and 12 amps on a 15A breaker.

Common incorrect statement. It is ok to load the circut to 100%. If the load exist for over three hours, it becomes continuous and then you get into the 80% restriction. There are other circumstances that limit the load to 80% but this is not a blanket rule and the above statement is incorrect.

12/2 NM-B romex is a three conductor non-metallic cable. Black, white, and bare ground. The denominator does not include the bare ground. Same convention applies to other NM cables up to at least 6 gauge.

This too is an incorrect statement. in CABLE, the gauge is specified by the first number 12, the second number is the number of CONDUCTORS. If there is a ground it is listed as w/grd.

The ground is NOT a CONDUCTOR. A 12/2 w/grd cable has two conductors and a ground.

In CORD, the ground wire is insulated and a cord with a black/white/green is listed as 12/3, and you would not have the w/grd qualifier after it.

Charles

Charles

 

[pattenp]

Oh but, Charles.... the ground is a conductor. It is referred to as a grounded conductor.

Edit: I should add that the second number is the number of insulated conductors.

The ground is NOT a CONDUCTOR. A 12/2 w/grd cable has two conductors and a ground.

Charles

Charles

 

[mechanicworkman]

I got a basic wiring book from Home Depot although its pretty basic but it does go through pig tailing correctly


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