EL0018 - Topic 6 CCC

What is the minimum distance required to AVOID derating between two 4mm² single core cables installed on a perforated horizontal cable tray?

(Use Figure 1 in AS 3008)

• 8mm

• 4mm

• 2mm

• 16mm

What is the ambient air temperature that AVOIDS derating?

• 45°C

• 35°C

• 40°C

• 25°C

Answer explanation

AS 3008 - 3.5.3 & Table 27(1)

40°C

A single core cable is installed in an underground wiring enclosure at a depth of 1m. What is the derating factor?

(a)  

Answer explanation

AS 3008 - Table 28(2)

A twin + earth TPS cable is installed bunched on a surface with 3 other circuits. What is the derating factor for the circuits?

(a)  

Answer explanation

AS 3008 Table 22

4 Circuits in total

0.65 derating factor

Select the normal operating temperature for V-90 TPS cable

• 90°C

• 75°C

• 105°C

• 70°C

Answer explanation

AS 3008 Table 1

V-90 Cable is normally used at 75°C

Select the term that refers to Maximum Demand

• I_B

• I_N

• I_Z

Answer explanation

AS 3000 2.5.3.1

What is the minimum size of the protective earthing conductor for a 95mm² Aluminium XLPE single core cable installed underground?

• 25mm²

• 95mm²

• 35mm²

• 16mm²

Answer explanation

AS 3000 Table 5.1

Select the minimum size CB for an installation with a calculated maximum demand of 110 Amps

(a)  

Answer explanation

AS 3000 Table 8.1 OR Table B1 for CB ranges

A C.B. protected 4 core + E, 10 mm² V75 orange circular cable laid flat touching two other circuits on perforated cable tray. Select the current carrying capacity AFTER derating.

• 54A

• 47.52A

• 52.92A

• 44.28A

A submain to an out building is installed buried direct in the ground, single core XLPE 120 mm² Aluminium cables laid in trefoil spaced from another circuit by 300 mm at a depth of 0.5m. The cable is  C.B. protected.

Select the current carrying capacity AFTER derating.

• 277A

• 243.76A

• 231.3A

• 229.42A