Voltage Drop Measuring

What is the formula for calculating voltage drop according to the text?

• Voltage Drop = L x Ib / (mV/A/m)

• Voltage Drop = Ib / (mV/A/m) x L

• Voltage Drop = (mV/A/m) + Ib + L

• Voltage Drop = (mV/A/m) x Ib x L / 1000

Where can you find the value for (mV/A/m) needed to calculate voltage drop?

• The index of BS7671:2018

• The main text of BS7671:2018

• Appendix 4 of BS7671:2018

• The preface of BS7671:2018

What does 'Ib' represent in the voltage drop calculation?

• The design current

• The length of the circuit

• The voltage of the circuit

• The resistance of the circuit

How is the design current (Ib) usually calculated?

• Voltage divided by resistance

• Voltage times current

• Watts divided by voltage

• Current times resistance

What does 'L' represent in the voltage drop calculation?

• The length of the circuit in metres

• The load of the circuit in watts

• The luminosity of the circuit

• The lag of the circuit in seconds

For which systems does BS7671:2018 not provide voltage drop values?

• Overhead cable systems

• Underground cable systems

• Power track and lighting trunking systems

• Domestic lighting systems

What is the voltage drop for a multi-core 70 degrees C thermoplastic non-armoured cable with 2.5 mm conductors supplying a single-phase load of 20 amp at 230 volts over 22m?

• 10.00V

• 9.00V

• 8.22V

• 7.92V

Where in the BS7671:2018 can you start looking for the current carrying capacities and voltage drop for cables?

• Appendix A

• Table of tables on page 522

• The glossary

• Chapter 5

What is the correct table for finding the voltage drop of a multi-core 70 degrees C thermoplastic non-armoured cable with 2.5 mm conductors?

• Table 2B on page 202

• Table 4D2B on page 404

• Table 3C on page 305

• Table 6A on page 600

What is the value of (mV/A/m) for a 2.5 mm sq conductor of a multi-core 70 degrees C thermoplastic non-armoured cable?

• 18 mv/A/m

• 24 mv/A/m

• 20 mv/A/m

• 22 mv/A/m