Which table in the Code shows the maximum number of conductors permitted in a given size box?

• A. Table 314.16(A)
• B. Table 300.15
• C. Table 310.16
• D. Table 334.10

Answer: (A)

Figuring out how many conductors you can put into a box is all about box fill. Each conductor, plus any internal clamps and the grounding conductors counted together, takes up part of the box’s cubic inch capacity. To know the limit, you convert the box’s volume into a maximum conductor count using the box-fill table. The table that provides this maximum number of conductors for a given box size is Table 314.16(A). It ties cubic inches to how many conductors are allowed, taking into account the various counting rules. The other tables handle different topics—ampacity of conductors (Table 310.16), temperature adjustments for ampacity (Table 300.15), or NM cable installation specifics (Table 334.10)—so they aren’t used to determine how many conductors a box can contain.