B-Line Eaton series imperial cable tray and ladder, 4" Height, 36" Length, 18" Width, 18" and 36" Tray widths, Series 2-5 horizontal expanding tee, Al

Model 4A-18-36-HT24 is built to join an 18 inch wide run to a 36 inch wide run, which is what the "expanding" in horizontal expanding tee means. The fitting itself is listed at 18 inches wide, and the tray widths it serves are 18 inch and 36 inch. If both legs of your tee are the same width, you want a straight horizontal tee instead, not the expanding version.

Yes, the 4A-18-36-HT24 expanding tee is UL Classified. That matters where the tray is being used as an equipment grounding conductor and where an inspector wants classified fittings through the whole run, not just on the straight sections.

Allow 36 inches along the length of the fitting, with the 18 inch leg width and the 24 inch radius sweep to the branch. At 4 inches high it drops the same as a 4 inch deep tray. Lay out the 36 inch dimension plus your straight-section cut before ordering supports, since the 24 inch radius carries the turn well past the tray edge.

It weighs 27.92 lb bare. That is a one-man lift on the ground but awkward overhead at 36 inches long, so plan a second set of hands or a lift for high ceilings. Add the fitting weight plus cable fill when you size the hangers either side of the tee.

Order Eaton B-Line part number 4A-18-36-HT24. The code reads out as 4 inch height, aluminum, 18 inch and 36 inch tray widths, horizontal tee, 24 inch radius. Splice plates and hardware are separate line items on cable tray fittings, so confirm you have those on the order too.

Aluminum keeps the weight down (this tee is 27.92 lb) and handles damp and mildly corrosive interior and exterior environments without paint or galvanizing. For a run already built in aluminum tray you should stay in aluminum through the fittings anyway, both for the splice fit and to avoid dissimilar metal contact at the joint.