B-Line CABLE SUPPORT FITTING, SERIES 2,3,4&5, 3" / 4" HEIGHT, 12" WIDTH, 36" RADIUS, ALUMINUM

Aluminum. That matters on two counts for an electrical contractor: weight when you are hanging a run overhead by yourself, and corrosion behavior in damp or washdown areas where a plain steel fitting would need coating. If the rest of your run is steel tray, expect to deal with the dissimilar metal contact at the splice.

Order it as B-Line 4A-12-CSF36. The string reads out as the spec: 4 inch height, 12 inch width, cable support fitting, 36 inch radius. Quote the full designation rather than a description, since the 12 and the 36 are the two digits that change most often between fittings.

A cable support fitting like the 4A-12-CSF36 is there to carry and guide the cable through a change of direction at a fixed 36 inch radius, which is what keeps the bend radius of the conductors inside their allowable limit. If what your drawing actually calls for is a full tray bend section with matching side rails, that is a different item. Read the fitting callout on the riser diagram before you order.

B-Line publishes a spec sheet for the 4A-12-CSF36 that carries the dimensioned drawing, and it is linked from the product information. Pull it before you lay out hanger spacing on a 36 inch radius turn, since the fitting's arc length drives where your first support lands coming out of the bend.