CME NEC Code and Theory 3

Question 1

Under NEC 250.66, the size of the grounding electrode conductor for a copper service entrance conductor sized at 2/0 AWG is determined by which table?

Accepted Answer

Table 250.66

Answer

NEC Table 250.66 is used to determine the minimum size of the grounding electrode conductor based on the largest service-entrance conductor.

Question 2

NEC 430.52 requires branch-circuit short-circuit and ground-fault protection for motors. For an inverse time circuit breaker protecting a Design B squirrel-cage motor, the maximum rating is what percentage of full-load current?

Accepted Answer

250%

Answer

NEC Table 430.52 allows inverse time circuit breakers for Design B squirrel-cage motors to be rated up to 250% of the motor's full-load current.

Question 3

According to NEC 358.20, what is the minimum trade size for Electrical Metallic Tubing (EMT)?

Accepted Answer

1/2 inch

Answer

NEC 358.20 specifies that the minimum trade size for EMT is 1/2 inch (metric designator 16).

Question 4

Which NEC article governs the installation of electrical systems in hazardous (classified) locations using the Zone equipment classification system?

Accepted Answer

Article 505

Answer

NEC Article 505 covers Class I, Zone 0, 1, and 2 hazardous locations using the Zone classification system.

Question 5

NEC 240.4(D) limits overcurrent protection for small conductors. What is the maximum OCPD permitted for 14 AWG copper conductors?

Accepted Answer

15 amperes

Answer

NEC 240.4(D)(3) limits overcurrent protection for 14 AWG copper conductors to a maximum of 15 amperes.

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CME NEC Code and Theory 3