converting from overhead power to underground

[jjcold]

I've been posting here a lot since they started building my house! You can imagine, huh?? So, here's my next crazy question:

I'm disappointed they aren't hooking the power up using an underground run. I guess it's more cost feasible here to go overhead. I hate the thought of having those wires to look at in my backyard, however, I think we'll just go with it for now.

Here's my question: Is it reasonable to expect that someday in the future I can ask the utility company (if I pay for it of course) to hook me up underground? The power pole is on the other side of a small gravel driveway, so they wouldn't have to drill under a paved road at all. In fact, I've been considering digging a trench and putting in the wire or conduit before putting in my back yard, so it would be all ready for it. Of course I'd consult first with the utility company to get specs, etc. Is this reasonable, or stupid??

[Rich]

I think it's very feasible. Typically you will need to be 18" minimum below grade and in a conduit. I would suggest putting in a 4" conduit with 2 pulls in it. You don't have to put the actual wire in the conduit just some heavy duty strings as long as there aren't any sharp bends.

[jjcold]

thank you for the speedy reply. why 2 pulls? What type of string would one use? I think to dig the trench (around 80 - 90 feet long I would rent a Ditch Witch? are they hard to use? I have some friends who I believe have used one.

Also, would you connect the conduit to the meter box now, or just cap it off as a stub below the box.

[Rich]

I always think you should add extra pulls. You never know what you might want to run through there in the future. More of a safety precaution.
There is some twisted string that is typically used for pulling through conduit - most of it is like a poly type and is blue and white in color.
Ditch witches aren't bad too use. Have your friend give you a quick run down on them - the rental store will help also.
I would cap the conduit off for now. Give yourself a good foot or more of room if possible between the cap and the box. Some of the couplings for 4" conduit can be pretty big.

[mreynolds]

Just a note for the underground stuff. I just did this summer, and make sure you have a pretty good idea about what type of soil you have. We happen to have large rocks underground and had I used a ditch witch it would of been useless(or I could of seriously damaged the machine). I rented a mini excavator with no experience on the machine and dug a 30 inch deep hole in a day for $150 (250 ft). When you factor in the cost of loading an unloading for an excavating contractor this was a good deal (unless he is there with you house already). Another thing to look at is the regs, around here they allow you to lay the cable deeper (30") and avoid the conduit as long as it is covered with clean fill. Thats too bad that they didn't go underground in the first place (It cost 250 for install with a temp pole and a breaker here). I have heard that changing over cost more because they already have you as a customer.
PS, don't forget you can lay your phone cable and cable TV lines in the trench also.

[Rich]

I do like mini-ex's. We have one on our jobsite right now digging a bunch of underground ductwork.

[mreynolds]

That was like getting to ride a go cart for eight hours straight. I got a fairly new Kubota, the controls were so smooth the machine just glided from one place to another. I have to say I was kind of jealous to realize that people get paid to do that for a living.

[Rich]

LOL... ever been in a tower crane 275' in the air? Now that's cool...and umm kind of scary at the same time.

[jjcold]

Stop it guys, you're getting me too damn excited! I can't wait to dig up my back yard (before it becomes a yard, really) and lay that stuff in there. I'll check on whether I can just lay the cable in the ditch. I presume in the long run that 'd be a whole lot cheaper. I'm going to call the power company tomorrow.

[cantwait]

jjcold, I'd like to share my electrical experience with you, if I may.
If you are in a "code inspected area" where the codes enforcement officer and/or electrical inspector will "visit" you to see what you've done you might consider the following; oh it won't take away the fun you'll have with your yard.

1) the passage under your drive since there will be vehicle weight therefore requiring the use of schedule 80, not 40 electrical conduit. This will be necessary to the "driveway area".

2) which leads me to this next item, I have been called to many homes where they had mucho rocks in their soil and "just laid the wire, bare" down in the trench only to have the freeze/thaw seasonal cycles force those rocks to rub and rub and rub until they, yes they will, tear a hole right trough the sheathing and caboom, out go the lights. And then you'll be redigging or paying someone to redig all that up to lay another new run.

100 feet of ELECTRICAL pvc is worth the savings of winter or future headaches. Don't use plumbing pvc, code illegal and not the same. You can use shedule 40 for the other areas and must schedule 80 for under the driveway. Some people have had sand hauled in to replace the "rocky soils" but that doesn't allways work. Rocks have ways of moving.

I agree with "admin" about two runs of cord, good strong nylon cord.

Have fun and enjoy!

[mreynolds]

jjcold just reminded me of a couple of things. When you contact the power company, they are very specific about what they will put cable into(At least mine was). They gave me about 4 pages of specs and what was allowed and what wasn't. In fact I had to use different soil on the bottom 4 inches of my ditch because it was so rocky, then backfill with clean stuff also. The morning we were going to install mine it happened to rain hard, I had to run to the rental compnay, get a water pump to clean the ditch out before the guys got there! :shock:

[jjcold]

thanks for the tips and help on this. Yea, I'm sure it will become a bigger job than expected, they always do! Last weekend I ran speaker cable in the living room walls (before insulation and sheetrock) for my home theater rear speakers. Even that very simple task became more than I had planned for when I realized my cathedral ceiling peak was taller than I had planned, and my 6' step ladder just wasn't quite going to do the job. well, I did (gasp) stand on the very top platform of the ladder and held on tight to the truss, and it worked out. the install came out fine.

I'll get all the specs and code on this underground conversion before doing it. thanks for the tip on the schedule 80 under the driveway. I think I will run conduit too.

[icthrooyou]

PS, don't forget you can lay your phone cable and cable TV lines in the trench also.

Getting ready to do this myself and wondering can the cable/phone be laid in the same CONDUIT as the electric, or are we talking about just the same TRENCH?

Thanks!

[Rich]

Same trench.. I'm pretty sure most codes dictate seperate conduits for power and any low/no voltage lines.