Which NEC sections require legible field marking of equipment enclosures for circuit breakers or fuses applied in compliance with series combination ratings?

Which NEC sections require legible field marking of equipment enclosures for circuit breakers or fuses applied in compliance with series combination ratings?

• A. 240.86
• B. 240.86(A)
• C. 110.22(B) and (C)
• D. 110.15

Answer: (C)

Legible field markings on equipment enclosures are required so that anyone installing or inspecting the panel can immediately see and understand how the protective device is applied, especially when a series-rated arrangement is used. When a circuit breaker or fuse arrangement is rated in series, the enclosure must clearly display that rating in a way that remains readable during normal service. This is addressed by the NEC provisions in 110.22(B) and 110.22(C), which specify that required markings must be legible, conspicuous, and accessible, so the information about the series-rated configuration is always clear to personnel. Other sections mentioned in the choices deal with different labeling and installation requirements and do not specifically mandate the legible field markings for series-rated enclosures. That makes the combination of 110.22(B) and 110.22(C) the appropriate reference for this requirement.

Legible field markings on equipment enclosures are required so that anyone installing or inspecting the panel can immediately see and understand how the protective device is applied, especially when a series-rated arrangement is used. When a circuit breaker or fuse arrangement is rated in series, the enclosure must clearly display that rating in a way that remains readable during normal service. This is addressed by the NEC provisions in 110.22(B) and 110.22(C), which specify that required markings must be legible, conspicuous, and accessible, so the information about the series-rated configuration is always clear to personnel.

Other sections mentioned in the choices deal with different labeling and installation requirements and do not specifically mandate the legible field markings for series-rated enclosures. That makes the combination of 110.22(B) and 110.22(C) the appropriate reference for this requirement.