When a used, new-to-you vehicle or machine arrives on the farm, it’s worth putting on your coveralls and giving it another more thorough inspection than it likely received at the auction sale or dealer’s lot when it was purchased. Doing exactly that saved this heavy truck from what would have been an inevitable fire. And if the truck had been parked inside the farm shop when that happened, the loss could have been devastating.
This Freightliner truck tractor was recently purchased from a rural garage that specializes in heavy truck and equipment repair. So we expected every modification and repair would have been made by one of the staff mechanics and be done to a reasonably competent standard.
A post-purchase inspection proved us wrong.
While rolling around underneath the truck on a creeper, we noticed that there were two heavy gauge cables running directly from the four heavy-duty batteries to a supplementary heater inside the cab. They were not protected by a fuse or circuit breaker.
What’s worse, they weren’t protected from fraying against the sharp edge of the hole drilled through the cab floor they were routed through. Nor were they securely fastened to the truck frame or other body components to keep them protected from snagging or other under-body risks.
When we noticed the problem, the cables were disconnected and removed in order to install a rubber grommet in the cab floor hole, encase them in a protective sheath and route them securely along a frame rail back to the batteries.
An inspection of the red, positive cable showed more than half of the thickness of the insulation had been worn away over time from rubbing on the sheet metal. There was less than a millimetre of insulation between the always-live electrical cable and the metal truck cab metal. If left unchecked, eventually the cable would have worn through to the bare wire, and that would result in arcing from the very high amperage available. The thick interior cab carpet just above it would have made an ideal starting point and combustible fuel for the initial fire.
The time spent in the shop doing the inspection that day on this truck certainly paid off.
Properly routing electrical lines
Here are some basic rules for properly routing electrical lines:
- Wires should never pass through a metal opening without a rubber grommet in place to prevent fraying.
- Wires should always be firmly attached to a frame or body component and never allowed to swing loosely.
- Running exterior wires exposed to the elements through a protective plastic sheath further helps keep them damage free.
- A fuse should always be installed to protect any aftermarket electrical components installed on a machine.