Disconnectors must disconnect which terminals of the battery?

Disconnectors are designed to safely isolate the electrical system from the battery to prevent accidental short circuits and reduce the risk of electrical fires when maintenance is being performed or when the vessel is unattended. For comprehensive isolation, disconnectors should interrupt the electrical circuit by cutting off both the positive and negative terminals of the battery.

By disconnecting both terminals, the system is completely de-energized, ensuring that there is no potential pathway for current to flow, which mitigates the risk of shock or equipment damage. If only one terminal is disconnected, the other terminal may still provide a return path for current, which can lead to dangerous situations. Thus, the correct practice and standard recommendation is to use disconnectors that isolate both the positive and negative terminals.