level 3 - 8202 Cable calcs. Qz01

What does the symbol I_z stand for?

• Current carrying capacity of a cable.

• Design current.

• Rating of protective device.

• Impedance.

What does I_n stand for?

• Design current.

• Rating of protective device.

• Nominal current.

• Current capacity of cable.

What is the max voltage drop for a domestic lighting circuit?

• 3%

• 5%

• 7%

• 8%

What is the max voltage drop for a commercial lighting circuit?

• 3%

• 5%

• 7%

• 8%

What is the max voltage drop for a socket ring main?

• 3%

• 5%

• 7%

• 8%

What page in BS7671 will you find the derating factor for a cable that is surrounded by thermal insulation

• 218

• 297

• 423

• 583

The correction factor Cc is for:

• Soil thermal resistivity.

• Circuits buried in the ground

• BS3036

• Grouping

The correction factor Cg is for:

• Soil thermal resistivity.

• Circuits buried in the ground

• BS3036

• Grouping

Reference method A is used for:

• Multicore cable in conduit in thermally insulated wall

• Multicore cable in conduit on wooden wall

• Multicore cable in flush cable trunking in floor

• Multicore cable directly in the ground

Reference method D is used for:

• Multicore cable in conduit in thermally insulated wall

• Multicore cable in conduit on wooden wall

• Multicore cable in flush cable trunking in floor

• Multicore cable directly in the ground