ATS Dual Power Switch

The first decision is the ATS class per IEC 60947-6-1. PC-class switches are purpose-built transfer mechanisms that carry and transfer current but do not interrupt short circuits, giving fast, reliable changeover; CB-class units are built from two interlocked breakers and add integral overload and short-circuit protection. Match the rated current and pole count to the system — 2P for single-phase, 3P for three-phase without switched neutral, and 4P where the neutral must be switched in TN-S/TT systems to avoid circulating or fault currents.

Transfer time must suit the load: electronically controlled switches change over in about 50 ms for sensitive electronics, while economical CB-class units transfer in roughly 1–2 s for general backup. A mechanical interlock is essential — it physically prevents both sources from connecting at once, protecting personnel and equipment from generator back-feed. Look for an intelligent controller with adjustable over/under-voltage detection on each source, and confirm compatibility with mains, generator, inverter, and PV sources as required.