In this picture the two banks of 4" towards the back are utility secondaries. I am taking the picture at about the corner of where the transformer will be. Obvious is the difference in length of the two duct banks. One of the requirements for this utility on a service of this size is a six foot separation between ductbanks. The reason is for heat dissipation. I initially had the conduits running together because it is such a short run it was impractical to obtain the required 6ft separation but was made to do this by the big boss at the engineering Dept. Maybe they don't understand how parallel conductors operate. (Granted they will probably only pull conductors in three of them anyway) [Linked Image]
Do other utilities have this requirement around the country? They must not have problems with it or they wouldn't keep up this practice.

[Linked Image]