trying to figure cable and pipe size

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mikeyg15

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retired electrician
My son just landed a nice job but we need a little help with calculations . 800 amp meter pack on side of bldg #1with 2 spare 200 amp 3/phase breakers. Owner wants to use spares to supply 3/phase power to building next to the one with meter pack. Plan is to come out of meter pack and run 2 pipes up on the outside of bldg then run through that bldg high up close to roof ., heres where it gets interesting theres is a driveway between the 2 bldgs that gets some use by one of the tenants , Owner doesnt want to bridge between bldgs (approx 20 feet) , wants to come down and go under driveway and come up again to enter bldg where 2 new services will be located. Length of runs will be 300' and 340' , copper is way to expensive so aluminum would be used , its commercial so 4/0 aluminum I think would be enough . According to the tables 2 1/2 " pipe would be large enough for 4 4/0 conductors with a #4 ground . The problem i see is if we pipe it continuous we would be pulling through 4 90's or we could install a jb on each bldg and do a lot of re rigging the pulling gear. My thought is to oversize the pipe to 3" if we dont use jb's between the bldgs , which with a lot of soap should make the pull go relatively easier. I havent been active lately and i know a lot of codes and regs have changed , so im double checking my idea with you guys what do ya think ? thanks
 
Instead of going up over and down, can you just go down right away?

Pull box like you mentioned maybe a good idea even if you went with 3", or a conduit body.
 
owner doesnt want to dig up parking lot and disrupt business have to go through one building up high the come down go under driveway and come up other side of building getting new services
 
I would use 3" and try the full pull, in the direction that allows gravity to help feed; sounds like toward the meter here.

You can dump some lube in strategic places when you assemble the conduit, so the wire gets re-lubed along the way.
 
thats my thought also larry , i can put a pull box in the second bldg just inside where the conduits will enter the bldg , from there it should be pretty easy going . Theres going to be a pull box on the first bldg going to both the meter pack and the runs through the warehouse , im thinking i should be ok with the 4/0 aluminum for the 200 amp 3/phase 4 wire system , or should i be concerned about derating and going larger ?
 
both spaces currently have single phase he doesnt even care about 3 phase he does light assembly work the other space is vacant and most prospective renters are looking at 3 phase , i dont forsee any big machinery needing power
 
mikeyg15 said:
both spaces currently have single phase he doesnt even care about 3 phase he does light assembly work the other space is vacant and most prospective renters are looking at 3 phase , i dont forsee any big machinery needing power
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You said 4-4/0 and a ground. That is 3 phase. 3-4/0 and a ground fits in a 2"
 
Yes 4 4/0 and a ground 3 phase ,5 wire, neutral and ground sorry for the confusion , i know the tables say 4 4/0 will fit in a 2 1/2 inch , but if i try pulling around 4 90's i think i should oversize the pipe to 3 inch . Help is hard to get nowadays and experienced help is even harder so we are trying to keep it as easy as possible due to inexperienced help
 
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