Running Electricity Outside

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  #1  
Old 04-14-13, 12:05 PM
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Running Electricity Outside

Hey guys. I posted a thread a while back asking about an outdoor theater. I'm pretty well set on what materials I'll be getting. Now, I need to figure out how to get power out back in the yard to run the projector, dvd player, speakers, etc. I've got a line running out to my garage. I was hoping I could piggy back off of that and run that out back about 350'. So, here's my question: The line running out to my garage comes out from my basement, about 2' above ground, and then goes under ground to my garage and up to a box in the garage.

Would it be best to put in a junction box where the wires come out of the house, and then run it out back from there, or to tie into the box in the garage, and run it out back from there? Also, when I was looking up 12-3 UF wire, I saw that 250' was about $180, whereas the next size up, 500', was nearly $500. I figured it would make more sense to buy a couple rolls of 250', or a 250' and a 100', and just bring the wire above ground wherever it ends, and junction it off to the next length of wire to go the rest of the way.

Also, regardless of which route I take, can you recommend parts (outdoor junction boxes, outdoor 4-way outlet) that I would need to accomplish this?
 
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  #2  
Old 04-14-13, 12:22 PM
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You're talking about a LOT of wire. 12-3 is only going to be adequate since you can bring out two circuits.

Personally, I would lean towards 10 gauge wire in PVC pipe.

Something is wrong with those wire prices. Difference between 250' and 500' should be within 10.00 dollars or so. You were either looking at two different gauges or the wire length was mis-marked.

How are you running it underground ? Trenching .... vibrating plow ... etc. ?
 
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Old 04-14-13, 12:26 PM
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I think PJ is spot on with his info, but we could dial it in a little better if we knew what the load will be on the end of the 350' run. Add up the watts of everything you are planning on using at your theater.
 
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Old 04-14-13, 01:35 PM
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There are actually 2 wires going out to the garage, in order to run a 240v Air compressor, so I could run both out if needed. The 250' wire price is what I found on Home Depot's site: Southwire 250 ft. 12-3 UF-B W/G Cable-13058355 at The Home Depot
I couldn't find 500' wire at Home Depot or Lowes or anywhere else near me. I only found some on ebay: 500' 12 3 uf Cable uf B 12 3 WG Wire Direct Burial CU | eBay

As far as burying goes, I planned on doing a lot of digging with a shovel.

At the end of the wire... I'll be using these speakers: Amazon.com: Behringer TRUTH B2031A Active 2-Way Reference Studio Monitor Pair: Musical Instruments (Behringer B2031A) I don't know the exact wattage. Amazon says "Built-in 150- and 75-Watt power amps with enormous power reserve."
The projector is this one: Amazon.com: ViewSonic PRO8200 1080p DLP Home Theater Projector: Electronics (ViewSonic Pro8200) Again, not sure on total wattage.. I know the speakers are 2x10w, and the lamp is 230w. The DVD player will probably be this one: Amazon.com: Sony BDP-S390 Blu-ray Disc Player with Wi-Fi (Black): Electronics
 
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Old 04-14-13, 01:54 PM
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Ok well, it appears that you will not be running too much, although I think you forgot a few things, such as an amp to run the speakers. Projector is 310 watts and Blu Ray will be very small load. (100 watts maybe)

I would not use UF cable due to length limitations, and/or cost. I suggest running 3/4" - 1" PVC conduit and pull in 4 #10 wires. You could run #12's, but why risk it with your expensive electronics? Two hots, one neutral and a ground. THHN/THWN comes in 500' rolls and be sure to buy stranded. That will give you 2 - 120 volt circuits in case you want to add a popcorn maker.

You may also want to consider dropping in another conduit in the same trench to run low voltage CAT5 for phone, internet, or network. You could then run movies off a media center computer on your home network. Also, PVC you only need to dig down 18", UF needs to be 24" down

At 350', I would suggest renting a trencher.
 
