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- Automatic Transfer Switches - Confirm and apply settings provided by others. Collect and record identifying nameplate data, construction, design, ratings, and components. Compare to project plans and specifications. Perform mechanical services necessary to assure device operates as intended. Perform tests to confirm correct operation of all functions.
- NEC Article 700 - Emergency Systems To apply the requirements of the National Electrical Code's as it relates to Standby Power Systems we need to understand that there are three different types of systems recognized by the NEC. They include emergency, legally required, and optional standby systems; the requirements for emergency standby systems are contained in Article 700, legally required requirements are in 701, and Article 702 covers optional standby systems.
- Transfer Switch Testing and Maintenance Guide This guide provides information on the general inspection, operation and maintenance procedures of transfer switches in emergency power systems.
- Testing Automatic Transfer Switches [PDF] One of the most misunderstood devices in an emergency power system is the Automatic Transfer Switch (ATS). ATS's automatically switch a load from a preferred source (normal) to a backup source (emergency) upon a normal source failure.
- Monthly Transfer Switch Tests The NFPA, Joint Commission on Accreditation of Healthcare Organizations (JCAHO), and all major ATS manufacturers publish literature calling for the monthly test of ATSs, yet many facility owners ignore these guidelines and refuse to perform the tests. There are good reasons for both the monthly-test requirement and for the reluctance of many operators to comply.
- Switching the Neutral Conductor [PDF] Automatic transfer and bypass switches are made in two, three and four pole versions. The two and three pole variety are generally understood as to usage and ampere/voltage rating of the load carrying contacts. The use of the fourth pole to switch the neutral is less commonly understood.