Final answer:
Exposed live parts of motors and controllers must be guarded against accidental contact if they operate at 50 volts or more, with enclosures or location acting as safeguards. High voltages greatly increase the risk of electrical shock, so safety features, including circuit breakers and insulation, are critical.
Step-by-step explanation:
The question pertains to safety standards for the equipment operating with electricity, more specifically in an engineering or industrial setting. The student is asking about the guarding of exposed live parts of motors and controllers. According to safety regulations, exposed live parts of motors and controllers operating at 50 volts or more between terminals should be guarded against accidental contact. This guarding can be achieved through proper enclosure or strategic location to prevent unintentional interactions. The provided information suggests an understanding that at high voltages, safety is paramount due to the risk of shock and the potential for serious injury or death. For instance, voltages much less than 335 MV, which is way too high and well beyond the breakdown voltage of air, are sufficient to pose serious dangers, while voltages as low as 120 volts can be hazardous when the resistance of the body is low, such as when wet. Furthermore, devices like circuit breakers and properly insulated wires are essential for preventing thermal and shock hazards. Safety features like ground wires and cases around appliances also contribute to preventing contact with live wires, reducing risks significantly.