Crossarm Mounting Bracket
- Secures the crossarm to the pole top — the primary structural connection between arm and pole
- Standard, heavy-duty, and double-arm variants (120×80 to 150×100 mm plate)
- Hot-dip galvanized to ASTM A-123 (≥86 μm)
- ANSI C135.6 mounting hole pattern
Technical Specifications
| Catalog No. | Type | Plate Section | Bolt | Weight (kg) | Surface |
|---|---|---|---|---|---|
| RAX-CMB-S | Standard Duty | 120×80×6 | M16 | 1.2 | HDG |
| RAX-CMB-H | Heavy Duty | 150×100×8 | M20 | 2.5 | HDG |
| RAX-CMB-D | Double Arm | 2×150×100×8 | M20 | 5.0 | HDG |
Application & Installation
Where it is used
- Primary connection between the crossarm and the pole, all distribution voltages
- Heavy-duty configurations for transmission crossarms (RAX-CMB-H)
- Double-arm dead-end construction (RAX-CMB-D pairs with Double Arming Plate)
- Substation egress poles with multiple crossarm levels
- Retrofit of failed wood-pole crossarm mounting hardware
Installation sequence
- Position the crossarm horizontally at pole-top elevation per drawing.
- Align bracket plate with the crossarm’s center mounting hole.
- Through-bore the pole at 9/16 in (M16) or 11/16 in (M20) per bracket type.
- Insert through-bolt with a square washer on the back side; thread 2 nuts.
- Verify the crossarm is level both ways (front-to-back and side-to-side) before final torque.
- Torque to 80–100 ft-lb (M16) or 120–150 ft-lb (M20).
Buyer’s Guide: Crossarm Mounting Bracket
1. When Do You Need a Crossarm Mounting Bracket?
A crossarm mounting bracket is the steel plate that bolts the crossarm to the pole. It’s the primary structural connection in any pole-line construction — conductors hang from insulators bolted to the crossarm, and the entire conductor load transfers through this bracket into the pole. Match the bracket type to the crossarm load class: standard duty for distribution (11–24.9 kV), heavy duty for transmission (34.5–69 kV), double-arm for any dead-end position requiring two parallel crossarms.
The double-arm variant (RAX-CMB-D) is essentially two parallel standard plates with the appropriate spacing for a 14–18 inch crossarm separation. Pair it with a Double Arming Plate at the back of the crossarm pair for a complete dead-end mounting assembly. The standard ANSI C135.6 hole pattern matches our Power Pole Cross Arm and Rectangular Cross Arm products directly — no field drilling required.
2. How to Choose the Right Size
Pick by crossarm type and load class.
- RAX-CMB-S — standard 6 inch angle crossarms, distribution voltages
- RAX-CMB-H — heavy 6–10 inch arms, light transmission
- RAX-CMB-D — double-arm dead-end construction
For pole top configurations not covered above (square or polygonal steel poles, fiberglass arms), request a project-specific bracket quote. 5–7 day tooling, 200-piece minimum.
