Final answer:
The correct option is B. A positive means of disconnect is required for electrical connections exceeding 50 volts to ensure safety during maintenance or emergencies, making (B) 50 volts the correct answer.
Step-by-step explanation:
Positive Means of Disconnect for Electrical Connections. According to safety standards, a positive means of disconnect is required for electrical connections to ensure the safety of maintenance personnel and equipment. This requirement is particularly necessary for systems that operate above certain voltage thresholds. The question pertains to this voltage threshold, which dictates when a positive means of disconnect is necessary.
For voltage levels exceeding 50 volts, a positive means of disconnect is typically mandated. This ensures that systems can be safely de-energized, preventing electrical shock or other hazards during maintenance or emergency situations. Therefore, the correct answer is (B) 50 volts. It should be noted that different countries and regions may have varying standards and regulations, but broadly speaking, 50 volts is a commonly accepted threshold for requiring a positive means of disconnect.