If I was designing this job I would use a free standing switchboard which contained a pull section, CT compartment and distribution section. The distribution section could contain the 4 breakers for the heaters and 1 or 2 breakers supplying the panels for other loads. If less then 6 breakers are installed a main disconnect would not be needed. This would also make the grounding electrode/bonding very easy since you would just need to connect 1 panel.
From reading these forums over the past couple of years I see where things like this get done very differently around the country and Canada. Apparently it is cost effective to build a service like this in some areas but I couldn’t even purchase the materials for the cost of having a switchboard built. The only way I would every build something like is if I didn’t have time to wait for the gear to be build. I can usually get something like this in 3-4 weeks (sooner for more $$$) but seldom is the equipment needed for a new building that quickly.
Curt