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Old 04-14-13, 02:05 PM
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At 350', I would suggest renting a trencher.
That's the best suggestion yet! I can't even imagine digging a ditch 24" deep X 350 feet long.
 
  #7  
Old 04-14-13, 03:06 PM
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There are actually 2 wires going out to the garage, in order to run a 240v Air compressor, so I could run both out if needed.
What size are those wires and what size is the breaker protecting them?

The voltage drop calculator at Southwire recommended using #3 AWG copper conductors to limit the voltage drop to less than 3% on a 350' run for 20A circuits.
 
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Old 04-14-13, 03:22 PM
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Voltage drop depends on the load at the end of the run, not the breaker rateing. It sounds like his load will be less than 1000 watts or so.
 
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Old 04-14-13, 04:45 PM
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I have no idea how Southwire thought they could come up with that value with no load put into the calculation. Scratch that link off my list!

Edit: I did it wrong. They do have the load built in, and for some reason I was putting in 20A at the end of the run. Looking for 9 amps there, for 1000W, gets the wire size down to #6. 5 amps takes it to #8 conductors. For 310W plus 100W, or 3.5 A, you can use #10.

The calculator is okay. Just operator error.
 

Last edited by Nashkat1; 04-14-13 at 05:35 PM.
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Old 04-14-13, 05:15 PM
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You may also want to consider dropping in another conduit in the same trench to run low voltage CAT5 for phone, internet, or network.
Ethernet (Internet or network) is limited to 100 meters or about 328 feet between powered nodes. For a 350 foot (plus inside to connection node) you would almost have to use fiber optic cable.
 
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Old 04-15-13, 04:35 AM
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Yes. You can use two blacks instead of red and black if you want.
 
  #13  
Old 04-15-13, 06:09 AM
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The total max is 6.7A:
[table="width: 500, class: grid"]
[tr][td]Amps[/td]
[td]Reference[/td]
[/tr]Behringer TRUTH B2031A (pair)
[tr]
[td]4.0[/td]
[td]Per http://www.behringer.com/assets/B2030A_P0135_M_EN.pdf, pg 10: 2A max each[/td]
[/tr]
[tr][td]2.6[/td]
[td]Per http://www1.viewsonic.com/assets/103/20615.pdf, pg 2: 310W max[/td]
[/tr]
[tr][td]0.1[/td]
[td]Per Sony Blu-ray Disc Player |Sony Streaming Player with Wi-Fi | BDP-S390 | Sony USA[/td]
[/tr]
[tr]
[td]=====[/td]
[td][/td]
[/tr]
[tr][td]6.7[/td]
[td][/td]
[/tr]
[/table]

It sounds like the wire cost is significant. I'm not an electrician, so this suggestion might not be legit under code, but in situations like this can you take the 240 and use a 120 / 240 transformer to step the voltage down at the end? That way, smaller gauge wire could be used because it would only carry about 3.5A.

Even if it is OK under code (and I have no clue), in this case it is probably not worth it because I think a 1000W transformer would be around $100. (FRYS.com|100W Tek-Mate Transformer)

Re Cat-5: it is not like a 328' is fine and a 350' run would fail; signal degradation is a gradual thing. The chances are still pretty good it would work. HOWEVER: if you decide to run a 2nd conduit in the trench, be sure to keep them separated by at LEAST 1', more if possible! The parallel AC run will induce interference in the Cat-5, so even if the run length is OK it might still fail.
 

Last edited by parkerea; 04-15-13 at 06:56 AM. Reason: Correction & add CAT-5 comment
  #14  
Old 04-15-13, 11:43 AM
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Ok. So, will this work?
Maybe. You need to figure your total load carefully. #10 is good for up to a little less than 5 amps with less than 3% voltage drop on a 350' pull. Above that you'll need to pull #8. Be sure the wire is designated THWN as well as THHN.

Why are you buying your materials at a home improvement store? Is there no electrical supply house near you?
 
