Treat symptom-based questions as structured diagnosis exercises. The safest method is usually the correct method.

保守点検（ほしゅてんけん / maintenance inspection）

ほしゅてんけん

Maintenance inspection

Many written questions describe symptoms. You need to identify likely cause, risk, and first safe action.

Fault-based questions often mention smell, intermittent operation, breaker trips, visible insulation damage, or unusual heating. Link each symptom to a likely mechanism: contact resistance, overcurrent, leakage, or insulation breakdown. Then choose actions that prioritize safety: isolate, verify, inspect, and test before restoration. This structure aligns with both exam logic and real electrical practice.

- 保守点検（ほしゅてんけん / maintenance inspection）
- 接触不良（せっしょくふりょう / poor contact）
- 絶縁抵抗（ぜつえんていこう / insulation resistance）
- 地絡（ちらく / ground fault）

Decision sequence: symptom -> likely fault mechanism -> safety-first action -> confirm by test.

Repeated leakage trips after rain may indicate moisture-related insulation deterioration. First action is safe isolation and testing, not repeated breaker reset.

Answers that prioritize immediate re-energization without verification are usually wrong in safety-focused prompts.

Confusing symptom relief with root-cause correction. A reset is not a repair.

Accurate diagnosis prevents repeat faults and protects people, property, and schedule.

A circuit trips intermittently and terminals show discoloration. What fault mechanism is most likely?

Poor contact causing local heating and unstable operation

Discoloration often indicates heat from resistance at a bad connection. Investigation and correction are required before re-energizing.