With ratings up to 2280 amps at 600 volts, UL Listing or recognition, and dozens of input/output combinations, Marathon Special Products has the NEMA Power Block you need!
These blocks are manufactured in either thermoplastic or phenolic and are panel mountable (or Din mount in the 132 series).
Accessories include marking strips and covers to fit all of your needs.
See the Data Sheets and Specs here: http://www.marathonsp.com/splicer-distribution-power-blocks.php
And they are made in Bowling Green, OH!