Square D® NF Merchandised Panelboards MH44, is a enclosure steel panelboard box has NEMA1 degree of protection, cULus certified. Warranty period is 18 month. This is a powerbus accessory is standard hanger for the busway rated at 400 A. Square D® NF Merchandised Panelboards MH44, is a enclosure steel panelboard box has NEMA1 degree of protection, cULus certified. Warranty period is 18 month. This is a powerbus accessory is standard hanger for the busway rated at 400 A.