Specialist Electrical Activities

What is 'isolation' in the context of electrical work?

• ATurning off lights
• BSeparating electrical equipment from all sources of electrical energy by physical and/or electrical means✓
• CJust unplugging
• DSwitching off

Answer: Isolation is the physical and/or electrical separation of equipment from live parts. This includes circuit breaker isolation, lockable disconnects, and physical barriers.

What is a 'permit to work' system in electrical work?

• AJust permission to work
• BFormal system authorizing high-risk tasks with documented controls and precautions✓
• COptional
• DJust for training

Answer: A permit to work documents: work scope, hazards identified, control measures, isolation steps, testing confirmation, authorized personnel, and rescue arrangements.

What is 'live working' in electrical terms?

• AWorking when awake
• BWork on equipment that remains energized (not isolated)✓
• CJust working at a live site
• DNormal electrical work

Answer: Live working means work on electrical equipment while it remains connected to the supply (not isolated). It's high-risk and requires special authorization and precautions.

What is 'arc flash'?

• ALightning
• BDangerous event where electrical current arcs across a gap producing extreme heat and blast✓
• CA spark
• DA light effect

Answer: Arc flash is a dangerous electrical event where current jumps a gap (arc), producing temperature >3000°C, blast pressure, molten metal spray, and severe burns.

What protective equipment should be worn for arc flash hazard?

• AJust regular clothes
• BArc-rated clothing, face shield, insulated gloves, safety glasses✓
• CNot needed
• DOnly a hat

Answer: Arc flash protection: arc-rated clothing (rated for flash severity), face shield, arc-rated gloves, insulated shoes, and safety glasses to protect against heat/light/pressure.

What is 'earth fault loop impedance' (EFLI) testing?

• ATesting for water leaks
• BMeasurement of impedance in earth fault path to verify RCD effectiveness✓
• CTesting soil
• DA type of wire test

Answer: EFLI testing measures the impedance of the path for earth fault current, confirming that RCD will operate within specified time (typically <300ms for general use).

What is 'insulation resistance testing'?

• AJust visual inspection
• BMeasurement using megohmmeter to verify insulation integrity of cables and equipment✓
• CTesting paint
• DNo such test

Answer: Insulation resistance testing uses a megohmmeter (1000V usually) to verify that insulation hasn't degraded and provides adequate protection against short circuits and shock.

What is 'continuity testing' used for?

• AJust checking if power works
• BVerifying that protective conductors (earth wires) provide continuous conductive path✓
• CTesting how long things work
• DNo purpose

Answer: Continuity testing verifies that protective conductors, bonding, and earthing are continuous and have sufficiently low resistance to carry fault current safely.

What is a 'test instrument' and why is accuracy important?

• AAny tool used in work
• BCalibrated device for measuring electrical parameters; accuracy is critical for safety verification✓
• CFor entertainment
• DNot important

Answer: Test instruments (multimeters, megohmmeters, earth testers) must be regularly calibrated to ensure accuracy. Inaccurate readings could miss dangerous faults.

What does 'lock off tag out' (LOTO) involve in electrical work?

• AJust locking a door
• BIsolating equipment, applying physical locks and tags to prevent accidental energization✓
• CJust tagging
• DNot necessary

Answer: LOTO: isolate equipment from supply, apply physical locks that only the authorized worker can remove, and attach warning tags explaining the lock-off reason.

What is 'competency' for electrical testing?

• AJust having a tool
• BKnowledge of standards, testing methods, equipment operation, and ability to interpret results safely✓
• CNot necessary
• DJust training once

Answer: Testing competency requires: understanding BS 7671/18th Edition, knowledge of testing standards, instrument operation, ability to interpret results, and recent practical experience.

What is the purpose of a 'temporary electrical installation' on construction sites?

• ATo power the site
• BTo safely provide power while minimizing hazards through proper design and protection✓
• CJust any power
• DNo safety concerns

Answer: Temporary site installations (UK construction regs) must: be on an RCD, use suitably robust equipment, minimize long cable runs, and be properly inspected/tested regularly.