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Electrician Red Seal · Question

An electrician is installing a new 20 A, 120 V circuit for wall receptacles in a dwelling unit. Which of the following grounding conductors is permissible for this circuit, assuming the wiring method is NMD90 (non-metallic sheathed cable)?

For a 20 A circuit, #12 AWG copper conductors are typically used. The bare copper wire integral to NMD90 cable serves as the equipment grounding conductor and m

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Question: An electrician is installing a new 20 A, 120 V circuit for wall receptacles in a dwelling unit. Which of the following grounding conductors is permissible for this circuit, assuming the wiring method is NMD90 (non-metallic sheathed cable)?

Answer options:

  • An insulated #14 AWG copper wire ✅ The bare #12 AWG copper wire integral to the NMD90 cable
  • The metallic armour of an AC90 cable
  • A separate #10 AWG copper wire run alongside the NMD90

Correct answer: The bare #12 AWG copper wire integral to the NMD90 cable

Explanation: For a 20 A circuit, #12 AWG copper conductors are typically used. The bare copper wire integral to NMD90 cable serves as the equipment grounding conductor and must be sized according to Table 16 in the CEC, which permits #12 AWG for 20 A circuits. Options A and D are incorrect sizing or methods for this application, and C is for a different cable type.

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