Motor drives, chargers, energy storage, and industrial controls often require galvanic isolation between high-voltage power domains and low-voltage control circuits. Isolation protects users and controllers, but it also determines whether signals remain reliable during fast switching events. Key selection factors include isolation rating, common-mode transient immunity, propagation delay, channel count, supply method, and package creepage distance. If the design includes converters, gate drivers, communication links, and sensors, the isolation strategy must be planned consistently. Isolation should be decided at the architecture stage rather than added after EMC or safety testing reveals weaknesses.