UL 67 allows for a bulletin or manual that lists all acceptable series rating combinations to be supplied with the panelboard.

UL 67 allows for a bulletin or manual that lists all acceptable series rating combinations to be supplied with the panelboard.

• A. True
• B. False
• C. Not specified
• D. Both

Answer: (A)

Series rating in panelboards allows a higher system short-circuit current to be protected by a listed combination of the panelboard with specific protective devices, rather than the panelboard needing its own higher SCCR. UL 67 permits a bulletin or manual that lists all acceptable series-rating combinations to be supplied with the panelboard, so installers have an official reference of which device combinations are approved. This documentation ensures the panelboard can be used safely in systems with higher fault current by documenting exactly which breakers or fuses and their ratings can be paired with it, along with any conditions such as ambient temperature or conductor sizes. When such a bulletin is provided, selecting a listed combination from it ensures the protection scheme is compliant and verified by the listing. Therefore, the statement is true.

Series rating in panelboards allows a higher system short-circuit current to be protected by a listed combination of the panelboard with specific protective devices, rather than the panelboard needing its own higher SCCR. UL 67 permits a bulletin or manual that lists all acceptable series-rating combinations to be supplied with the panelboard, so installers have an official reference of which device combinations are approved. This documentation ensures the panelboard can be used safely in systems with higher fault current by documenting exactly which breakers or fuses and their ratings can be paired with it, along with any conditions such as ambient temperature or conductor sizes. When such a bulletin is provided, selecting a listed combination from it ensures the protection scheme is compliant and verified by the listing. Therefore, the statement is true.