Level 3 - 8202 Design Current Calculation Quiz 02

How is the design current (I) for a single-phase calculated?

• I = P × V

• I = P / V

• I = √3 × V × I_L × Cosφ

• I = V / P

What is the formula for calculating the design current (I_b) for a three-phase?

• I_b = P / V

• I_b = V / P

• I_b = √3 × V × I_L × Cosφ

• I_b = P × V × I_L

What does the size of a cable for an installation depend on according to BS 7671?

• The color and length of the cable

• The current rating of a cable under defined installation conditions

• The brand of the cable

• The type of insulation material used

According to BS 7671, which section defines the maximum permitted drop in voltage for cable selection?

• Section 525 with values in Appendix 4, Section 6.4

• Section 543 with values in Appendix 3, Section 5.2

• Section 550 with values in Appendix 5, Section 6.1

• Section 560 with values in Appendix 6, Section 6.3

Where are the earth fault loop impedance requirements specified for cable selection in BS 7671?

• Regulation Tables 41.2, 41.3, and 41.4

• Regulation Tables 41.5, 41.6, and 41.7

• Regulation Tables 42.1, 42.2, and 42.3

• Regulation Tables 43.1, 43.2, and 43.3

What must the cable carry in terms of current according to its design current, I_b?

• Half the load current

• The full load current

• A variable load current depending on the time of day

• The minimum load current

Which factor influences the current rating of a cable due to an increase in resistance?

• Cable length

• Cable color

• Surrounding temperature

• Cable flexibility

What is a consideration for the type and size of protection for a cable?

• The color of the cable

• The brand of the cable

• How long the cable will have to carry fault current

• The weight of the cable

Which of the following is NOT listed as a type of cable?

• PVC

• MIMS

• Copper conductors

• Fiber optic

According to BS 7671, which of the following relationships must be complied with for current-carrying capacity of a cable?

• I_b ≥ I_t ≤ I_z

• I_b ≤ I_n ≤ I_z

• I_b ≥ I_n ≥ I_z

• I_t ≤ I_b ≤ I_n