Question 32 CEL02 - Chief Engineer - Limited (Alt)

The Correct Answer is C ### Why Option C is Correct: The **breakdown of insulation** is widely considered the greatest single cause of electrical failures. Insulation is the primary barrier preventing unintended current paths (short circuits, ground faults) and ensuring the integrity of the electrical system. When insulation degrades (due to factors like age, heat, moisture, mechanical damage, or voltage surges), it compromises the system integrity, leading directly to catastrophic failures: * **Short Circuits and Ground Faults:** The degraded insulation allows current to bypass its intended path, creating arcs, excessive heat, and high fault currents, which cause equipment damage, tripping of protective devices, and sometimes fires. * **Aging:** Insulation failure is an irreversible process that dictates the effective lifespan of virtually all electrical equipment (motors, transformers, cables). ### Why the Other Options Are Incorrect: **A) overcurrent:** While overcurrent is a major failure mechanism, it is often a *symptom* of an underlying insulation failure (e.g., a short circuit caused by failed insulation leads to the massive overcurrent). Furthermore, healthy systems are protected against simple transient overcurrents by circuit breakers and fuses. Insulation breakdown, however, represents a fundamental and permanent loss of system integrity. **B) too frequent testing:** Testing, when performed correctly, is a preventative measure designed to *identify* potential failures, including insulation breakdown. There is no evidence that standard or even frequent non-destructive testing is a significant *cause* of widespread electrical failures. **D) high inductance:** Inductance is a natural and necessary property of AC electrical circuits (motors, transformers, transmission lines). While excessive inductance can cause power factor issues or voltage spikes in specific scenarios, it is an electrical characteristic, not a generalized root cause of component failure in the way that insulation breakdown is. Insulation breakdown is a material degradation issue that leads directly to catastrophic physical failure.