Getting Wiring to Garage

[matt151617]

I'm looking to run wiring out to my detached garage. Someone buried 12/3 Romex directly into the ground/cement, and I'm not sure how much I trust it.

Problem is, there's pavement in the way, and I'm not sure how to get the power wires in. In the first picture, you can see the subpanel in the corner of the garage. In the second picture you can see my meter on the left, the main panel is by this in the basement. And in the third picture, that is the other side of the garage.

The first option I thought of is running conduit from the main panel, through the basement, over to edge of the house near the corner of the garage, into the ground, bending 90 degrees, then across the pavement and into the garage. The other option is to do the same, but go under the deck. The disadvantage of this is having to run conduit over the top of the door to get to the garage subpanel.

 

[pattenp]

The run may be long, but can you come out of the house at the grass area and go through the grass area back into the garage pass that bush and deck on the garage. I wouldn't want to cut up the nice asphalt.

Also transition to SER cable in the house and in the garage that way you don't need to run conduit in the house or garage.

 

[Falcon67]

I think your first option is about it. Wire is expensive so you want to keep it as sort as you can. A big sweep at the run will help in the pull. And don't go small even if pulling low amperage - 1 1/2" at least. Open the ground once.

 

[pattenp]

If you dig a big enough hole on that 90deg turn you may be able to get down to bore under the asphalt.

 

[matt151617]

Unfortunately going under the deck isn't a whole lot easier, there's an old cement walkway under it.

Maybe the best way is to cut a small square where the pavement meets the slab, and bore under the rest of the pavement as mentioned?

 

[dave67fd]

Going under the asphalt isn't as hard as it looks. Most paving companies can repave the small cut-out area and reseal it at a reasonable cost. Something to consider. May save on wire/conduit offsetting the cost.

 

[1967marti]

Chopping up asphalt is easy. Fixing asphault is easy.. Asphault has a natural "healing" ability (if your weather gets warm enough). I'd chop up a strip of it from the house to the garage, shortest run possible... Put in a big pvc pipe (the grey stuff) and run all your wires... Would be a good time to drop a smaller pipe next to it to run your coax and RJ45 cables in. You don't want to run your data cables parallel to power cables... Shield the data cables with metal sheathing if you can or at least run a few bare copper cables tied to the house/earth ground in the same pipe as the data cables...

Dig it up once and put pipes big enough for future expansion...

 

[1967marti]

Almost forgot.... why not run it up and over?

 

[pattenp]

One reason is it would look awful.... well at least to me it would.

Almost forgot.... why not run it up and over?

 

[matt151617]

Going over the top would definitely look bad... plus I'd have to put holes in each roof, and it would require a lot more wire.

What's the easiest way to cut the asphalt?

 

[Aceman]

Going over the top would definitely look bad... plus I'd have to put holes in each roof, and it would require a lot more wire.

What's the easiest way to cut the asphalt?

I'd use a hot saw.

Here's a pic of one:

http://www.stihlusa.com/construction/cutquik.html

 

[pattenp]

I use a circular saw with a diamond blade.

 

[1967marti]

I've ised a pickaxe and one of those big construction crowbars woth great success..... Asphalt doesnt crack like concrete. It comes off in big chips if you hit it at an angle...

 

[71flh]

The romex may actually be UF which is rated for being underground.

Romex is a brand name, but its typically like a tube around the wires, whereas UF is more like the insulated wire running though a flexible plastic rod.

Look at the cable's sheathing and see what it says, and/or check the sheathing where its been stripped to see.

You may not need to change anything...

 

[matt151617]

It's definitely indoor Romex. There's a UF wire right next to it for a feeder line to a light switch in the house.

Besides, it's 12 gauge, so I'm limited to 20 amps.

 

[matt151617]

I'm debating what to do. I will definitely run one 3/4 and one 1.5" conduit from the house to garage. However, from the panel to the edge of the house I have a few options. 2-2-2-4 SER, which is $1.49/ft, but would require transition to another cable type, which a box adds to the cost. 2-2-2-4 URD, which is $1.41/ft, but needs to be in conduit the whole way (much more work, and added cost of $.50/ft for conduit). Or 8 gauge THWN, at a total cost of $1.48/ft for 4 wires, and could be run in cheap 3/4" conduit. The other advantage is being able to use that for the ground rods, saving another ~$20.

