Circuit design quiz level 2's

What is the commonly used rule of thumb for selecting the correct cross-sectional area of a socket-outlet circuit?

• 1.5 mm² for lighting circuits and 2.5 mm² for other loads

• 2.5 mm² for lighting circuits and 1.5 mm² for other loads

• 1.0 mm² for lighting circuits and 2.5 mm² for other loads

• 2.5 mm² for all types of circuits

According to the worked example, what is the correct size of BS 3036 fuse required for a 6 kW load to be supplied at 230V by a PVC sheathed and insulated twin and earth copper cable?

• 20 amps

• 30 amps

• 26 amps

• 32 amps

What is the correct method to calculate the current-carrying capacity of a cable which is to be applied in a de-rated selection from the appropriate table in Appendix 4 of the BS 7671?

• Ca x Cg x Ci

• Ci x Ca x Cg

• Cg x Ci x Ca

• Ca x Ci x Cg

What is the maximum allowable voltage drop for lighting circuit?

• 4% of the nominal 230 volts

• 3% of the nominal 230 volts

• 5% of the nominal 230 volts

• 2.5% of the nominal 230 volts

What is the purpose of applying correction factors when calculating the current-carrying capacity of a cable?

• To ensure the cable can withstand high temperatures

• To adjust for the effects of grouping and ambient temperature

• To increase the cable's resistance to physical damage

• To comply with color coding standards for wiring

What is design current equal to?

• Size of protective device

• The load of a circuit divided by 230V

• Tabulated size of a conductor

• The current going through the circuit

What is the protective device greater than?

• The current carrying capacity of the circuits cable

• The load divided by the voltage

• The design current

• The current travelling through the circuit