309A Wiring Methods and Materials 3

Question 1

What is the main purpose of using armoured cable (AC90) in a commercial installation?

Accepted Answer

To provide mechanical protection and grounding continuity

Answer

AC90 armoured cable provides mechanical protection through its interlocking aluminium armour and also serves as an equipment grounding path, combining two functions in one cable assembly.

Question 2

According to the CEC, what is the minimum trade size of conduit that may contain a No. 6 AWG conductor?

Accepted Answer

21 mm (3/4")

Answer

Based on CEC conduit fill tables, a minimum 21 mm (3/4") trade size conduit is required for a No. 6 AWG conductor to comply with fill requirements.

Question 3

What is the purpose of an expansion fitting in a PVC conduit run?

Accepted Answer

To accommodate thermal expansion and contraction

Answer

PVC conduit expands and contracts significantly with temperature changes. Expansion fittings allow the conduit to move without stressing joints or distorting the raceway.

Question 4

What is the minimum depth of a device box for a receptacle installation?

Accepted Answer

38 mm (1-1/2")

Answer

The CEC requires a minimum box depth of 38 mm (1-1/2") for device boxes to provide adequate space for conductor splicing, device mounting, and heat dissipation.

Question 5

When installing conductors in a vertical raceway, at what height intervals must they be supported?

Accepted Answer

According to CEC Table 12-18 based on conductor size

Answer

CEC Table 12-18 specifies support intervals for conductors in vertical raceways based on conductor size. Larger conductors require more frequent support due to their greater weight.

Red Seal Electrician 309A Practice Test

Red Seal Electrician 309A Practice Test

309A Wiring Methods and Materials 3