Simple wiring: detached garage

[AllenB]

First let me just start off by saying I'm an electrical *****. I can run and attach wires etc...but understanding how all that works has escaped me. I just tore down a one car and built a 2 car. The wiring will remain the same with the exception of several more outlets. I tried to diagram it before it was demo'd but looking at it now it makes no sense. I've spent an hour surfing for a simple diagram with no luck. Here is what I had with the old garage and I plan on the same with the new garage:

* I've got 12-3 coming to the garage.
* I'll have one light switch that will operate all the overhead lighting.
* several outlets all unswitched inside the garage.
* 2 outside lights (overhead and entrance door) operated by a switch inside the house.

This can't be that hard...can someone point me to a diagram for dummies?
Thanks!

 

[deter]

Well for starters, where does the 12-3 come from and how is it wired?

 

[VHF]

Were the 2 outside lights also controlled by a switch in the garage (3-way switch), or only at the house?

If only at the house, then the most likley configuration for your 12/3 from the house would be:
• black -- hot for outlets & inside lights
• red -- hot for outside lights switched at house
• white -- neutral
• bare -- ground

 

[AllenB]

Well for starters, where does the 12-3 come from and how is it wired?

Not sure why that matters..nothing has changed on the new garage except for more outlets and an additional outside light. But it comes from a single designated breaker from the main box.

The light over the garage was switched from the inside of the house and not inside the garage.

 

[coolreed]

OMG!!!!

This really scares me. Go get some help from a licensed electrician.

Good Grief

 

[VHF]

The light over the garage was switched from the inside of the house and not inside the garage.

That's good--means there isn't a "farmer's 3-way" circuit here!

The wire breakout I posted earlier is the most likley, although red and black could be flipped. You'll need to use a meter or test light to confirm.

This sounds like a fairly basic garage wiring project, but it has to be done right to avoid shock hazzards or burning down your new garage. It is also a good idea to comply with NEC to ensure insurability and future resale. All recepticles requrie GFCI protection (which can be handled by a single GFCI recepticle protecting the other downstream recepticles.)

Are you wanting some help with the basic wiring layout?

If this is your first wiring project, I would recommend getting a beginners wiring book from The Home Depot or the library and/or finding a knowledgable buddy and/or hiring an electrician to either do the job or guide your work.

 

[BillK]

But it comes from a single designated breaker from the main box.

Is that breaker a single pole or two pole breaker ?

 

[John in OH]

Is that breaker a single pole or two pole breaker ?

Yeah, this is an important question! It will define whether or not that existing 12/3 is 120v or 240v!!!!

 

[deter]

Yeah, this is an important question! It will define whether or not that existing 12/3 is 120v or 240v!!!!

My point exactly. Personally, I think OP should let someone else handle this

 

[BillK]

Yeah, this is an important question! It will define whether or not that existing 12/3 is 120v or 240v!!!!

That was the reason I asked. You would not believe how many DIY's look at 12/2 with ground and call it 12/3

 

[AllenB]

That was the reason I asked. You would not believe how many DIY's look at 12/2 with ground and call it 12/3

It's 12-3 as I initially stated (3 (red, black, white) + ground). It's 110 and not 220. I've got it figured out looking at my initial drawings from the old garage and comparing them with several books (library). What threw me was in my drawings, the light fixture had a black wire coming from it that connected to red coming from the house. From what I read, this is normal. A fixture usually comes with a white and black wire. Red from the house (switched) is designated for the light. Appreciate the help.

 

[BillK]

It's 12-3 as I initially stated (3 (red, black, white) + ground). It's 110 and not 220.

Allen,
Not to argue with you but . . . . you had better make sure of this statemnet. Usually 12-3 with ground is 220, The white wire is neutral and the balack and red are each 110, two different legs. This is why I asked if the breaker is a single pole or 2 pole.

They might be using the extra wire for the switch leg for the light but you really need to be sure.

 

[pattenp]

12-3 provides both 120 and 240.

It's 12-3 as I initially stated (3 (red, black, white) + ground). It's 110 and not 220. I've got it figured out looking at my initial drawings from the old garage and comparing them with several books (library). What threw me was in my drawings, the light fixture had a black wire coming from it that connected to red coming from the house. From what I read, this is normal. A fixture usually comes with a white and black wire. Red from the house (switched) is designated for the light. Appreciate the help.

 

[AllenB]

Allen,
Not to argue with you but . . . . you had better make sure of this statemnet. Usually 12-3 with ground is 220, The white wire is neutral and the balack and red are each 110, two different legs. This is why I asked if the breaker is a single pole or 2 pole.

They might be using the extra wire for the switch leg for the light but you really need to be sure.

I'll double check Bill. But the red powers the switched light on the outside of the building and nothing else. The black powers the inside lights/outlet. The old garage was a small one car with an outside light, and inside light and an outlet for the garage door opener. I don't believe it was 220.

 

[cderalow]

more importantly, if it's detached, how is that 12/3 run? bare in the ground?

 

[BillK]

Allen,
Does the breaker turn off the light also ?

 

[AllenB]

more importantly, if it's detached, how is that 12/3 run? bare in the ground?

1/2 inch conduit.

 

[AllenB]

Allen,
Does the breaker turn off the light also ?

Yes, that breaker turns off both hot wires (outside lights +garaged door opener).

 

[VHF]

Usually 12-3 with ground is 220,

12-3 provides both 120 and 240.

While 12-3 is often used to provide 240V (or both 120V/240V), it is also sometimes used to provide only 120V with both a live hot (for a recepticle) and switched hot (for a light fixture).

In this case, the red wire may be used for the switched hot, which may need to be wire nutted to a black wire in a 12-2 NM cable (Romex) feeding up to an overhead (or outside) light. Sounds like that may be the case here.

 

[skyking]

Best thing I know about electricity is "Beginner or pro ....it will kill you deader than a hammer. GOOD LUCK !