Swithchgear are the components of electrical systems used to de-energize and isolate circuits and equipment to protect-, allow work to be done and repairs to be performed.
DC (direct current) is very different from AC (alternating current). Do not use AC switchgear for DC applications unless the manufacturer advises that the component is rated for DC, and then indicates the de-rated volts and amps limits.
This includes switches, circuit breakers, isolators, fuses, disconnect-isolators etc.
Switchgear plays a very important role in the safety of an electrical system. Selection of components must match the application and design of the electrical (solar) system.