When Should You Use Back-to-Back Cantilever Arms? A Practical Installer Guide
Cantilever arms are widely used to support cable tray, pipework, ducting and external equipment. However, in some installations, a single cantilever arm may not provide enough strength or stability. This is where back-to-back cantilever arms become the correct solution.
This guide explains when back-to-back cantilever arms should be used, what problems they solve on site, and how installers can choose the right configuration for safe and reliable support.
What Is a Back-to-Back Cantilever Arm?
A back-to-back cantilever arm is created by fixing two cantilever arms together in a mirrored configuration, forming a reinforced double-channel bracket. This design increases load capacity, stiffness and resistance to twisting compared to a single arm.
Back-to-back assemblies are commonly used where:
- Loads are heavier than standard containment
- Equipment projects further from the wall
- Vibration or movement is expected
- Long-term structural stability is critical
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1. Supporting Heavy Cable Tray or Ladder Systems
Large cable tray and ladder runs generate both vertical load and rotational force. When a single cantilever arm is used, this can cause deflection or twisting over time. Back-to-back cantilever arms provide a wider, more rigid support that helps reduce movement.
Typical use cases include:
- High-capacity power cable routes
- Industrial ladder tray installations
- Wide cable containment systems
2. Mounting Air Conditioning Condenser Units
External condenser units place high point loads on wall-mounted brackets, particularly when exposed to wind and vibration. In these situations, back-to-back cantilever arms help distribute the load more evenly and improve resistance to bending.
This is particularly important when:
- Condenser units are large or deep
- The wall structure requires load spreading
- Installations are exposed to weather and vibration
Direct Channel also supplies complete Air Condenser Wall Bracket Kits designed specifically for these applications.
View Condensing Wall Bracket Kits
3. Long Projection Installations
As the projection length of a cantilever arm increases, the leverage acting on the fixing points also increases. Back-to-back cantilever arms reduce flex by doubling the channel section and improving stiffness along the full length of the bracket.
This makes them suitable for:
- Ductwork that must clear obstacles
- Pipework with large offsets
- Equipment requiring extended reach from the wall
4. High-Vibration Environments
In HVAC and mechanical installations, vibration can loosen fixings and accelerate fatigue. Back-to-back cantilever arms help limit movement by providing a stronger and more stable support structure.
They are commonly used in:
- Plant rooms
- External mechanical installations
- Industrial environments with moving equipment
Single vs Back-to-Back Cantilever Arms: When to Upgrade
| Scenario |
Recommended Option |
| Light cable tray or pipework |
Single cantilever arm |
| Heavy containment or wide tray |
Back-to-back cantilever arms |
| AC condenser units |
Back-to-back cantilever arms or condenser bracket kit |
| Long projection distances |
Back-to-back cantilever arms |
Final Thoughts
Back-to-back cantilever arms are not required for every installation. However, when loads increase, projection distances extend or vibration becomes a concern, they provide a clear upgrade in strength and stability. By selecting the correct cantilever configuration, installers can build safer and longer-lasting support systems with confidence.
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