Fully rated VS Series rated:
A “fully rated” system means that each overcurrent device is rated to handle the full fault current at its input terminals. In contrast, a “series rated” system might include components with lower short-circuit ratings than the actual fault current. This is allowed if the manufacturer provides documentation showing that the devices were tested together under fault conditions. The test proves that all devices in the circuit can protect the system, reset properly, and work as intended after the fault.
Series rated is acceptable under NEC 240.84.
Make sure to add a note in plans that per NEC 110.22 the electrical contractor should ensure specific marking on each piece of equipment containing an over current device used in the series combination. This marking should be readily visible and state the following.
“CAUTION-SERIES COMBINATION SYSTEM RATED ______ AMPERS. IDENTIFIED REPLACEMENT COMPONENT REQUIRED.”
Sample of Series rated- SLD