Re: Service Entrance conductors
In Washington State, the disconnecting means has to be within 15 feet of where the conductors enter the building. The existence of that WAC rule confirms (to my mind, at least) the absence of a similar distance requirement within the NEC itself. Of course, if you do keep the conductors below 2 inches of concrete (as Mike pointed out), you can run them to the other side of the building. I have used that design. The conductors don't "enter" the building until they come up from beneath the concrete barrier.
Charles E. Beck, P.E., Seattle
Comments based on 2014 NEC unless otherwise noted.