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Elegant_Schedule1566 OP t1_j05h7u3 wrote

Reply to comment by anothervtcouple in How much did it cost you to run power to your build per foot/yard? Green Mountain Power by Elegant_Schedule1566

At what depth does the conduit/trenched cables need to be? I think someone gave me a link to a handbook below but figured I’d ask in case you knew off the top of your head. We’d probably do this part ourselves.

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Willie_the_Wombat t1_j05s17q wrote

Most utility providers will require their primary conduits to have 36” of cover. If it’s not practical to achieve that depth, you could potentially work out a contingency with concrete encasement.

Edit: “primary” meaning from the last utility pole to the transformer location. From the transformer to the meter location and/or entrance of the structure is considered the “secondary”. In most cases secondary conduit will require 18-24” of cover, depending on material and use.

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Elegant_Schedule1566 OP t1_j0626xh wrote

Awesome, thanks so much for the info. Do you know anything about crossing small streams with cable? I get that water and electrical doesn’t mix, but considering there’s so much water in VT I’m wondering if anyone’s figured out how to make crossing a small stream feasible with underground conduit, like placing it over or below a culvert or bridge or something, or if that scenario will always require overhead lines whether related to permitting or code.

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Loosh_03062 t1_j06g3n9 wrote

Crossing the streams? Forget calling the Ghostbusters, you'll be talking to the Agency of Natural Resources. They can be persnickety at times.

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happyonthehill802 t1_j06ie9m wrote

Chances of legally touching a stream with a piece of equipment are not good.

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[deleted] t1_j06jkn8 wrote

[deleted]

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Legitimate-Future255 t1_j06onqf wrote

What they are trying to say here is the agency of natural resources in Vermont is VERY strict about any work done near water, on public or private land and the red tape/permitting/cost of trying to “touch” the stream will far outweigh the cost of going overhead instead

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Willie_the_Wombat t1_j06tqu2 wrote

That really depends on what you mean when you say “stream”. If it’s small enough that your driveway would cross it using a culvert, you would just continue the conduit underneath. If it’s big enough to require a bridge for the driveway, you’d probably surface the conduit on both sides and attach to the bridge.

As for the state getting involved, I believe that depends on the size of the watershed being collected. But I don’t know the exact regulations, or dimensions.

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Elegant_Schedule1566 OP t1_j06uroj wrote

Oh that totally makes sense, I didn’t think of it running along a bridge - have you seen that done before or done it? Either scenarios are possible options in my run, so that’s at least a good starting place to look into doing. Thanks so much for the helpful info.

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Willie_the_Wombat t1_j06wu6f wrote

Yes, back when I was an apprentice. We attached conduit to the bottom of a covered bridge at a winery.

You (or your contractor) will be responsible for installation of the primary conduit run in whatever path it takes. But your utility (GMP or others) will design that installation for you. Primary (before the final transformer) is outside the jurisdiction of the NEC and local inspectors if applicable. The utility will specify what conduit(s), cover, attachments, etc… for you depending on the particulars of your project.

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KittenLOVER999 t1_j06t8qy wrote

Also make sure you use the right diameter…at least at the pole, not going to suggest or say I’ve stepped down to smaller under ground…but hey it’s buried only you will know

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Elegant_Schedule1566 OP t1_j06udoc wrote

You mean diameter of conduit? What are typical, appropriate diameters?

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happyonthehill802 t1_j06z9ej wrote

Conduit size depends on wire guage. Wire guage depends on run length and amperage required.

I personally wouldnt skimp on conduit size...infact on smaller runs i often upsize. You'll thank yourself if you ever need to replace/upgrade the cable.

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KittenLOVER999 t1_j073zwe wrote

Not sure if it depends on your provider as well or not but Comcast is 4 inch (completely unnecessary IMO), Washington electric was also 4 inch

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jaylaxel t1_j07ehh8 wrote

GMP doesn't want to deal with anything less than 4", but other comms routinely use 2" for cable or fiber, and yes, they are supposed to be separate conduits (for commercial work at least)

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