TN LLE Conductors and Cables 2

Question 1

Per NEC Table 310.16, what is the ampacity of a 12 AWG THHN copper conductor at 30 degrees C ambient?

Accepted Answer

30 amperes

Answer

NEC Table 310.16 lists 12 AWG THHN copper at 30 amperes in the 90 degrees C column.

Question 2

What is the maximum number of 12 AWG THHN conductors permitted in a 3/4-inch EMT conduit per NEC Chapter 9?

Accepted Answer

12

Answer

Per NEC Chapter 9, Annex C, Table C1, a 3/4-inch EMT can hold up to 12 conductors of 12 AWG THHN.

Question 3

Per NEC 310.15(C)(1), what ampacity adjustment factor applies when 7-9 current-carrying conductors are in a single conduit?

Accepted Answer

70%

Answer

NEC Table 310.15(C)(1) requires a 70% ampacity adjustment when 7-9 current-carrying conductors share a raceway.

Question 4

What is the minimum burial depth for UF cable installed under a residential driveway per NEC Table 300.5?

Accepted Answer

24 inches

Answer

Per NEC Table 300.5, direct-buried UF cable under a one- and two-family dwelling driveway requires a minimum cover of 24 inches.

Question 5

Per NEC 334.80, what limitation applies to NM cable when installed in thermal insulation?

Accepted Answer

Ampacity must be based on the 60 degrees C conductor rating

Answer

NEC 334.80 requires that the ampacity of NM cable installed in thermal insulation be based on the 60 degrees C conductor temperature rating.

TN LLE - Tennessee Limited Licensed Electrician Practice Test