What is a potential hazard when an A-base meter's current coil is connected in parallel under energized conditions?

• A. Ground fault
• B. Voltage spike
• C. Overheating
• D. Explosive dead short

Answer: (D)

When the current coil of a meter is placed in parallel with an energized circuit, you create a direct, low-impedance path across the supply instead of the intended path in series with the load. The current coil is designed to carry a limited current in series; in parallel it effectively short-circuits the source, and the fault current is largely determined by the supply and the coil’s own resistance. This sudden, massive current surge can cause rapid heating, insulation damage, and arcing at connections. The energy released in such a dead-short situation on an energized system can be violent enough to rupture the meter housing or cause other catastrophic failure, hence the term explosive dead short.