Rural service installation

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  #1  
Old 02-02-15, 08:10 AM
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Rural service installation

This is for a rural property, no permits or inspections are required. I just bought a used trencher and would like to install electrical service between the poles and buildings myself. The actual "inside the box work" would be left to an electrician. We're not opposed to having our service provider upgrade our incoming power.

Want to go direct burial, 18" down, leaving several feet of slack at each end.
I have an account with a local electrical supplier as I play a low voltage contractor during the week

What size wire would I need to each?

Blue is the existing service (toned pathway), red is what I need added. Not opposed to re-running a larger feed between pole 1 and pole 2. Here's what we want to power up.


Gate: sliding gate, lights, and once a year, Christmas lights

Tool Shed: lights, fan, feed to future 50x40 shop.

Shop: maybe some light wood working, sanders, lighting, large fans, ac unit for an enclosed storage area (paper goods, etc.)

Light/fan (2): two lights and one fan

Cabin 1: lights, fridge, freezer, small ac unit, fan

Cabin 2: 220 ac unit, fridge, freezer, washer/dryer, water heater, stove, septic unit, lights, fans, 1000w computers (2),

3rd pole (concrete patio): three ceiling fans, lights


No pics of box inside of cabin 1





Pole 1




Pole 2






Pole 3

 
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  #2  
Old 02-02-15, 08:31 AM
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You have several issues with the existing setup.

The neutral is not identified and the use of a plumbing 90 is incorrect.

In this one:
You have a white on the feed through lug that should be re-identified as a hot. It also looks like there is no neutral to whatever that cable feeds. The wire may also be too small for the lugs.

In this one:

The lugs should only have one conductor in them. The neutral and grounds need to be separated and a ground bar installed. Also the neutral in the cable is undersized since both breaker are now on the same leg.

The smallest service allowed to a dwelling by the NEC is a 100 amps. The feeder to the shop is based on the expected loads.
 
  #3  
Old 02-02-15, 08:48 AM
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In this case I would probably look at just buying some bulk 4 conductor underground feeder cable like #2 MHF (mobile home feeder) and laying that in all the trenches. It can supply up to 90A which is perhaps an overkill on things like the gate, but gives you flexibility on future use and simplified materials. The direct burial aluminum won't be any more expensive than a smaller copper cable like UF-B.

Direct burial cables needs to be 24" deep minimum to the top of the cable, so 26" or so deep on the trencher.

All of your outbuildings should have 4 wire feeders with separate ground and neutral.

Why are two feeds marked for the tool shed on your diagram?
 
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Old 02-02-15, 08:52 AM
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Aww crap, messed up that drawing.

The 2nd red line to the shed is 120' and should have been a different color just for reference.

All the work you see was existing when I bought the place. Going 24" wouldn't be a problem.
 
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Old 02-02-15, 09:09 AM
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Conduit can go 18" but best practice should be individual conductors in conduit. Ask your electrician what he wants.
 
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Old 02-02-15, 09:15 AM
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All the work you see was existing when I bought the place.
And it's a mess. Best to just disconnect it all and start over.
 
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Old 02-02-15, 09:23 AM
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Certainly not opposed to that, CasualJoe!

Ray, what size conduits would you install? Also, which way would I pull? Hear the joints/couplers direction matters but can't remember what I was told.
 
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Old 02-02-15, 03:09 PM
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Similar with buying bulk cable on a job like this, I'd recommend you buy a spool of 1000' (depending on all your actual distances) of 2" HDPE duct and lay that all in in one shot with your trencher at 2-3' down to every outbuilding that will be electrified. Better than loading, hauling and gluing 100 lengths of PVC. Work with your supplier to find a vendor with 1000' lengths they can ship right to your site on the same truck with your wire, panels and other stuff you'll need.
 
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Old 02-03-15, 10:49 AM
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Just googled HDPE duct, similar to the inner duct we install for fiber installs. Much easier.

In my paintbrush pic and in the post, I listed what I'd like to have at the end of the service. Really don't want to over install for a light, gate, or fan.
 
  #10  
Old 02-03-15, 12:59 PM
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Yep, same stuff -- comes in smooth bore or ribbed. When using it for line voltage you just need to convert to PVC before you come up out of the trench for protection against damage.

For the small loads (gate, etc) you could do a code minimum install of a single 20 amp 120V circuit using #12-2 UF-B cable, direct buried at 24". That will run about 50 cents per foot on materials. It would be a good idea on the runs over 100' to jump up to #10-2 UF-B to compensate for the voltage drop. That would be about 70 cents per foot.

Compare to a 2-2-4-6 direct burial aluminum cable at about $1.85 per foot which carries 90A at 240V. That's a lot more flexibility for future use of your buildings for an extra couple hundred bucks upfront while you already have trenches dug. You might even get a little better price if you can buy an entire roll. Certainly worth thinking about this option for all the buildings.
 
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Old 02-04-15, 12:18 AM
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Appreciate the input. Thanks.
 
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Old 02-04-15, 09:41 AM
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While I generally detest working with UF I would suggest running the HDPE duct to the gate and then pulling a 12-2 UF through it. This way if you ever wanted more power to the gate area it would be simple.
 
  #13  
Old 02-07-15, 08:29 PM
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How do I convert to pvc? Is there a coupler that goes from the duct to a pvc pipe?


ibpooks
Yep, same stuff -- comes in smooth bore or ribbed. When using it for line voltage you just need to convert to PVC before you come up out of the trench for protection against damage.


I'll post pics of the breaker in Cabin 1 that service the cabin and is a mid point between pole 2 and pole 3.
 
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Old 02-07-15, 09:12 PM
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Old 02-07-15, 10:52 PM
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Looks like they have a pic of the solution on the front page, thanks!
 
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Old 02-08-15, 05:59 AM
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How do I convert to pvc? Is there a coupler that goes from the duct to a pvc pipe?
I prefer the E-Loc couplings, they just drive onto the end of both the HDPE and PVC conduits. Check page 28, top left.

http://www.carlonsales.com/pdfs/HDPE/HDPE_Brochure.pdf
 
  #17  
Old 02-10-15, 11:41 AM
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Thanks CJoe.

Did some digging and want to redo the service. Pole 1 to 2 has conduit but it's about 9-10" under ground.

Also, forgot to get a pic of the cabin box. Probably not going to matter at this point since everything is too shallow and I'll have it done from scratch.
 
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