B-Line Eaton series open racks, Steel, Telco gray powder coat, 12-24 panel mounting holes, 42 mounting spaces, Top channel style, Seismic Zone 4, ope

The SB5857090TG gives you 42 mounting spaces on a 90 inch tall frame, which is the standard full-height open rack size for a telecom or data room. Plan your equipment layout against 42U of usable space, and remember an open frame has no doors or side panels, so cooling comes from the room rather than from the rack itself.

Rails on this B-Line open rack are punched with 12-24 panel mounting holes, so equipment mounts with 12-24 screws directly into the tapped holes. No cage nuts and no square-hole hardware. If your servers or patch panels shipped with M6 or 10-32 hardware, you will need to swap to 12-24 screws.

It is built as a Seismic Zone 4 open duct unequal flange rack, which is the highest seismic zone classification and the one specified for California and similar high-activity regions. The frame is ASTM A570 grade 33 steel. Anchoring to the slab and any overhead bracing still has to follow the engineer's detail for the room.

Footprint works out from a 23 inch width and 90 inch length/depth dimension, with the frame standing 90 inches tall. Add your own service clearance front and rear, since an open frame is worked from both sides and cabling runs off the top channel.

Unequal flange means the rail flanges are different depths, which gives you a deeper mounting surface on one side for heavier gear and room to dress cable on the other. Open frame racks like this one suit telecom closets, cross-connect fields, and patch-heavy rooms where you want full access from both sides and no airflow restriction. If you need physical security, dust control, or contained hot/cold aisle airflow, an enclosed cabinet with doors is the right choice instead.

It is a top channel style frame, meaning the uprights are tied together at the top with a channel that ladder rack and runway are commonly landed on. The open duct design is built around routing cable vertically through the frame rather than inside a closed body.

Yes, the rack carries a UL Listed marking, which matters if your AHJ or facility spec requires listed support structure in a communications or equipment room.

The frame is steel with a Telco gray powder coat, the standard gray used across B-Line open frame racks, so it lines up with existing telco-gray racks and runway in a shared room. Powder coat over steel also holds up better to cart knocks and rack-and-stack traffic than a painted finish.

Bare frame weight is 81.71 lb, so two people can carry it up a stairwell or through a corridor without equipment. That is the empty rack only, before rails hardware, cable management, or gear.