Electrical Installations questions with
correct answers
What equipment is used in safe isolation - correct answer ✔✔ Locks and key
Proving units
Voltage indicators
Safety barriers
Warning signs and notices
State three protective measure against electric shock as given in BS7671 - correct answer ✔✔
Automatic disconnection of supply
Double or reinforced insulation
Extra low voltage system
What are three safety checks to be carried out on test equipment before they are used - correct
answer ✔✔ Check that there is no visible damage
Check the calibration certificate has not expired
Check if there is sufficient battery
Why should white PVC conduit not be used for external wiring systems - correct answer ✔✔ It
shouldn't be used outside since it is not conditioned for external influence. Direct sunlight
degrades it
What are three areas of responsibility to be signed for an Electrical Installation Certificate by
competent persons - correct answer ✔✔ Designer
Constructor
, Inspection and Testing
Explain the consequences if a measured earth fault loop impedance value is higher than that
permitted by BS7671 - correct answer ✔✔ The consequence of a high measured Zs is that, in an
event of an earth fault, the protective device may delay to operate because the high Zs will
generate a low prospective fault current Ipf
State the three principles of space heating - correct answer ✔✔ Conduction method: This is the
transfer of heat through solids
Convection method: This is the transfer of heat with the use of liquid or gas
Radiation method: This is the transfer of heat through air
How can we ensure safe isolation equipment is safe to use - correct answer ✔✔ Exposed metal
is not exceeding 4mm
Fused(usually 500mA)
Colour coded
Probes with finger barriers
Approved test equipment
What is PPE that are used in electrical work - correct answer ✔✔ Safety helmets
Gauntlets
Goggles
Safety Boots
Overalls
correct answers
What equipment is used in safe isolation - correct answer ✔✔ Locks and key
Proving units
Voltage indicators
Safety barriers
Warning signs and notices
State three protective measure against electric shock as given in BS7671 - correct answer ✔✔
Automatic disconnection of supply
Double or reinforced insulation
Extra low voltage system
What are three safety checks to be carried out on test equipment before they are used - correct
answer ✔✔ Check that there is no visible damage
Check the calibration certificate has not expired
Check if there is sufficient battery
Why should white PVC conduit not be used for external wiring systems - correct answer ✔✔ It
shouldn't be used outside since it is not conditioned for external influence. Direct sunlight
degrades it
What are three areas of responsibility to be signed for an Electrical Installation Certificate by
competent persons - correct answer ✔✔ Designer
Constructor
, Inspection and Testing
Explain the consequences if a measured earth fault loop impedance value is higher than that
permitted by BS7671 - correct answer ✔✔ The consequence of a high measured Zs is that, in an
event of an earth fault, the protective device may delay to operate because the high Zs will
generate a low prospective fault current Ipf
State the three principles of space heating - correct answer ✔✔ Conduction method: This is the
transfer of heat through solids
Convection method: This is the transfer of heat with the use of liquid or gas
Radiation method: This is the transfer of heat through air
How can we ensure safe isolation equipment is safe to use - correct answer ✔✔ Exposed metal
is not exceeding 4mm
Fused(usually 500mA)
Colour coded
Probes with finger barriers
Approved test equipment
What is PPE that are used in electrical work - correct answer ✔✔ Safety helmets
Gauntlets
Goggles
Safety Boots
Overalls
