Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 02-22-2012, 10:17 AM   #1
Member
 
Join Date: Feb 2012
Posts: 178
Share |
Default

MWBC to Garage Questions


Hey all, long time lurker, first time poster here.

I'm in the planning stages of running a circuit to my small garage and just want to make sure all of my research has instilled in me an understanding of how to do this.

The plan:

200 Amp service in Main Panel at house. Install Double Pole 20 Amp breaker in Main from there use 12/3 UF-B through 20 feet of basement, out back of house into 18-24 inch trench underground to garage about 30 feet away. I plan to use 3/4" or 1" conduit for the whole run in case I later want to upgrade, but at this point I think a 20 Amp MWBC is more than enough for the few lights and receptacles I need. In same trench I'm going to have another 1/2" conduit to run coax cable and Ethernet to the garage.

Once the 12/3 enters the garage I will keep it in conduit to a double pole switch box for a disconnect. In the box I will join neutrals of (2) 12/2 cables and the neutral of the 12/3. I will then connect the red and black of the 12/3 to the switch, and the blacks from the 12/2s to the switch. One 12/2 will go to a tamper-resistant GFCI outlet and continue with 12/2 on the load side for additional non-GFCI outlets (but GFCI protected of course) (probably 6-8 outlets around perimeter of garage and one exterior outlet on side of garage). Also, I will make sure all neutrals are pigtailed. The second 12/2 will supply power to lights. I may install one GFCI outlet prior to the lights just in case I have the other branch of the circuit loaded up at some point. It will power approximately 2 switched lights inside and another 2-4 lights outside of garage.

I also want to have a three way switch for one or more of the outside lights so they can be turned on or off from both the garage and the kitchen in the house. Is the correct way to do this to power the lights from the garage's MWBC as described above, then from the light(s) to a three-way switch in the garage and then from that switch run 12/3 back to the house to the three-way switch in the house? Can this be run in and out of the same conduit as the MWBC?

Does all of this sound right? Also the reason I am doing this and not a sub panel is a) I don't think I will ever need that much power out in the garage and b) I want to save some money.

Thanks for any help,

Ben


Last edited by benleef; 02-22-2012 at 10:27 AM.
benleef is offline   Reply With Quote
Old 02-22-2012, 10:31 AM   #2
Licensed electrician
 
Join Date: Sep 2007
Location: Maryland
Posts: 7,397
Default

MWBC to Garage Questions


It will be much easier to pull individual conductors into the conduit over the UF cable.

__________________
Answers based on the National Electrical Code. Local amendments may apply. Check with your local building officials.
Jim Port is offline   Reply With Quote
Old 02-22-2012, 10:54 AM   #3
Member
 
rditz's Avatar
 
Join Date: Jan 2011
Location: Lindsay, Ontario, Canada
Posts: 271
Default

MWBC to Garage Questions


i would put a small pony panel in the garage. this way you can turn off individual circuits while keeping others turned on...

it is also a good way to organize your circuits.. it also allows you to have a mix of 120VAC and 240VAC circuits...
rditz is offline   Reply With Quote
Old 02-22-2012, 11:02 AM   #4
Member
 
Join Date: Feb 2012
Posts: 178
Default

MWBC to Garage Questions


Also, I'm open to running 8/3 with 40 Amp Double Pole Breaker in Main to Garage Main Lug Sub Panel in garage. I figure this would maybe increase the cost by about $150-$200 for bigger wires, bigger and more breakers, sub panel, and ground rods. But I'm willing to spend the extra $ if it will be safer and easier.

If I do this, my ground from the sub would have to run along the length of the garage to the back where I could insert ground rods (concrete in the way otherwise on outside). Does the bare copper ground have to be run in conduit along the garage? Or just through holes in studs OK?

Also, what about 12/3 or 14/3 back to house for three-way switch? Can this be in same conduit as feeder cable?
benleef is offline   Reply With Quote
Reply

Tags
garage, mwbc


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
In theory: expand attached garage, or add detached garage? hyunelan2 Building & Construction 5 11-09-2012 05:34 PM
Expanding Garage INTO house (goodbye Den) texaopian Building & Construction 16 11-07-2011 10:32 PM
reroofing garage - a few questions wombosi Roofing/Siding 10 06-29-2009 09:57 AM
Garage foundation questions Don-NH Building & Construction 2 04-16-2005 12:03 AM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.