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What is the difference between a fully rated and a series rated panelboard?


Issue:
Application

Product Line:
Panelboards

Environment:
UL, NEMA

Cause:
An understanding of the difference between series and fully rated equipment is essential to any application when both are under consideration.

Resolution:

The short circuit current rating (SCCR) of a fully-rated system is equal to the lowest ampere interrupting rating (AIR) of any overcurrent protective device (main or branch) installed. Also, with a fully-rated system, individual devices can open at specified fault levels without affecting the remainder of system. Series-rated panelboards accomplish the interruption of high level overcurrents by using a combination of main and branch devices.  Consequently, for a series-rated panelboard a high level overcurrent on a branch circuit can result in the main device opening and interrupting power to all circuits served from the panelboard.  The chief attraction of a series-rated panelboard is a lower initial cost of equipment.


 
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