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Old 04-15-13, 11:46 AM
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I wonder if #6 aluminum quadplex mobile home cable wouldn't be a better choice if they make it that small. What do you say pros? Maybe lower cost and plenty of capacity.
 
  #16  
Old 04-15-13, 04:44 PM
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Here is the amp I'll be using: Dayton Audio DTA-100a Class-T Digital Amplifier 50 WPC Provides Power To Computer Speakers, Bookshelf Speakers, Headphones, And More! 300-383
It's a 50w. So, all in all, I'll be running the projector, the amp, the speakers, and the Blu-Ray player.

The only electrical supply near me is Grainger, and their prices are way higher than Lowes.
 

Last edited by Jephph; 04-15-13 at 07:07 PM. Reason: typo
  #17  
Old 04-15-13, 06:44 PM
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I just bought some rolls of #10 THHN at our supplier for just under $100 so Lowe's is not too far off.

That transformer would not help because he is already running 120/240 volts out there with the two circuits.

Just an FYI - Keeping voltage drop less that 3% is not a code requirement, as it is in the NEC as an informational note. It still might be a good idea to keep it low so not burning up the equipment due to under voltage, but with two circuits, you can split the load in half. Also, a lot of electronic has quite the wide range of voltage they can handle.

Lastly, according to my calculations (or Southwire's ) he can have about 10 amps (2400 watts) total, divided between the two circuits at the end of the run, and the voltage drop would still be only 2.76% on #10 copper.
A maximum distance of 343.076 feet will limit the voltage drop to 3% or less with a #10 Copper conductor delivering 10.0 amps on a 240 volt system.
I can't comment on the #6 cable as I have never priced it. =\
 
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Old 04-15-13, 06:55 PM
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I just noticed that those wires I posted from Lowes don't specify THWN. Should I get different wire?
 
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Old 04-15-13, 07:03 PM
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I have never seen THHN wire that is not also rated THWN (among other ratings) Just to be safe, look on the wire and you will see the listing printed on the insulation.
 
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Old 04-15-13, 07:06 PM
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Thank you.

Also, I have no idea where the neutral wire should go. And, can you point me to a 4 outlet box that I can run these to and use outside?
 
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Old 04-15-13, 07:14 PM
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Looks like you can get it for $10 less a roll at Big Orange: Southwire 500 ft. 10 Stranded THHN Blue Wire-22976557 at The Home Depot They also have a bulk discount for 2 or more rolls.

The neutral wire will go to the sliver screws of the two duplex receptacles. You can use any 2 gang weather proof box with 1" holes (to match your 1" conduit) Greenfield 2 Gang Weatherproof Deep Electric Outlet Box with Five 1 in. Holes - Gray-DB452PS at The Home Depot
You will also need a two gang in use cover: Red Dot 2-Gang Extra Duty Non-Metallic While-in-Use Weatherproof Receptacle Cover - Clear 2 7/8 in. Deep-2CKPM at The Home Depot
And of course, two GFCI receptacles.

Items is for reference only, You should be find the same stuff at Lowes or any hardware store.
 
  #22  
Old 04-17-13, 03:30 AM
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Where does the neutral go on the other end?
 
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Old 04-17-13, 06:11 AM
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Where does the neutral go on the other end?
It goes to the neutral bar at the house. At the receptacle it goes to the neutral on the line side of the GFCI receptacle. The non GFCI receptacle's silver screw is connected by a short white wire to the load side silver screw of the GFCI. Both receptacles should be rated for outdoor use.
 
  #24  
Old 04-23-13, 03:08 PM
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Where the wire enters the garage from underground through the concrete, should I seal it off so that no water enters the conduit? Also, should I put some sort of sleeve around the 4 wires as they run up to the junction box?
 
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Old 04-23-13, 04:14 PM
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The conduit must extend to the box.
 
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Old 04-23-13, 04:19 PM
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Hmm. Well then... Can I come above ground, and then enter the garage through the wall? I certainly don't have the means to drill a 1 1/4 hole through the concrete floor.
 
