Installation Protection Quiz

What is the primary purpose of isolation in an electrical installation?

• To reduce voltage levels

• To cut off the installation from every source of electrical energy

• To protect against short circuits

• To provide emergency lighting

According to BS 7671, where should isolators be located?

• In areas accessible to ordinary persons

• Near the main consumer unit

• Where ordinary persons have no access

• At least 10 meters away from the load

Which of the following is NOT a concept identified by BS 7671 for installation protection?

• Isolation and switching

• Switching for mechanical maintenance

• Voltage regulation

• Emergency switching

What type of device is used for functional switching?

• Residual current device (RCD)

• Circuit breaker

• Light switch

• Fuse

What is the purpose of switching for mechanical maintenance?

• To disconnect faulty equipment permanently

• To allow non-electrically skilled persons to safely work on equipment

• To reduce the voltage supplied to machinery

• To isolate high-voltage equipment for inspection

Which of the following is an example of emergency switching?

• Light switch

• Stop button in a workshop

• A fuse protecting a circuit

• Timer-controlled switch

Semi-conductors may be used for switching in which concept?

• Emergency switching

• Isolation

• Functional switching

• Overcurrent protection

Overcurrent protection is primarily intended to guard against:

• Voltage fluctuations

• Unauthorized access to electrical installations

• Overload and fault currents

• Insulation failure

Overload currents are typically caused by:

• Faulty cables

• Short circuits

• Additional mechanical load on equipment

• Poor earthing arrangements

Fault current can best be described as:

• A long-term overload condition

• A short-term condition caused by faults in cables or equipment

• Excessive current due to circuit design

• Current that exceeds the capacity of the protective conductor