Which type of current must protective grounding equipment withstand?

Protective grounding equipment is specifically designed to withstand fault current. Fault current is an unintended electrical current that flows through a ground fault, which can occur during electrical failures or insulation breakdowns. This current can reach very high levels, often significantly exceeding normal operating current and can cause severe equipment damage if not properly managed.

The grounding equipment serves to divert this fault current safely into the ground, preventing it from causing harm to personnel or equipment. It must be robust enough to handle the maximum fault current that could occur in the system, ensuring that it provides an effective path for the energy to dissipate safely.

In contrast, surge current refers to temporary, excessive voltage spikes that occur during events such as lightning strikes or power surges. Normal operating current is the amount of current that flows under regular operational conditions, which is much less than fault current. Short-circuit current, while related, typically describes a specific scenario where there's a fault in the circuit resulting in a very high current flow, but protective grounding is primarily concerned with the overall capacity to handle fault current effectively for safety.