The splitter boxes & troughs NEMA 1, 3R, 4, 12 and 4X are designed for 600 V (max.) service of 3 to 4 wires, in ordinary locations.
1100 B / T | NEMA 1
They have mounting holes in the back, knockouts, bracket hinges and a provision for padlocking.
1412 B / T | NEMA 3R / 4, 12
They have four mounting holes and a screw cover.
1412 TSS | NEMA 4X
The stainless steel splitter boxes & troughs NEMA 4X have four mounting holes and a crew cover. There are no knockouts. The phenolic insulated splitter blocks are factory installed on an interior panel, which is mounted on welded studs.
The lugs or welded studs have removeable tops, which allows wires to be put into place easily.
There is a curled lip around all sides to increase rigidity and prevent water from entering the NEMA 4/12/4X enclosure when it is open.