Excessive current can be caused by:

Excessive current can be caused by:

• A. Short circuit
• B. Underload
• C. Overvoltage
• D. Loose connections

Answer: (A)

A short circuit creates a path of very low resistance, so the current in the circuit surges far above what the load designed for. Ohm’s law (I = V/R) shows that when resistance drops toward zero, the current becomes extremely large, limited only by the supply and the conductors. This sudden spike is what protection devices—fuses or breakers—are meant to interrupt. Underload reduces current because the circuit isn’t drawing as much as it was designed to, so it doesn’t cause a large current surge. Loose connections add resistance and can cause heating or arcing, but they don’t provide the low-resistance fault path that leads to excessive current. Overvoltage can push more current through a circuit with a given impedance, but without a fault creating a near-short, the current rise isn’t as dramatic as with a short circuit.

A short circuit creates a path of very low resistance, so the current in the circuit surges far above what the load designed for. Ohm’s law (I = V/R) shows that when resistance drops toward zero, the current becomes extremely large, limited only by the supply and the conductors. This sudden spike is what protection devices—fuses or breakers—are meant to interrupt.

Underload reduces current because the circuit isn’t drawing as much as it was designed to, so it doesn’t cause a large current surge. Loose connections add resistance and can cause heating or arcing, but they don’t provide the low-resistance fault path that leads to excessive current. Overvoltage can push more current through a circuit with a given impedance, but without a fault creating a near-short, the current rise isn’t as dramatic as with a short circuit.