What Is a Strut Channel? 1-5/8-Inch Strut Channel Explained

A 1-5/8-inch strut channel is the standard metal framing channel, most often sized 1-5/8 in. x 1-5/8 in., that supports pipe, conduit, cable trays, and equipment.

For the full breakdown, see our best 1-5/8-Inch Strut Channel guide.

Two channels can look identical on a shelf and carry wildly different weight, because the label “1-5/8-inch strut channel” describes width, not strength. The same family covers solid and slotted profiles, 12- and 14-gauge steel, pre-galvanized and 304 stainless finishes, and shallow 1-5/8 in. x 13/16 in. versions. Knowing which one you’re holding — and what it’s rated for — decides whether your rack holds or fails.

This is the metal backbone behind most commercial pipe, conduit, and cable-tray support. Contractors call it strut, unistrut, or channel; suppliers list it by the inch. Below, the dimensions that actually matter, the finishes and gauges you’ll see, and how load ratings get decided so you buy the right SKU the first time.

What Does 1-5/8-Inch Strut Channel Actually Mean?

The “1-5/8-inch” figure refers to the channel’s width, and the most common standard profile measures 1-5/8 in. wide by 1-5/8 in. deep. That square-ish profile is what most people picture when they say strut channel.

But the same width also comes in a shallow profile — 1-5/8 in. x 13/16 in. — used where depth is tight, and in back-to-back configurations that double the material into a 1-5/8 in. x 1-5/8 in. footprint. Deeper and heavier variants still carry the 1-5/8-inch name because the width stays constant.

That’s the catch with buying by family name alone. A 1-5/8-inch label tells you the width and nothing about depth, gauge, slot pattern, or capacity. Verify each SKU before ordering.

Dimensions, Materials, And Load Ratings

Slot geometry drives compatibility, and most 1-5/8-inch products list 9/16 in. x 1-1/8 in. slots on 2-inch centers. Width, depth, slot size, and slot spacing together decide which strut nuts, brackets, and fittings will actually fit.

Materials and finishes track the job. Pre-galvanized carbon steel, often referenced to ASTM A653 with a G90 coating, handles most indoor and general-purpose work.

Gauge changes strength more than any other spec. Several 1-5/8 in. x 1-5/8 in. products list 12 gauge, while some 1-5/8 in. x 13/16 in. products run 14 gauge.

Load ratings vary widely with material, gauge, and whether the channel is solid or slotted. Those are different channels doing different jobs.

How Is Strut Channel Installed?

Installation starts with layout, not with the channel. Manufacturer-style guidance recommends a level, tape measure, and a chalk line or laser to mark hole positions, then anchor installation followed by fasteners tightened to the specified torque. Open Haydon’s mounting channel catalog for the accessory line-up.

Attach strut nuts, brackets, end caps, and bolts before lifting the channel into place. Assembling at bench height cuts overhead work and keeps small parts off the floor.

After mounting, check alignment with a spirit level or laser level, then tighten sequentially from the center outward. That order pulls the channel in evenly instead of loading one end first.

• Don’t force a misaligned channel into position with excess torque — the published guidance warns against it.
• Use non-compressible shims or washers on uneven surfaces rather than cranking the anchor tighter.
• Confirm fittings match the SKU’s width, depth, slot size, and slot spacing, not just the 1-5/8-inch width.

For most buyers, the reliable shortlist is a pre-galvanized 12-gauge solid channel for indoor strength, a shallow 1-5/8 in. x 13/16 in. slotted profile when depth is tight, and 304 stainless where corrosion decides the job. If you want to compare tested options before ordering, this roundup of the best 1-5/8-inch strut channel covers what holds up in practice.