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-   -   Re-running 120 to my garage - want to do it right (http://www.diychatroom.com/f18/re-running-120-my-garage-want-do-right-123632/)

spdorsey 11-16-2011 09:27 AM

Re-running 120 to my garage - want to do it right
 
Hello

When I bought my house, there were 6 copper wires strung in the air between my house and the separated garage. The insulation was cracked and copper was exposed. First thing I did was shut off the main, cut those wires down, and cap the ends.

I want to run 2 x 20 amp lines to my garage underground using conduit. It's about a 20 foot run that goes under a cement path in one spot, and does not run under any auto thruway of any kind (no road or driveway). I have 2 20 amp slots allocated on my breaker panel for the runs, and I can easily string them under my house to the point of exit to the garage.

A few questions:

- If I want to run data lines or phone lines, how far apart does the separate conduit need to be, and can it be above the electrical conduit? (electric is 24" down, can data be 18" in the same trench?)

- Should I install new ground bars and a sub-panel for just 2 circuits? Or is it better just to run romex to a junction box at the point of exit and then single strand in the conduit for the 2 lines?

- Any other suggestions before I get started?

Colomboj 11-16-2011 10:52 AM

- If I want to run data lines or phone lines, how far apart does the separate conduit need to be, and can it be above the electrical conduit? (electric is 24" down, can data be 18" in the same trench?)

As long as you put them in separate conduits you can have them in the same trench.

- Should I install new ground bars and a sub-panel for just 2 circuits? Or is it better just to run romex to a junction box at the point of exit and then single strand in the conduit for the 2 lines?

I would just use a j box. No need for a sub for 2 circuits.

J. V. 11-16-2011 11:22 AM

Good job on removing the existing mess overhead.
But you cannot do what you propose. You cannot run more than one branch circuit or one feeder to any structure on your property.

NEC Article 225.30 States.
II. More Than One Building or Other Structure
225.30 Number of Supplies. Where more than one building
or other structure is on the same property and under
single management, each additional building or other structure
that is served by a branch circuit or feeder on the load
side of the service disconnecting means shall be supplied
by only one feeder or branch circuit unless permitted in
225.30(A) through (E). For the purpose of this section, a
multiwire branch circuit shall be considered a single circuit.

So this leaves you with three options. A feeder and sub panel. A single branch circuit or a MWBC (multiwire branch circuit).
Searching this forum using the keywords I have used will explain each option in detail.

Running data cables between the two structures is a good idea and should be run in the same trench with the power conductors. Conduit for each is the very best way to go.
Research your three options and when you decide which one you will use, we can assist further if required. If you do the research, you will need no more assistance. This subject has been beat to death 100's of times on this forum. Good Luck.

jimmy21 11-16-2011 11:35 AM

Pipe it from your electrical panel into a sub panel. Run individual conductors. You need 2 hot wires. A nuetral and a ground. You also need to drive ground rods. If I was going though the effort, I would run a minimum of #10 and a 1" pvc conduit. Low voltage just needs to be shielded cables but it isn't a bad idea to try to put a little space in between the 2 conduits.

gregzoll 11-16-2011 01:26 PM

If all you are wanting in there is 120v/20a to power a light and a outlet for the garage door opener, you can get away with #12/2. If wanting more, so that you can run a welder, shop tools, etc, then I would look at maybe a 240v/60a circuit. The later will require a sub=panel, the other would not need a sub, since the breaker in the house would serve as the disconnect.

brgmgb 11-16-2011 03:29 PM

I concur with the subpanel option. I would run a larger size wire (#8 or #6) to allow a future upgrade to 30 or even 50 amp service in the garage. Run 240v with three wires plus ground. On the garage subpanel, you can have two circuits (or more if you buy a bigger box). Install the ground rods. Do not bond the neutral to the ground in the subpanel. Of course, use a double breaker in the main box.

