B-Line Eaton series imperial cable tray and ladder, 4" Height, 15" Length, 18" Width, Series 2-5 vertical tee down, Aluminum, 12" Radius

It's a three-way tray fitting that takes a horizontal run and drops a branch downward while the main run continues. The 4A-18-VT12 is built for 18 inch wide, 4 inch deep aluminum tray and turns the drop on a 12 inch radius, so conductors bend at a controlled radius instead of a sharp corner. Use it where you need to feed equipment below the main tray elevation without breaking the run.

This tee is aluminum. Aluminum tray and fittings are the usual pick where weight matters on the support spacing and where corrosion is a concern, including damp or coastal installs, and it needs no galvanizing or paint. Steel tray carries more load per span and is more common in heavy industrial work. The important part is not to mix: use aluminum fittings with aluminum tray so you avoid dissimilar metal contact at the splice.

Eaton B-Line part number 4A-18-VT12. Read it as 4 inch rail, aluminum, 18 inch width, vertical tee down, 12 inch radius, which is how the whole Series 2-5 fitting line is numbered. Quote that number and you get the exact fitting rather than a horizontal tee or a vertical elbow.

Order the splice plates and connection hardware separately. Cable tray fittings in this family are supplied as the formed fitting; each end that meets a straight section or another fitting needs a splice plate set with its bolts and nuts. Count your open ends before you order so the crew isn't short at the joint.

11.5 lb. That is light enough for one electrician to set on a ladder, but the fitting still needs hangers or trapeze supports on both sides of the transition, because a vertical drop puts an unbalanced load at the joint that the horizontal run's supports will not carry on their own.

The 4A-18-VT12 carries a CE marking. That is the only certification held on record for this fitting, so if your specification calls out a particular listing or load class for the tray system, verify it against the Series 2-5 system documentation for the full run rather than the individual fitting.

15 inches along the run, with the tray section itself 18 inches wide and 4 inches deep. Subtract that 15 inches from your straight section takeoff at the drop point, and allow for the splice plate laps on each side.