Cable Protector Load Ratings Explained: 5t, 20t, 40t

“Rated to 40 tonnes” sounds definitive. It is not — unless you know whether that figure refers to axle load or gross vehicle weight. Getting this wrong is how cable protectors get crushed.

Axle load vs. gross vehicle weight

This is the distinction that matters most:

• Gross vehicle weight (GVW) — the total weight of the vehicle and its load
• Axle load — the weight carried by a single axle, which is what actually presses on the protector

A 32-tonne semi does not put 32 tonnes on your cable protector. It spreads that across five axles, so the worst-case axle load is typically 8–11 tonnes — for a standard European 6×2 configuration, roughly 11.5 t on the drive axle under full load.

Matching rating to application

Channel count and size

Rating and channel geometry are linked. More channels in the same width means thinner walls between them, which lowers the load rating. If you need both a high rating and many cables, you need a wider protector — not a denser one.

Standard channels run roughly 30x30mm (signal cable) up to 90x90mm (welding cable or hose). Check the internal dimension, not the external.

Lift-up vs. drop-over

Drop-over protectors are the most common: cables are laid, the protector is placed over them. Fast, but the cable ends must be accessible at both ends during placement.

Lift-up models have a hinged lid. You lay the body, drop the cables in from above, and close the lid. Slower to install but far easier when cables are already terminated or the run is long.

Installation details that cause failures

• Do not pin one end only. Unpinned protectors walk under traffic. Use the moulded pin holes on both ends.
• Do not butt sections loosely. Gaps let a tyre edge catch the lip and flip the section.
• Check the approach angle. A steep ramp onto a short protector can bottom out a low-clearance vehicle. Longer sections have gentler ramps.
• Match the colour to the hazard — black/yellow is standard, but all-black blends into asphalt at dusk.