I would run a separate conduit for the communication cables, and I would just bury both at 24".

gregzoll 11-16-2011 03:55 PM

They could also use "Octopus" cable for the com. That would give them two data (cat-5e or cat-6), two rg-6, and a cat-3. It would have to be the "flooded" jacketed type for use through the conduit. Reason being, is that moisture would play havoc on the cabling, which can happen in conduits.

http://search.yahoo.com/search;_ylt=...param=&rd=pref

jimmy21 11-16-2011 04:07 PM

Quote:

Originally Posted by gregzoll (Post 772583)
the other would not need a sub, since the breaker in the house would serve as the disconnect.

I think you mean over current protection. The garage would still need a disconnect. The way i do it is mount a 4 square box up high, at say 72" and put a commercial grade 20a light switch in. and label the cover. With it up that high, it won't get confused for a light switch, and if anyone ever wants to put a sub panel in, it gives plenty of room to cut the pipe off and mount a sub panel. Also, if only using #12. Still use 1" so that larger wire could be pulled in later

gregzoll 11-16-2011 04:36 PM

That is how I would do it, keep things simple.

spdorsey 11-18-2011 09:51 AM

J.V. - Thanks for the code snippet - that answers a few questions. I have a clearer idea of what to do. When we bought the house, it had 3 structures in the backyard (the yard is 85' deep), and 2 of them had electric running to them. We tore down all except the garage, but none have elec right now. Perhaps we are grandfathered in because 2 structures had elec before? (just a shot in the dark).

Jimmy and Greg - I'd LOVE to run a 50 amp circuit to the garage, but I'm pushing the service as it is (I have 100 amp service). I just ran wire and new outlets/switches throughout the entire house and rewired much of the breaker box from knob/tube to romex. There is one spot left in the panel, and I can afford a 20/20 double breaker for the garage without overloading the house - just barely.

I may be upgrading my service sometime soon. Ugh!

The garage will be a "man cave" of sorts - containing a computer, TV, fridge, and a small photo studio. I will also use power tools in there, but not very often at all.

The replies are fantastic and very helpful. I appreciate all of them.

AllanJ 11-18-2011 10:19 AM

You can run the #6 wire (for 50 amps) to the garage now and for the time being, power it with the 20/20 double breaker. Later when you or someone else upgrades the main panel and service you can give it the full 50 amps.

gregzoll 11-18-2011 10:37 AM

spdorsey, only would you overload, is if your home is all electric.

HARRY304E 11-18-2011 10:53 AM

Quote:

Originally Posted by spdorsey (Post 773990)
J.V. - Thanks for the code snippet - that answers a few questions. I have a clearer idea of what to do. When we bought the house, it had 3 structures in the backyard (the yard is 85' deep), and 2 of them had electric running to them. We tore down all except the garage, but none have elec right now. Perhaps we are grandfathered in because 2 structures had elec before? (just a shot in the dark).

Jimmy and Greg - I'd LOVE to run a 50 amp circuit to the garage, but I'm pushing the service as it is (I have 100 amp service). I just ran wire and new outlets/switches throughout the entire house and rewired much of the breaker box from knob/tube to romex. There is one spot left in the panel, and I can afford a 20/20 double breaker for the garage without overloading the house - just barely.

I may be upgrading my service sometime soon. Ugh!

The garage will be a "man cave" of sorts - containing a computer, TV, fridge, and a small photo studio. I will also use power tools in there, but not very often at all.

The replies are fantastic and very helpful. I appreciate all of them.

Run 2 ,1-1'4" PVC to the garage run 4 #10 conductors use a twp pole 30 amp breaker in your house panel to feed your sub panel.

Use another two pole breaker in the sub panel that will be your disconnect in the garage.

Drive two 5/8th's ground rods and run #6 copper to the ground rods from your sub panel.

The load you just described will never trip that breaker unless you are using Electric heat in there.

the large pipes will allow you to upgrade later on

spdorsey 11-18-2011 10:59 AM

I'll hopefully never need heat in there, as we plan to insulate the garage before we finish the walls. I could always have a gas line run out back, it wouldn't cost much considering the savings and convenience.

jimmy21 11-18-2011 11:08 AM

I would still take 60 amps to the garage. Just because you have the available power out there doesn't mean you are overloading the service. It makes it nice that the lights won't dim everytime your refrigerator kick on. Which they likely would if you only ran #12


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