I am the owner's representative for the construction of a vehicle maintenance facility. This facility has monitoring of CO and NO2 levels. If a threshold level is met, an exhaust fan comes on and a fresh air wall louver is opened.
The electrical contract installed a bank of four starters along a wall for these exhaust fans. He brought in the line side conductors, from four separate breakers, into one enclosure and then fed the conductors through nipples in the sides on the enclosures to the other three starters. Same for load side to fans. These starters are three phase 208V. He jumpered a ground from enclosure to enclosure.
Apart from being a "cheesy" installation (in my opinion), this does not appear to violate 312.8. Since the conductors pass through the enclosures, does the starter still need to have a warning label that separate power sources are present?
Is there another section in the code that would prevent such a lazy installation? My concern is that if we have a problem, or flash event, in one starter, we could lose several other starters that are needed for life safety equipment.
It was an engineered project. A public project. While my experience has mostly been on private projects where engineering is a little more detailed, the design of public projects have a little more ambiguity to them to account for flexibility with different manufactured components (i.e. the exhaust fans). Sole sourcing is an issue with public projects and generally the lowest "responsible" bidder must be used.