Cable calculations

What is the correction factor for circuits installed on cable trays?

• 0.3

• 0.5

• 1.00

• 0.725

What is the maximum volts-drop for a 230v lighting circuit?

• 5%

• 3%

• 10%

• 7%

What does RCBO stand for?

• Residual Current Breaker with Overload

• Residual Current Circuit Breaker

• Residual Current Device

• Residual Current Breaker with Overload and Short-circuit protection

What is the correction factor for BS3036 fuses?

• 0.5

• 0.725

• 1.00

• 0.3

What is the maximum disconnection time for a TN system circuit above 32A?

• 5 sec

• 500mS

• 0.2 sec

• 0.4 sec

What is the maximum volts-drop for a 400v circuit?

• 7%

• 3%

• 5%

• 10%

What is the ambient temperature factor for room temperature?

• 0.5

• 0.725

• 1.00

• 0.3

What is the maximum disconnection time for a TT system circuit below 32A?

• 0.4 sec

• 0.2 sec

• 300mS

• 5 sec

What is the formula for voltage drop (Vd)?

• Vd = mV x In x m

• Vd = mV x A x m

• Vd = mV x design current x length

• Vd = mV x It x m

What is the rating of an RCD for additional protection?

• 10mA

• 50mA

• 20mA

• 30mA