Which of the following types of isolating devices is permitted for PV system equipment?

The correct choice highlights the use of a mating connector that meets specific requirements for isolating devices in photovoltaic (PV) systems. Mating connectors are specifically designed to disconnect and isolate electrical equipment safely, ensuring that maintenance can be performed without risking electrical shock or damage to the system. These connectors must comply with relevant standards that guarantee their reliability and safety for the application in a PV system, making them an appropriate choice for isolating devices.

The other options are not as suitable for PV systems due to various reasons. An isolating switch that is easily operated is indeed useful, but its design and construction must meet certain standards to ensure it can handle the electrical load and provide safe isolation, which may not always be the case. Toggle switches, while common in many applications, are not typically designed for the harsher electrical conditions and safety requirements found in PV systems. Similarly, a manual push button does not provide a reliable means of isolation for high-voltage systems, as they are generally not intended for that purpose in the context of electrical safety and performance in PV installations.