Which code sections deal with grounding provisions for nonmetallic boxes?

Which code sections deal with grounding provisions for nonmetallic boxes?

• A. Sections 250.4(A)(2) and 250.122
• B. Sections 250.148(B) and 310.4
• C. Sections 250.148(D) and 314.3 Exception No. 1
• D. None of the above

Answer: (C)

Grounding a nonmetallic box requires creating a bonding path to the equipment grounding conductor, since the plastic or nonconductive box itself won’t carry fault current. The rule that tells you how to bond a nonmetallic box when a device is mounted inside (and a metal path isn’t available) is 250.148(D), which covers using an internal bonding jumper to connect the box to the equipment grounding conductor. There’s also an exception in 314.3 No. 1 that lets the box be considered grounded if the device’s grounding means (such as the device yoke/grounding terminal) provides the grounding path to the EGC in the box. Together, these provisions specifically address grounding provisions for nonmetallic boxes. The other sections listed don’t focus on this grounding scenario.

Grounding a nonmetallic box requires creating a bonding path to the equipment grounding conductor, since the plastic or nonconductive box itself won’t carry fault current. The rule that tells you how to bond a nonmetallic box when a device is mounted inside (and a metal path isn’t available) is 250.148(D), which covers using an internal bonding jumper to connect the box to the equipment grounding conductor. There’s also an exception in 314.3 No. 1 that lets the box be considered grounded if the device’s grounding means (such as the device yoke/grounding terminal) provides the grounding path to the EGC in the box. Together, these provisions specifically address grounding provisions for nonmetallic boxes. The other sections listed don’t focus on this grounding scenario.