ayerforce
Member
- Location
- Hubertus, Wisconsin
- Occupation
- Electrical contractor
I need a second opinion on this one. Industrial building with 480Y/277 volt service.
60 ampere breaker in panelboard serves a 45kva 480 delta x 208Y/120 volt transformer. A separately derived system with respect to the building service. X0 bonded in transformer. GEC to building steel. 125 ampere feeder to fusible disconnect, then load center for UPS, IT equipment and other receptacle loads.
I would like to install a 48kw generator with 208Y/120 volt output to feed this load center through a 200 ampere transfer switch, non-service rated. 125 ampere fuses in fusible switch between generator and transfer switch. The generator is an SDS with respect to the building service. Neutral bonded at generator output. GEC to building steel. MCB in generator. Both my transformer SDS neutral and my generator SDS neutral will be terminated on a common bus in the transfer switch.
In the back of my mind, it seems as though I should be using a 4-pole transfer switch here, but I can't put my finger on the reason why (either code rule or functionality). Alternatively, I could use a generator with a 480 volt output to feed the primary of the transformer, but I'm concerned about the generator seeing the inrush from the transformer and having to up-size it significantly to avoid problems.
Any thoughts would be appreciated!
60 ampere breaker in panelboard serves a 45kva 480 delta x 208Y/120 volt transformer. A separately derived system with respect to the building service. X0 bonded in transformer. GEC to building steel. 125 ampere feeder to fusible disconnect, then load center for UPS, IT equipment and other receptacle loads.
I would like to install a 48kw generator with 208Y/120 volt output to feed this load center through a 200 ampere transfer switch, non-service rated. 125 ampere fuses in fusible switch between generator and transfer switch. The generator is an SDS with respect to the building service. Neutral bonded at generator output. GEC to building steel. MCB in generator. Both my transformer SDS neutral and my generator SDS neutral will be terminated on a common bus in the transfer switch.
In the back of my mind, it seems as though I should be using a 4-pole transfer switch here, but I can't put my finger on the reason why (either code rule or functionality). Alternatively, I could use a generator with a 480 volt output to feed the primary of the transformer, but I'm concerned about the generator seeing the inrush from the transformer and having to up-size it significantly to avoid problems.
Any thoughts would be appreciated!
