Final answer:
The single-throw knife switch should not be installed in a way that gravity could cause it to close, as this could inadvertently complete a circuit, leading to unintended electrical flow and safety hazards.
Step-by-step explanation:
The question pertains to the installation requirements for a single-throw knife switch. In electrical engineering, the positioning and handling of switchgear are critical for safety and functionality. According to safety standards, a single-throw knife switch must not be installed in a way that gravity could potentially close the switch on its own, which may inadvertently complete a circuit and cause an accidental flow of electricity. Such an installation would pose a serious safety hazard. Instead, switches are designed to remain in the 'off' position when not in use, requiring manual actuation to close the circuit. Furthermore, while switches may sometimes be locked or require hand operation for safety or functional reasons, the key aspect to remember is that gravity must not act on the switch to move it to the 'on' position without intended human intervention.