Electricians question on underground cable

[36tbird]

Hi all,

Here is the scenario. There is an existing older house on the property but I think it has a small capacity hookup, maybe just 75amp. I want to keep that little house as a guest house and install a new meter to replace the old one and run service to the new house underground, about 160'. If I read the NEC correctly, I need to dig an 18" trench for PVC. Later on, above the route of the trench, I plan on a typical garage with a concrete slab. Again, reading NEC snippets on line I think the the PVC with the electric cable under the slab is OK. Should I run a separate PVC and cable from the new expanded meter to a stub for the future garage or just T off of the one going to the new house?

Don't worry, I will have a licensed electrician do the work, but I am just trying to get smart for planning the work.

If my assumptions about the depth of the trench and laying a slab over it later are wrong, please correct me. Thanks in advance.

 

[speed bump]

If your electric company is anything like ours it will be way cheaper for you to move the service to your new house and feed 2-2-2-4 back to your guest house.

Also running underneath the slab is going to require taking out the line when you go to do the earthwork for the garage.

 

[pmiranda]

If you're in the south, 18" might be deep enough but you'd still have to go deeper or around the slab footers for that garage. Probably easiest to go around the future slab if you can.
In the north I think they want utilities deeper than that.
Some of this depends on where you are... I suggest you put your rough location in your profile.

 

[36tbird]

Thanks. I actually meant to say South Central Texas and forgot.
For weeks now of not getting any electricians I called to call back, today I listed on Home Advisor and had 3 calls in less that 1/2 hour. I already talked to a couple of them and the project definitely seems doable. Regarding going under the proposed garage slab, after the trench is cut, there will need to be a lot of earthwork to bring in some fill so the line will actually wind up being a lot deeper.
Thanks again for the tips.

 

[Falcon67]

Yep, where he is most everything is slab on grade. IIRC, you can go 12" if you put concrete on top of the run unless it's across a driveway. Maybe for a short run, but for 160' that calls for a trencher LOL.

 

[Cyberbear]

Have you considered having a new separate service installed at both locations? Where I live the power company does this all the time, and it's kinda nice knowing what the electric bill is for each location, especially if the existing place ever becomes rental property.

 

[36tbird]

Trying to get our CPS to put in another service is like pulling elephant teeth. So, I will just have to expand the service and trench it to the new house. Got some great help here, thank you.