Best practice: use switch-guards for critical circuits

For cases where inadvertent use of a switch could impact the safety of the vessel or its occupants, ensure that the switch is guarded.

For example, a switch controlling power to a primary DC bus on the vessel should be guarded to prevent accidental powering down of multiple systems. Similarly, a soft-switch on a touchscreen display that operates a moving item of equipment (such as a powered hatch cover), should be designed with a software guard.

For physical switches, install a purpose-built guard (such as an integral flip-cover).

For soft-switches on a touchscreen display, consider implementing:

a “long press” feature. For example, enforce a three-second press before a soft-switch signals that AC shore-power is to be connected or disconnected from the vessel’s electrical system.
a confirmation message that the user must acknowledge to complete the action (for example, “Power-off the primary DC bus? <Yes>/<No>).
an access code (PIN code) that the user must enter before gaining access to a soft switch.