True or False: Switches are the principal protective device in distribution substations.

The statement that switches are the principal protective device in distribution substations is false. In distribution substations, the primary protective devices are typically circuit breakers, which are designed to protect the electrical system from overloads and short circuits by interrupting the flow of electricity in case of faults.

Switches, on the other hand, are utilized for control and isolation purposes, allowing operators to direct the flow of electricity or isolate specific sections of the network for maintenance or during fault conditions. While switches play an essential role in operational management and safety by controlling the distribution of power and allowing for the safe maintenance of equipment, they do not serve as the main protective element. Thus, the claim that they are the principal protective device is incorrect.