What wire to run in an underground conduit?
orourke
14 years ago
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orourke
14 years agolast modified: 9 years agoRelated Discussions
Underground plastic conduit
Comments (13)word of warning onthe shed project, run 2 conduits and either seperate them in different trenches or at least put the conduit with teh telco/network/TV feeds 12" higher up inthe same trench. that long a run you WILL get voltage induce onthe lines otherwise. best case scenario is it creates a noticeable hum, worst case it can induce enough to damage equipment. you want the conduits 12-18" apart MINIMUM, so either 2 trenches, or one trench wide or deep enough to get this seperation. i always run the AC on the bottom of the trench, then at both ends have the upper conduit turn to one side and come up so they don't rise together. it is a pain in the butt to have to dig it back up cause the auido/video lines are unusable. a local sheriff's dept here ran power and telco line to their RF shack at their tower inthe same trench after we told them not to do it. we went to hook it up to the radios, and guess what not a single pair out of the 100 pair cable was usuable due to induced voltage. they had to pull the 100 pair cable back out the conduit and trench in a new one a couple feet over....See Moreunderground wiring
Comments (12)The ampacities have above have nothing to do with distance. It's the standard capacity for 90C wiring derated due to having more than three current carrying conductors in the conduit. The amount of load you can run depends on how much voltage drop you can tolerate in the barn. Since it seems that the wire size is fixed, it doesn't seem like it matters. You still use a 60A breaker. To compute the voltage drop you'll need the ACTUAL load drawn and the distance (and the #6) wire size. You can google to find several calculators that will let you know what kind of drop you're looking at....See MoreWhat's proper wire to run in exterior conduit?
Comments (1)Single THWN wires commonly known as THHN/THWN. Have to buy separate colors, green, white, and black or other colors for additional hot conductors. You could use UF cable (the gray romex like cable that is rated for underground) but it is only allowed in short lengths of conduit for physical protection....See MoreCan I run romex through buried conduit from garage to house?
Comments (27)I've only looked into flying feeders a bit, but I don't think that any kind of cable (including sunlight resistant UF) is approved for flying overhead by itself. It might be OK if you used an approved messenger cable to support it. Others may know more about that. I do know that it has to be at least 10' above ground at every point, 12' over the driveway. Keep in mind that your feeder will sag some in hot weather. Overhead wiring to an outbuilding used to be pretty common, especially on farms. Today I don't see any advantage to it. IMO, burial is better in every way, including appearance and lightning protection. Others may have different opinions. For a multiwire circuit, you need a double pole breaker, not two separate breakers. For 12" buried UF, it would have to be a 20 amp double pole GFI breaker. Make sure you're sitting down when you look at the price for it. OTOH, burial that shallow might mean that you could trench with a shovel and avoid trencher rental or contract expense. Trench to 24" and you don't need the GFI breaker, but you'll still need GFI protection in the garage. Don't forget to screen the backfill. Rocks will damage your cable as the ground shifts and heaves with frost. I say bite the bullet and use AWG 12 for your lighting circuit. It's not that much harder to work with....See Morebryanlm
14 years agolast modified: 9 years agoRon Natalie
14 years agobrickeyee
14 years agolast modified: 9 years agojmvd20
14 years agolast modified: 9 years agoRon Natalie
14 years agogblentz
14 years agolast modified: 9 years agoterribletom
14 years agolast modified: 9 years agobuckeyeinwi
14 years agolast modified: 9 years agojmvd20
14 years agolast modified: 9 years agopetey_racer
14 years agolast modified: 9 years agoorourke
14 years agolast modified: 9 years agoRon Natalie
14 years agojmvd20
14 years agolast modified: 9 years agojmvd20
14 years agolast modified: 9 years agoterribletom
14 years agolast modified: 9 years agoorourke
14 years agolast modified: 9 years agoRon Natalie
14 years agoterribletom
14 years agolast modified: 9 years agoorourke
14 years agolast modified: 9 years agoRon Natalie
14 years ago
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