This is one of two metal-clad service switchgear operating at 4160V that provide enhanced redundant support to
the local and long distance telephone loads at a telecommunications facility that was upgraded from a 480V system
while keeping that system in operation. These switchboards feature double busses, both commercial and standby,
which feed stacked automatic transfer circuit breakers that employ microprocessor-based overcurrent and directional
overcurrent protective devices. We were part of the design team whose basic problem was that the existing standby
480V generators supplied more fault current than the existing 1960’s vintage 480V switchboards could support. The
resulting design contributions saved the customer considerable amounts of time and money while providing a highly
elevated level of redundancy to their existing, installed, systems. We employed our “Look Ahead” PLC programming
algorithms to operate the thirty existing low voltage automatic transfer breaker pairs in concert with the four medium
voltage automatic transfer breaker pairs. This system employs PC-based networked monitoring located at the Master
Control Console and in the Power Support technical offices located throughout the building. This monitoring provides
event logging, load trending, and system monitoring including animated bus diagrams of the individual medium and low
voltage switchboards to enhance troubleshooting. This system has been recently updated with additional loads installed
in the existing switchboards along with their associated controls and monitoring.