I'd like to get opinions on a slightly odd proposal I've gotten to have 4 subpanels added to a building.
I need 4 separate sub panels to be installed on the exterior of a building spaced evenly over a distance of approximately 600'. Each of the four panels needs to provide a dozen 277V single phase branch circuits. Total load for each panel is under 40A (single phase) but nobody makes a 40A 480/277V 3R panel so the ones I'm getting are bigger.
Here's how our electrical contractor is proposing to do this:
We've got ample capacity at the MDP and several spare breakers. He wants to install a single 480/277V 4W 3phase feeder from the MDP and run this feeder the full 600' along the outside of the building. He wants to tap off of this feeder at 4 locations, one for each sub panel. Each sub panel will have it's own main breaker.
I can't find anything wrong with this scenario except that I'm so used to seeing a separate breaker in the MDP for each sub panel and not used to seeing a single breaker that feeds 4 separate panels.
I know that printed descriptions are hard to follow so here' s a quick sketch.
I'd like to hear your thoughts on this.