Need help planning an electrical service upgrade to detached garage

PaulTurner · 04-05-2011, 11:28 AM

Hi, y'all,

First off, I have read a lot of threads on this site about running electricity to a detached garage. I also thought this pdf file from Bloomington, Minn. was very helpful: http://www.ci.bloomington.mn.us/hand...3fffdetach.pdf

I need to run RG6UQ for some HD antennas back to my house from a detached garage. Since I have to dig a trench, I may as well lay conduit for a future electrical upgrade.

The house and detached garage were built around 1915. The existing underground cable is something no longer made today. It's only two conductors, very light gauge, and visibly deteriorated. The cable is in a conduit with a very small I.D. and is also visibly deteriorated. So, I don't want to reuse the conduit.

(1) As I understand things, my choices are direct burial at 24 inches; or PVC conduit at 18 inches; or rigid or intermediate conduit at 6 inches. The distance is only about 25 feet. But for the last 10 feet, I'll be digging on my hands and knees under my deck. So I'm thinking that the 6 inch option is the least of the evils. I've never run conduit before, so how would you do it?

(2) Immediately after it enters my house's basement, the old wire enters a box and is spliced to modern Romex. I read somewhere that no splices are allowed between the subpanel in a detached garage and the main panel in the house basement. Is this correct?

(3) Does the subpanel in the garage have to mounted at any particular height? Is there a maximum or a minimum? I've never seen anything about this.

(4) As for the RG6UQ, I know it needs its own conduit. It's only going to be carrying a few millivolts from the antennas. Is there any particular conduit I have to use for this? If not, I'd just as soon use a length of heavy duty garden hose running all the way from the interior of the garage to the interior of the basement. The hose is waterproof by definition and would provide as much protection from accidental damage as I really need.

Thanks in advance to all,
Paul

joed · 04-05-2011, 11:56 AM

1. You could run it along the underside of the deck and go underground at the edge of the deck.
2. Not true. Splices are fine if imade in a proper accessible box.
3. Same as any other sub panel. Maximum height of highest breaker is 6'7". Standard clearances are also required.30 x 36.
4. I don't believe conduit is REQUIRED. I don't like the garden hose idea however. No underground conduit is ever dry. They all fill with water from condensation.

PaulTurner · 04-05-2011, 04:43 PM

Joe,

Thank you for such a quick reply. I've got a few follow up questions.

(1) I see you've got a ton of posts here, some 3,200 to my one. Where do you get your knowledge from?

(2) I really like your tip about running the cable along the underside of the deck. Are you sure that this practice is the same in the U.S. as in Canada?

(3) Running from the edge of the deck to the garage, do you have a preference for type or brand of conduit?

(4) You mention standard clearances for the subpanel. I didn't follow you here.

(5) I've got an unused 220v outlet near the location where the electrical cable from the garage enters the house's basement. It was for an electric clothes dryer before I had natural gas run into the house. The 220v outlet is on a dedicated circuit and isn't going to get reused in the future.

What do you think about replacing the 220v outlet with a box and splicing in a cable out to a main breaker subpanel in the garage? I don't need 220v service at present, but it could be handy someday.