Solar photovoltaic (PV) systems use rotary DC isolators with multiple current and voltage ratings more commonly than DC rated circuit breakers. However, the flexibility of these DC isolators introduces instances of incorrect wiring when the manufacturer’s specifications are misunderstood, resulting in DC isolators being underrated for the PV system installed. This document is written to help with interpreting the product manufacturer’s data in the correct selection of DC isolators to meet requirements set out by the Australian Standards.