Wiring Methods and Materials Flashcards

A conduit nipple 24 inches or shorter running between enclosures may be filled to what maximum percentage?

Answer: 60%

Chapter 9, Note 4 allows 60% fill for nipples no longer than 24 in.

What ampacity adjustment factor applies when a raceway has 4 to 6 current-carrying conductors?

Answer: 80%

Table 310.15(C)(1) requires an 80% adjustment for 4 to 6 current-carrying conductors.

A raceway passes from a heated interior into a refrigerated cold room. What does NEC 300.7(A) require?

Answer: Sealing the raceway to prevent warm air circulating to the colder section

NEC 300.7(A) requires raceways crossing temperature differences to be sealed so that warm air does not condense moisture in the cold section.

A cable runs through a bored hole in a wood stud. If the edge of the hole is less than 1-1/4 inches from the nearest edge of the stud, what protection is required?

Answer: A steel plate at least 1/16 inch thick

NEC 300.4(A)(1) requires a steel plate or sleeve at least 1/16 in thick when the bored hole is closer than 1-1/4 in to the edge.

Direct-buried conductors emerging from the ground must be protected by enclosures or raceways from the minimum cover depth up to what height above finished grade?

Answer: 8 feet

NEC 300.5(D)(1) requires protection from the minimum cover depth up to at least 8 ft above finished grade.

Type MC cable must generally be supported and secured at intervals not exceeding what distance?

Answer: 6 feet

NEC 330.30 requires MC cable to be secured at least every 6 ft and within 12 in of boxes.

What is the smallest conductor size generally permitted to be installed in parallel?

Answer: 1/0 AWG

NEC 310.10(G) permits conductors 1/0 AWG and larger to be run in parallel, with limited exceptions.