Factors to consider when upgrading transfer switching equipment to present codes and standards

Some of the steps that should be considered when expanding or replacing equipment in emergency and standby power systems are discussed. The need for code conformance, reliable operation, and safety to personnel is discussed. For a better understanding, derived systems, ground-fault sensing, the impact of NEC (National Electrical Code) changes on yesterday´s and today´s installations, and the limited degree of isolation provided by three-pole transfer switches are reviewed