Linergy power distribution blocks are for terminating wires and are designed to NEMA standards. This one pole block has one lug opening on the line (main) side and one lug opening on the load (branch) side. The line side lug is rated to accept one #4 to 600 kcmil copper or aluminum wire. The load side lug is rated to accept one #4 to 600 kcmil copper or aluminum wire. The lugs are made of aluminum. The lugs are rated for 420 amperes with copper wire and 340 amperes with aluminum wire. The lugs are rated to 600 volts. The housing is made of general purpose phenolic. These Linergy power distribution blocks are UL component recognized and CSA certified.