Strut Channels: What They Are, How They Work & Connect

How to Connect Strut Channels

Connecting strut channels is the core skill in any strut-based installation. The system is intentionally tool-light: a socket wrench, a level, and the correct fittings are all that is typically required.

Spring Nuts and Bolts — The Foundation Connection

Every strut fitting attaches via a spring nut (also called a channel nut or T-nut). The standard process:

• Insert the spring nut into the channel slot at a 45-degree angle.
• Rotate 90 degrees so the nut tabs engage the channel lips — you will feel a positive snap.
• Position the fitting over the nut location and thread in the bolt (typically M10 or 3/8-in UNC).
• Torque to the manufacturer's specification — typically 20–25 Nm for M10 carbon steel, 18–22 Nm for stainless to prevent galling.

Channel-to-Channel Connections (In-Line Splicing)

To extend a channel run end-to-end, use a splice plate fitting (also called a channel connector or fish plate). Splice plates straddle both channel ends and are bolted through the slots. For structural continuity, use a minimum 150 mm overlap with two bolts per side. For non-structural runs (cable management only), single-bolt splice connectors are acceptable.

Right-Angle and Cross Connections

90-degree flat plate fittings connect two channels in the same plane (T-junction or cross). Angle brackets (standard 90-degree gusset plates) connect channels in perpendicular planes — for example, a horizontal run meeting a vertical drop. Combination angle fittings allow 3D frame construction without any welding or drilling.

Channel to Structure — Anchoring

• Concrete: Use a channel insert cast into the slab, or post-install wedge anchors / chemical anchors through the channel back holes. Minimum embedment per anchor manufacturer's ETAG/ICC-ES evaluation.
• Steel beam / purlin: Use beam clamps that grip the flange — no drilling into structural steel required.
• Threaded rod hanger: Pipe hanger channel is suspended from threaded rod (M10, M12, or 3/8-in / 1/2-in) via a threaded rod coupling nut into the back of the channel or via a top-mounted bracket.
• Wall surface: Flat back-plate brackets or direct-mount base plates bolt through the channel back and into the wall substrate using appropriately rated anchors.

Building a Free-Standing Frame

Free-standing strut frames — common for equipment support, pipe racks, and solar ground mounts — use four vertical channels as posts connected by horizontal rails at top and mid-height. Post base plates are bolted to the floor. Diagonal bracing channels, attached with 45-degree fitting plates, provide lateral stability. A 1.0 m x 1.0 m x 2.0 m tall frame using 41 x 41 mm 2.0 mm gauge channel can carry a uniformly distributed load of approximately 400–600 kg at the top rail, depending on bracing configuration and anchor design.

Torque and Assembly Tips

• Always use a calibrated torque wrench for structural connections — finger-tight plus a quarter-turn is not adequate for load-bearing joints.
• Apply anti-galling compound (or use waxed nuts) when assembling stainless-to-stainless connections to prevent thread seizure.
• Check that spring nuts are fully rotated and engaged before applying load — a nut rotated only 45 degrees has less than 30% of its rated capacity.
• For vibration environments (HVAC, machinery bases), use serrated flange nuts or thread-locking compound on the bolt threads.
• When cutting channel to length in the field, use a metal-cutting saw or angle grinder — never a torch, as heat destroys the galvanized coating at the cut end. Touch up cut ends with cold-galvanizing compound.