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Old 04-23-13, 04:28 PM
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Can I come above ground, and then enter the garage through the wall?
In conduit? You should be able to. Schedule 80 PVC or rigid metal should be acceptable above ground, but check with your inspector.
 
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Old 04-23-13, 04:54 PM
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Thank you.

How do I seal the spot where the conduit meets the box?
 
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Old 04-23-13, 06:35 PM
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How do I seal the spot where the conduit meets the box?
The conduit is inserted into a PVC adapter inserted into the box and held with nuts.

[ATTACH=CONFIG]11865[/ATTACH]
 
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Old 04-23-13, 06:51 PM
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Water will get into any conduit outside or underground. This is why the conductors need to be rated for a wet environment.
 
  #31  
Old 04-23-13, 10:14 PM
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How do I seal the spot where the conduit meets the box?
Seal it against what? Seal inside it or seal around it?

Conduit is sealed on the inside when it is installed where temperature differences, a flammable environment or other special conditions require it. It is sealed around the outside to prevent water from entering outdoor enclosures.

You don't seem to have these conditions.
 
  #32  
Old 05-11-13, 09:11 AM
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Since both receptacles will receive their own separate hot wires, how do you run the ground and nuetral wires? Do I run the neutral from the "line" on the first receptacle to the "line" on the end receptacle, or from the "load" on the first receptacle to the "line" on the end receptacle?
 
  #33  
Old 05-11-13, 01:26 PM
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Best thing to so is take a short piece of wire (pigtail), white for neutral, bare or green for ground. Attach one each to each receptacle. Then splice the 3 whites together, and the three grounds together. Everything on the line of the GFCI.
 
  #34  
Old 05-11-13, 04:06 PM
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Since both receptacles will receive their own separate hot wires, how do you run the ground and nuetral wires? Do I run the neutral from the "line" on the first receptacle to the "line" on the end receptacle, or from the "load" on the first receptacle to the "line" on the end receptacle?
I'm not sure I understand your question. Are you running a multiwire branch circuit - two hot wires and one shared neutral for two 120V circuits?

If so, you need two GFCI receptacles. One of the hot wires gets connected to the brass LINE terminal on each of those receptacles. The shared neutral gets spliced to two pieces of white wire and one of those two pieces gets connected to the silver LINE terminal on each receptacle.

Any additional receptacles are wired with conductors that are connected to the LOAD terminals on one or the other GFCI receptacle. Any loads that don't require GFCI protection, such as lighting, can be fed with wires connected to the LINE terminals next to the wires coming from the panel.

Ground is ground. Splice them all together in each box and add pigtails to bond the box, if it's metal, and all of the devices mounted in it.
 
  #35  
Old 05-14-13, 05:34 PM
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This stranded 10 AWG is pretty thick for these receptacle screws. Can I use a smaller gauge for just the pigtails? Or would it be better to get some solid 10 AWG and use that for the pigtails?
 
  #36  
Old 05-14-13, 05:48 PM
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This stranded 10 AWG is pretty thick for these receptacle screws.
Use back wired commercial grade receptacles.

 
  #37  
Old 05-14-13, 05:55 PM
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Most if the GFCI receptacles I install lately all have back wired holes. I use Pass and Seymour devices.

Since you are using a 20 amp breaker it would also be acceptable to put #12 pigtails on the devices and splice to the #10 wire.
 
  #38  
Old 05-14-13, 06:04 PM
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Touché.
I saw those holes the other day. For some reason, I didn't notice them at all the whole time I was struggling to wire them today. Once again, thanks guys. And boy, you are speedy.
 
  #39  
Old 05-15-13, 01:55 PM
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Just noticed there's no hole for the ground wire. Can I run 12 AWG for that?

EDIT: Nevermind. I just noticed the clamp under the screw. That's handy.
 
  #40  
Old 05-15-13, 02:01 PM
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Just noticed there's no hole for the ground wire. Can I run 12 AWG for that?
If it's a 20A circuit then yes. Green-insulated 12 AWG.
 
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