Electrician Red Seal · Question
During a routine inspection, a qualified worker observes significant localized heating at a bolted connection on a high-voltage busbar. What could be the most likely cause of this issue?
Localized heating at an electrical connection is typically caused by high contact resistance. This usually occurs due to loose connections (under-tightened), co
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Question: During a routine inspection, a qualified worker observes significant localized heating at a bolted connection on a high-voltage busbar. What could be the most likely cause of this issue?
Answer options:
- Over-tightened connection causing increased resistance ✅ Under-tightened or corroded connection leading to high contact resistance
- Excessive busbar length causing impedance rise
- Improper grounding of the busbar structure
Correct answer: Under-tightened or corroded connection leading to high contact resistance
Explanation: Localized heating at an electrical connection is typically caused by high contact resistance. This usually occurs due to loose connections (under-tightened), corrosion, or foreign material between the contact surfaces, which obstructs current flow and dissipates more energy as heat (I^2R losses). Improper grounding or excessive busbar length are less direct causes of localized heating at a specific connection point.
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