309A Canadian Electrical Code 4 — Questions and Answers
Question 1: What does CEC Rule 10-204 require regarding the connection of the grounding electrode conductor?
- It may be spliced at any point
- It must be continuous without splice (Correct answer)
- It may use wire nuts for connections
- It must be installed in conduit
Correct answer: It must be continuous without splice
CEC Rule 10-204 requires that the grounding electrode conductor be installed as a continuous conductor without splice to maintain a reliable, low-impedance path to earth.
Question 2: According to the CEC, what is the minimum insulation resistance that must be measured before energizing a new installation?
- 500 kΩ
- 1 MΩ (Correct answer)
- 5 MΩ
- 10 MΩ
Correct answer: 1 MΩ
The CEC requires a minimum insulation resistance of 1 MΩ measured between conductors and between each conductor and ground before a new electrical installation can be energized.
Question 3: Under the CEC, what is the demand factor applied to the first 5000 W of a residential electric range load?
- 50%
- 60%
- 70%
- 100% (Correct answer)
Correct answer: 100%
CEC Table 62 applies a 100% demand factor to the first 5000 W of a residential electric range, meaning the full load must be included in the service calculation.
Question 4: What minimum conductor size does the CEC require for a feeder supplying a dwelling unit with a calculated load of 100 A?
- No. 3 AWG copper (Correct answer)
- No. 2 AWG copper
- No. 1 AWG copper
- No. 1/0 AWG copper
Correct answer: No. 3 AWG copper
According to CEC ampacity tables, No. 3 AWG copper conductor with 90°C rated insulation, corrected for a 75°C termination, can carry 100 A for a dwelling unit feeder.
Question 5: According to the CEC, how many branch circuits are required as a minimum for a dwelling unit kitchen?
- 1 circuit
- 2 circuits (Correct answer)
- 3 circuits
- 4 circuits
Correct answer: 2 circuits
CEC Rule 26-724 requires a minimum of two small appliance branch circuits to supply kitchen counter receptacles in a dwelling unit, ensuring adequate capacity for simultaneous appliance use.
Question 6: What does CEC Rule 12-100 require regarding the use of NMD90 cable?
- It may be used in any location
- It is restricted to dry locations within buildings (Correct answer)
- It may be used underground without protection
- It may be used in hazardous locations
Correct answer: It is restricted to dry locations within buildings
CEC Rule 12-100 restricts NMD90 (non-metallic dry) cable to dry locations within buildings, as it lacks the protection needed for wet, damp, or exposed installations.
309A Canadian Electrical Code 4
What does CEC Rule 10-204 require regarding the connection of the grounding electrode conductor?