A building that I do quite a bit of work on has asked me to give them a price to upgrade the current service (400 amps 3 phase) to 1000 amps 3 phase 120/208.
Presently there are 2 underground 4" rigid conduits run from the pole to the building, 1 supplies the 400 amps and the other supplies the telephone service. The phone company has agreed to provide an overhead service to the building which will allow us to use both 4" conduits to serve the new service. I propose installing paralell 600 kcmil copper to feed a new 1000 amp CB/CT cabinet. To excavate new conduits to the building would be a huge job and the power co has said they will not supply an overhead 1000 A service.
Does this sound reasonable? I'm curious as to how well 4-600 kcmil copper will pull thru the 4" (the total run is approx 125'). I think I will run all of this by an engineer but I would appreciate any opinions.
Thanks
