B-Line Eaton series imperial cable tray and ladder, 4" Height, 9.78" Length, 36" Width, 36" and 30" Tray widths, Series 2-5 straight reducer, Aluminum

It is the transition piece between two different tray widths in a straight run. The 4A-36-SR30 joins a 36 inch wide tray to a 30 inch wide tray, keeping the run on the same centerline. Use it where the cable fill drops off after a branch and you want to step the tray down instead of carrying full 36 inch width the whole way.

36 inch on the wide end and 30 inch on the narrow end. If your run steps from 36 down to 24 or 18, this is the wrong piece, you need the reducer built for that pair of widths.

9.78 inches of length along the run. Take that off your remaining straight section when you lay out the run, and set your support spacing so the reducer is not left hanging unsupported between hangers.

It carries CSA certification, which is what an inspector on a Canadian install will be looking for on the tray fittings.

Order Eaton B-Line model 4A-36-SR30. That number reads as 4 inch depth, aluminum, 36 inch wide end, straight reducer to 30 inch.

Aluminum is the usual pick where weight on the supports matters and where corrosion resistance is wanted without galvanizing. This fitting weighs 4 lb, so a single electrician can set it in place overhead. It also needs to match the rest of the run, mixing aluminum fittings into a steel tray run creates a dissimilar metal joint and the splice hardware will not correspond.