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Module 7 — Maintenance Practices

7.4 — Potential Safety Hazards When Working with Electrical Systems and Protective Equipment

Practice questions test what you know. This note teaches what you don’t.

Question banks train recall. The questions that decide a pass are the borderline ones, where two answers look right — and those are won by understanding. That is what this note is written for.

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This section covers the hazards of working on or near electrical systems — electric shock, arc flash and arc blast, stored energy, batteries, electrostatic discharge and electromagnetic fields, and the conditions that make each of them worse — and the measures that control them: personal protective equipment, insulated tools, isolation and verification that voltage is absent. It entered the Module 7 syllabus with the EASA amendment supporting Regulation (EU) 2025/111 on the continuing airworthiness of electric- and hybrid-propulsion aircraft, applicable …

6 sections 5 worked examples 6 tables 5 tips 2 warnings

51 exam-style questions in our bank test this topic. This note teaches the theory behind every one of them.

What you will learn

  1. Electric shock hazards and effects of current on the human body
  2. Arc flash, arc blast, and stored energy hazards (capacitors, batteries, power electronics)
  3. Battery-related hazards: chemical, thermal runaway, fire and explosion risks
  4. Electrostatic discharge (ESD) and electromagnetic hazards
  5. Environmental and situational risks (wet conditions, confined spaces, poor accessibility)
  6. Protective measures: personal protective equipment (PPE), insulated tools, system isolation and verification of absence of voltage
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