I use maybe 15 amps max, and don't plan on ever using more than 40.

 

[pattenp]

If you use #8 for you ground rod conductor it needs to be in RMC, IMC, RTRC, EMT or cable armor. 2011 NEC 250.64 (B). A #6 grounding electrode conductor not subject to damage does not need to be in conduit.

 

[matt151617]

****, maybe I will go with #6 then. What's the best option out of those 3 for running the new wire?

 

[pattenp]

For the power feed where underground from the house to the garage use Sch40 rigid PVC conduit and use Sch80 rigid PVC when above ground where it may be subject to damage.

****, maybe I will go with #6 then. What's the best option out of those 3 for running the new wire?

 

[matt151617]

Should I go with the 2-2-2-4 SER transitioning to URD, 2-2-2-4 URD in conduit all the way, #6 THWN all in conduit, or 6-6-6-8 SER ($.78/ft)?

 

[pattenp]

For my detached garage I fed it 60A. I used 2-2-2-4 AL SER from main-panel to junction box then transitioned to 2-2-2-4 AL MFH (Mobile Home Feeder) in 2" PVC conduit all the way to sub-panel in the detached garage. You could transition back to SER in the garage. It's whether you want to run conduit from panel to panel or use junction boxes and switch to SER when inside so you don't to have to run conduit.

 

[matt151617]

I've gotten pretty far on this project... the ground was soft didn't have tons of rocks so it was pretty easy to dig 18". Tunneling under the pavement was really easy, since they used sand to grade the entire area. I chopped a small hole in the pavement with an old fence post and ran the conduits in.

I'm getting ready to run the wiring... what's the easiest way to transition from the SER to the URD inside the junction box? I'm using 6-6-6-8 SER, and 6-6-6 URD. I'll have to run a separate 8 gauge ground. I could do wirenuts, but I've heard they aren't great with aluminum due to them loosening. Also, I need to join copper and aluminum together, because I don't think I can find a single aluminum THWN.

 

[pattenp]

You say you need to join copper to aluminum. Is one of the #6's aluminum and the other #6 copper. The reason I ask is because #6 AL is good to 50A where as the #6 copper is 65A. So you are limited to 50A because of the aluminum. Edit: Oh I get it now, you're talking about the #8 equipment ground wire will be copper.

You can use these (Splicer/Reducer) with shrink tube to splice your wires in the box. Also use aluminum antioxidant paste on the aluminum wire at connections.

 

[matt151617]

I will join the two hots and the neutrals aluminum to aluminum, 6 gauge. The aluminum ground will be joined to a copper ground, 8 gauge.

I was told I'm limited to 40 amps because SER cable is rated for 60 degrees C.

 

[pattenp]

If the SER is run within thermal insulation such as in a wall then it is to be rated at 60C or 40A. If it's running in open space then you can use it at 75C which is 50A. 2011 NEC 338.10 (B) (4).

I will join the two hots and the neutrals aluminum to aluminum, 6 gauge. The aluminum ground will be joined to a copper ground, 8 gauge.

I was told I'm limited to 40 amps because SER cable is rated for 60 degrees C.

 

[Amazingglazier]

Want a neat cut , use a circular saw with a diamond blade and have a helper with a water hose at a trickle on the blade. Make the first cut at about 1" to score it then recut it full, dig it out run pipe backfill and repair.

 

[matt151617]

Just a couple of notes for anyone else attempting to do this. You'll need to buy some tools if you don't have them. A sledgehammer would be very useful. I got by with a large rock but it wasn't easy. You'll also need a hole saw set. I was going to attempt this with a jigsaw but there was no easy and neat way to do this. Also buy a fish tape for pulling wires, and vice grips to get a grip on the tape when it's slippery. I had more frustration and problems pulling the wires than I did pounding ground rods and digging the trench.

Conduit is cheap but the elbows, fittings, lb's, boxes, etc add up. Home Depot has a nice large 100 amp panel with a main breaker and 5 breakers for $46. I spent about this much on wire. The local electrical supply house was far cheaper on wire. Other supplies ran close to $100.