Standard Power Distribution Blocks With High Short-Circuit Current Ratings

The requirements of the 2005 National Electric Code (NEC) and UL508A now require many electrical panels to carry a Short Circuit Current Rating (SCCR). Analyzing the SCCR of individual components and overcurrent protection devices is a method of determining the SCCR of an electrical assembly.

Marathon’s Power Distribution Blocks are standard products that have been used in
electrical control panels for over 35 years. These blocks have now been tested and approved for higher SCCR. The higher ratings are based on proper wire sizes and the appropriate circuit protection device. UL508A does allow default SCCR for Power Distribution Blocks of 10,000A with no additional testing.

Marathon’s Power Distribution Blocks (UL File # E62806) are recognized under UL
Standard 1059 and have been investigated by UL for Short-Circuit Current Ratings (SCCR) as described in the UL Guide Information for category XCFR2; Terminal Blocks-Component.

Marathon's new Power Distribution Blocks (UL File # E309401) are listed to UL 1953. The feeder spacing requirements of UL508A are achieved with these blocks.

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