BOLT-ON 'A' Hubs: Used as Interchangeable Hubs and for Square D Meter Sockets.
BOLT-ON 'B' Hubs for QO and Homeline load centers, safety switches and Square D Outdoor/Rainproof Devices. Square D equipment with "RB" suffix, designated Rainproof (NEMA 3R Rainproof Construction), utilizes bolt-on hubs listed below. "RB" devices will accept 3/4" through 2-1/2" bolt-on hubs without the use of reducers. Off-center conduit thread openings and elongated mounting holes provide quick and easy adjustment to eliminate costly conduit offsets and bends.