I am wanting to add a 40'x60' workshop on my property (36.5 acres in East Texas). I already have two meters at opposite ends of the property and will add a third meter for the workshop and a future home site for retirement.

I am going to have the pole placed near the home site about 100' inside the property line. The workshop will be about 400' from this point. What I plan on doing is running service from the meter to the home for 100amp and to the workshop for 200amp. I am trenching for the waterlines now and want to install at minimum, the underground PVC for the electrical with a pull line.

Questions:
1. What size/type of wire is required for underground installation in sandy soil at a distance of 400'?
2. What size PVC should I use?
3. Can the installation occupy the same trench as the 1" PVC for water?
4. There is a 90 degree bend at about the halfway point. Should I use an access box for pulling, etc?
5. I am crossing a creek with a 24' bridge. Are there special considerations for this?

I am a bit unclear of the service size, 100 amp for home and 200 amp for shop. Does this mean 200 amp main and 100 amp off that? Or a total of 300 amp?

In any case, 400 foot is a long run for 120/240 volts. The wire size will need to be very large. Before I size it I really need to know the maximum load in amps.

For example, if I assume an actual load of 200 amps, if #500 MCM aluminum was used, the voltage drop would be 4.8%. Not too bad, but recommended max is 5% for both feeder and branch circuit, the last outlet on a circuit.

So that would mean realistically, either #600MCM or #750 MCM aluminum would be needed.

Voltage drop calculations are entirely dependent on knowing the real load in amps, or projected as best as possible.

I really need to recommend that you try to extend the utility line using high voltage, for this long run.

You may need to provide your own underground conduit line, and HV cable, abnd a ground mounted transformer, at the first building. The wire size can then be much smaller, probably #2 or a bit larger copper. This would be much more practical. The chore will be how to get this done. Does the local utility offer this as a service to customers? For a cost of course. Or is there a local electrical contractor that does high voltage work?

Water lines usually can occupy the same trench as electric conduits, done all the time. Typically a two foot wide trench is dug, and both utilities are keep apart by keeping each on there own side.

Definitely , no sweeps in this long run, use flush with grade handholes or manholes as pull points. Try to have no splices.

To cross the creek, are you planning to go under the creek, or support exposed conduit on the bridge?

Under the creek is very possible, but very expensive if done with directional boring method. For example, I had two 5" conduits installed under a paved parking lot, 260 feet, for $35,000.00. Your should be much less, but just to give a feel of what this method costs, in New England.

If you cross the bridge with exposed conduit, I believe steel rigid conduit for that exposed portion is the best. I had to do the same thing on a 60 foot long footbridge on the same job with the directional boring. Exposed horizontal PVC in the sunlight just does not work, sags and expands too much.

I know I have not answered all of your questions. I hope I got you thinking and going in the right direction.

See about extending that HV line as the 120 volt does not like 400 foot runs so much.

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Originally Posted by chuckhole

I am wanting to add a 40'x60' workshop on my property (36.5 acres in East Texas). I already have two meters at opposite ends of the property and will add a third meter for the workshop and a future home site for retirement.

I am going to have the pole placed near the home site about 100' inside the property line. The workshop will be about 400' from this point. What I plan on doing is running service from the meter to the home for 100amp and to the workshop for 200amp. I am trenching for the waterlines now and want to install at minimum, the underground PVC for the electrical with a pull line.

Questions:
1. What size/type of wire is required for underground installation in sandy soil at a distance of 400'?
2. What size PVC should I use?
3. Can the installation occupy the same trench as the 1" PVC for water?
4. There is a 90 degree bend at about the halfway point. Should I use an access box for pulling, etc?
5. I am crossing a creek with a 24' bridge. Are there special considerations for this?

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Wow. What an eye opener. I was hoping to supply 200A in the shop but I see now that is going to be cost prohibitive. A preliminary check on prices shows that is going to be at least $16K just for the wire. That is almost the cost of the building.

If the electric company goes above ground (and I have been told two poles plus a meter pole is all they would run) then they would be cutting a wide pathway and lots of trees which is why I want to go underground.

I guess I will have to cut back to 100A service for the shop. Other than lighting, the heaviest single draw will be a 240V, 20A MIG welder. I would assume then that 4/0 would be sufficient and that a 1-1/2" pipe would be minimum and 2" would be preferrable? The information I found is that 4/0 has a diameter of just under 1/2" and I would need to run three wires total.

I would have to look it up, but off the top of my head 1/2" sounds small for 4/0, and 1 1/2"
Sounds small for 4/0. Don't want to give sizes until I or someone looks it up, or TK probably knows off the top of his head.

Multiple wires must not fill a conduit more than 40% of the space in a conduit.

Smallest conduit allowed will be 2" PVC Sch 40.

For a long run, larger conduit is used to help with the pull.

Believe me, use larger conduit, you will thank me, along with wire pulling lubricant.