In photovoltaic combiner boxes, isolation switches are indeed a common electrical safety device.

In photovoltaic (PV) combiner boxes, an isolation switch is indeed a common electrical safety device. Its main functions and importance are as follows:

1. Safety Isolation: During maintenance, servicing, or fault diagnosis of the PV system, the isolation switch can disconnect the electrical connection between the solar panels or the combiner box and the rest of the system (such as inverters, battery storage systems, etc.). This provides a safe working environment for maintenance personnel.

2. Preventing Electrical Accidents: When it is necessary to inspect or repair the interior of the combiner box, the isolation switch prevents electrical accidents by disconnecting the power supply, thus avoiding accidental contact with live parts.

3. System Control: In some cases, such as system upgrades or expansions, the isolation switch allows operators to turn off the power to specific parts of the system without having to shut down the entire system.

4. Protecting Equipment: In PV systems, there are situations where it is necessary to physically disconnect a circuit to protect electrical equipment. Although the isolation switch itself does not provide overload or short-circuit protection, it is a key component for achieving this physical disconnection.

5. Compliance with Standards and Safety Regulations: Many countries and regions require the installation of isolation switches in PV systems as per electrical safety standards to ensure operational safety and system reliability.

Therefore, including appropriate isolation switches in the design and installation of PV systems is a crucial factor in ensuring the safety and efficient operation of the entire system. This also helps protect the safety of maintenance personnel and prevent electrical failures and accidents.