What does the level of fault current at a work location depend on when working on a hot secondary circuit?

• A. The distance from the work location to the transformer
• B. The conductor size
• C. The conductor type
• D. Only A and B

Answer: (D)

The fault current available at a work location on a hot secondary circuit is determined by the impedance of the path from the transformer to that point. The longer the path (greater distance), the more resistance in the way, so the fault current is reduced. The cross-sectional size of the conductors also matters: a larger conductor has lower resistance, which lowers the path impedance and allows more fault current to flow. The conductor type isn’t treated as a separate factor in this quick assessment, since its effect on impedance is already reflected through the chosen conductor size and material in the system’s resistance values. So, the fault current depends on distance and conductor size.