Overhead to underground service residential

[strutaeng]

Hi all. I'm building a house addition and the new framing is where my addition is. To start new framing I need to move power line. Addition is bedrooms and large family room.

My original plan was to put a temporary pole and power house from there. After framing and finishes were up install a new main, then feed to my existing panel (convert existing to a subpanel.) That's a lot of trigger work. I have gas service and appliances, but do also have a subpanel to detached garage, that I run a welder and 7.5 HP air compressor a few times, not at the same time.

As I was walking with my electrician, it struck me that if convert the overhead to underground, I don't have to do all of the extra work. The area on this side is a little tight, and I had just dug and buried a 6" drain pipe at about 18" deep. I pulled the electric service guideline from my provider and they have pipe at 24" from to top of conduit to grade. Also, some areas when I dug the drain pipe have solid limestone. I had to use chipping hammer to get to the depth and pipe slope. That was a lot of work!

I called my electric provider and they are sending a technician to take a look at it. My electrician said he has only done this in new houses and he installs the conduit and provider runs wire, but he said they only run something like #2 Al triplex or something? He said they'll ask you what kind of appliances you run. Seems light to me, but I guess that's how it's done.

Has anybody done this?

 

[wyliesdiesels]

Your post is a bit scattered.

Are you asking if someone has converted from overhead to underground?

sure! happens all the time.

However, it IS location and PoCo specific, so not really much we can give you here on a forum.

 

[strutaeng]

Yes, that's basically what I was asking. I didn't think this was something one could do...

 

[wyliesdiesels]

Yes, that's basically what I was asking. I didn't think this was something one could do...

Well this is a PoCo and locale specific question/situation so unless someone on here lives in the same area as you and has the same PoCo, there isnt much we can help with.

Best to speak with your PoCo engineer, technician or representative...

 

[Farmallboy15]

I did this last spring. I dug the trench and ran the conduit to the pole. The power company paid for and installed the wire in my case. They were happy to go underground to eliminate the risk of downed trees on the line.

Once the conduit was in place the poco cut power. Electrician removed Old meter base. Installed a new one and the poco pulled and hooked up the wire. Easy peezy, done in a couple hours (For two services). Except the mud keeping the poco truck away from the pole they were replacing...

 

[dcg9381]

I agree that this is PoCo specific. They can and will tell you what to do, regardless of what the NEC or anyone else says. Mine had several diagrams of what was "acceptable" installation. Just tell them what you want to do. If possible, find someone else in the same area that has a similar deal and take a photo.

 

[strutaeng]

Well, I finally have completed the work! I paid a guy that dug the trench. About 27" deep for 24" cover from grade.
I had about 6,000lbs of limestone to haul to the landfill from the excavation!

It is not inexpensive! I ran the conduit and the electric's contractors ran the wire. The electic company was out again today to do the riser at the pole and take down the overhead line and my electrician removed the mast and powerhead at my house.

I wasn't here, my wife said we were without power for about 30 minutes.

 

[75gmck25]

I'm in Virginia, just outside DC, and the process is a little different.

- Pull the permit for the underground conversion and pick up a new meter base from the POCO.
- Electrician installs the new meter base inline between the panel and the old meter base.
- Meter base installation and connection to panel is inspected and approved.
- POCO's tunnel contractor runs conduit for the new underground line. Mine crosses the street and my front yard, so they dig a hole on either end and then tunnel the conduit under the street and yard. Apparently they will also tunnel in a low voltage conduit for cable and telephone if I pay extra. The charge for the power conduit and cable is about $2,500, and it will be going about 60 feet underground.
- POCO comes out and moves the electrical connection to the new meter base on my end and to the pole on the other end to activate the underground power line.
- The one big catch in this is that it usually takes 4-6 weeks to schedule the tunneling contractor, which does not match well with my framing schedule.

Bruce