Question about UG electrical service conduit to shop building

[grsthegreat]

955Lincoln: when the house was built in 1980 the main panel was installed and directly wired to the meter. The neutral and ground were at that time bonded together. My point exactly, the newly installed main panel at the pole and the original house panel both have the neutral and ground bonded together which I think is a no, no!

Guys, your missing my point. Unless there is an actual ground wire running between the NEW main meter panel and the old house panel, you do not have to separate the ground wires and the neutral wires at the old house panel. You only have to make sure that there is a ground rod at the house panel. This type of wiring was perfactly legal in the 1980's, and you dont hve top change it. Just make sure that there is a ground rod. Now, if there IS a ground wire run along with the 3 main wires between the panels, then yes separate the grounds and neutrals.

 

[TC65023]

GRS: yes, the panel at my house has a insulated copper ground wire connected to a 8 foot long copper grounding rod, that I drove myself in 1980.

 

[955Lincoln]

Update: yesterday I got both the 2 inch and 3/4 inch conduit in the 230 foot trench and backfilled. The work went about as expected, most of it is 2 foot deep or more. Avoided hitting the electric and telephone service to the house. Cut through a old brittle drain PVC pipe from my well pit which needed rerouting anyway. I will do that over the weekend. Ran into a ton of rocks, will be picking them up later today and hauling to a ditch. Hopefully will get the entire area dressed down and seeded early next week before it rains again.

Expect to install the 1 inch PEX water service line, shut-off valve and frostless hydrant next week with the 4 inch SDR35 sewer line work to follow. Will dress up the final grade at the outside building wall and begin concentrating on the inside work.

You sure have be beat all to heck. I have been trenching on the weekends since May and only have 700' done....lots of rain delays though and the creeks are very time consuming. Pretty much backfilling by hand with a garden hoe to keep the big rocks out. I have found that I'm doing double the work by bedding 2 conduits at different vertical levels so I want to try switching from a 12" to 24" bucket and just doing it once with horizontal seperation at the bottom of the trench.

I'm pulling out so many rocks that I'm running out of soil to fill the trench back up.

 

[TC65023]

955Lincoln: I only had 230 lineal feet of trench total, all of it through my yard. I did the side by side conduit installation, it saves a lot of time. I had to contend with a lot of rocks, just not as many as you have. I backfilled the trench with the mini-backhoe blade which is great for that job.

Also, I didn't have to go through any creeks, thank god. I did haul two pickup loads of rocks and boulders to the ditch today, my back is killing me tonight too.

For good measure, I lit a big brushpile about noon and I can still see the glow a quarter mile away tonight.

Its supposed to rain early this week, expecting about 2-3 inches, just might put some water in my new pond that I finished seeding last week.

 

[TC65023]

Update: yesterday afternoon, a friend and I finished installing the 200 foot water line extension to the building. I used blue 3/4 inch PE water pipe with SharkBite connectors, which really went well. Also, installed a new yard hydrant and corp stop at the building entry point

I will pickup and haul rocks most of today and will likely seed the electrical, telco, water and sewer trench areas over the weekend. All the site utilities are now roughed-in to the building except for the installation of the electrical service conductors which I will start working on before the weather goes to crap. I am having some issues finding 2/0 aluminum XHHW locally. I probably just need to check with a local wholesale electrical supply house and forget trying to buy the stuff from Lowe's or Menard's.

 

[955Lincoln]

Thanks for the update. I have been wondering though, why 2" for the electrical? It seems 3" would have made things a lot easier.

 

[TC65023]

955Lincoln: here is the issue as I understand it concerning the feeder and conduit size:

My one-way length of run from the meter pole to my building panel location is approximately 250LF. I needed the wire sized for the 100 Amp
panel to address the voltage drop issue. So that size in aluminum is 2/0. The largest conductor my panel lugs will take is 2/0. Since since 2-2/0 XHHW plus 1-1/0 neutral and a copper ground wire easily fit into a 2 inch conduit, that seemed a reasonable choice.

I could have installed a larger 3 inch conduit at twice the material cost but I wouldn't have much unless I also changed to 4/0 conductors...I just didn't see spending the additional money for something I probably didn't need. Also I already had the panel so I didn't want to return it for a larger more expensive unit.

 

[grsthegreat]

955Lincoln: here is the issue as I understand it concerning the feeder and conduit size:

My one-way length of run from the meter pole to my building panel location is approximately 250LF. I needed the wire sized for the 100 Amp
panel to address the voltage drop issue. So that size in aluminum is 2/0. The largest conductor my panel lugs will take is 2/0. Since since 2-2/0 XHHW plus 1-1/0 neutral and a copper ground wire easily fit into a 2 inch conduit, that seemed a reasonable choice.

I could have installed a larger 3 inch conduit at twice the material cost but I wouldn't have much unless I also changed to 4/0 conductors...I just didn't see spending the additional money for something I probably didn't need. Also I already had the panel so I didn't want to return it for a larger more expensive unit.

you dont need a copper ground wire. Use a #6 alum wire for ground within the conduit. Use a #6 bare copper for the run between the new panel and the ground rod yo drive at new building. As for the 3"... wait till you try pulling all 250 feet of that wire thru 2" conduit...youll wish you went 2-1/2 or 3" hehe. it can be done, but it will be a chore unless you have a wire puller rig.

 

[TC65023]

GRS: thanks for the input, I should have done some more research on grounding wire types and sizes.

I'm not too worried about pulling the conductors 200 plus feet, if there is an issue I can pull both wide sweep 90 bends fittings and the run is basically a straight pull. Also, my electrical guy works for a large commercial electrical contractor and has access to a pulling machine to install the conductors.

 

[grsthegreat]

cool. those pullers and socks make all the difference in the world. I never bought one myself, but i can usually scrounge one up from friends if needed. I pulled my own shop using a pully hooked to my front end loader. worked slick.