18th Edition Wiring Regulations Quiz

What is the difference between impedance and resistance?

• Impedance is measured on live circuits with alternating current, while resistance is measured on dead circuits with direct current

• Impedance is measured on dead circuits with direct current, while resistance is measured on live circuits with alternating current

• Impedance is measured in hertz, while resistance is measured in ohms

• Impedance is measured in ohms, while resistance is measured in hertz

What does a lower impedance indicate in terms of current flow?

• Lower impedance indicates lower current flow

• Lower impedance indicates higher current flow

• Lower impedance indicates no current flow

• Lower impedance indicates alternating current flow

What is the purpose of zs in electrical circuits?

• To measure the voltage in the circuit

• To regulate the frequency of the circuit

• To protect against the dangers of electric shock during a fault

• To determine the maximum current flow in the circuit

Where can the maximum disconnection time for safety be found in the wiring regulations book?

• Chapter 59

• Chapter 32

• Chapter 18

• Chapter 41

What is the maximum permitted disconnection time for a final circuit in a tn system with a nominal voltage of 230 volts?

• 0.2 seconds

• 0.4 seconds

• 0.6 seconds

• 0.8 seconds

What is the maximum permitted zs for a type b bs en 60898 circuit breaker of 32 amps in a final circuit?

• 1.37 ohms

• 1.50 ohms

• 1.25 ohms

• 1.10 ohms

What is the maximum permitted zs for a reduced low voltage circuit of 63.5 volts protected by a type c bs en 60898 circuit breaker?

• 0.40 ohms

• 0.70 ohms

• 0.60 ohms

• 0.50 ohms

What is the maximum permitted zs for a bs 88-3 fuse rated at 32 amps in a distribution circuit?

• 1.20 ohms

• 1.30 ohms

• 1.40 ohms

• 1.50 ohms

What does the c min factor of 0.95 adjust for in the zs figures?

• Voltage fluctuations

• Current fluctuations

• Temperature fluctuations

• Resistance fluctuations

What does regulation 411.3.2.3 specify if table 41.1 is not applicable or if it is a distribution system for a tn system?

• Allow a disconnection time of 5 seconds

• Allow a disconnection time of 2 seconds

• Allow a disconnection time of 3 seconds

• Allow a disconnection time of 1 second