EETC Wiring Methods 3

Question 1

In a cable tray installation, what is the minimum width of a ladder-type cable tray for a 600V power cable with an outside diameter of 3.5 inches?

Accepted Answer

12 inches

Answer

NEC 392.22 requires single-conductor cables in ladder trays to maintain spacing and the tray width must accommodate the cable diameter; 12-inch trays accommodate most standard power cables.

Question 2

What NEC article governs the installation of electrical metallic tubing (EMT)?

Accepted Answer

Article 358

Answer

NEC Article 358 specifically covers the installation and use of electrical metallic tubing (EMT).

Question 3

A 'wet location' as defined by the NEC includes all of the following EXCEPT:

Accepted Answer

Indoor locations with controlled humidity below 50%

Answer

The NEC defines wet locations as those subject to weather, saturation, or underground exposure; controlled indoor humidity does not qualify as a wet location.

Question 4

When installing conduit through a fire-rated wall, what is required?

Accepted Answer

A firestop system listed for the opening

Answer

NEC 300.21 requires that penetrations of fire-rated walls be firestopped using approved materials or methods to maintain the fire rating.

Question 5

What is the maximum allowable fill percentage for a conduit containing three current-carrying conductors?

Accepted Answer

31%

Answer

NEC Table 1, Chapter 9 limits conduit fill to 40% for two conductors and 40% maximum, but with three or more conductors the fill is 40%; however, for conductors over 2, fill is limited to 40% per NEC—specifically 40% for 2 conductors and 40% for 3+, the standard answer for 3+ conductors is 40%.

(EETC) Electrical Technician Certification Practice Test

(EETC) Electrical Technician Certification Practice Test

EETC Wiring Methods 3