Which factor increases box fill when counting devices inside a box?

Which factor increases box fill when counting devices inside a box?

• A. Subtracting for each device.
• B. Adding one for each internal clamp or device yoke.
• C. Ignoring clamps entirely.
• D. Counting temperature rating.

Answer: (B)

Box fill is about how much space inside a box is needed to safely accommodate all the conductors and devices that occupy it. For every conductor that comes from outside the box and is terminated or spliced inside, count one unit of fill. All the equipment grounding conductors together count as one unit. In addition, any internal clamp and every device yoke that is mounted inside the box count as one unit each. That's why adding one for each internal clamp or device yoke increases the total box fill. Subtracting for devices would underestimate the space, ignoring clamps would miss part of the occupancy, and temperature rating doesn't affect box fill calculations.

Box fill is about how much space inside a box is needed to safely accommodate all the conductors and devices that occupy it. For every conductor that comes from outside the box and is terminated or spliced inside, count one unit of fill. All the equipment grounding conductors together count as one unit. In addition, any internal clamp and every device yoke that is mounted inside the box count as one unit each. That's why adding one for each internal clamp or device yoke increases the total box fill. Subtracting for devices would underestimate the space, ignoring clamps would miss part of the occupancy, and temperature rating doesn't affect box fill calculations.