- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
I have to provide power to a set of 23 trailers that will serve as temporary classrooms while a school building is being renovated. The school district owns the existing overhead medium voltage distribution system, so the NEC applies. The plan is to run new overhead lines through the ?trailer park,? with step-down transformers every other pole or so. The transformers will be single phase 12.47KV primary, single phase 120/240V secondary. I want each transformer to serve 3 to 5 trailers, each of which will have its own MCB panel. My reading of the NEC tells me that I need to provide a 2-pole fused cutout on the primary of each transformer, and that the total ratings of the MCBs on the trailers? panels cannot exceed 125% of the transformer?s secondary current rating. But the transformer vendor rep is telling me they don?t provide accommodations for multiple connections on their secondary terminals. Are there approved connection kits or make-shift-split-bolt thingies that will allow me to do this? Can I simply put a note on the drawing to instruct the contractor to provide the necessary number of taps, and let the contractor figure out which pieces and parts to use? Like most engineers who have never done hands-on installation work, I cannot quite envision how this will look when it is built.