Apparatus: the shops Christian P. Koop

One night, just days before this past Christmas, I was frantically awakened by my daughters telling me of a car fire across the street in a neighbor’s driveway.

I quickly ran downstairs and into my garage, picked up a fire extinguisher, and ran out the front door, yelling to my daughters to call 911. As soon as I saw the fire, I instantly realized my fire extinguisher would be useless. The car was fully involved, with flames licking tree branches more than 25 feet above the car. I pounded on the neighbor’s door, who was home yet oblivious to the inferno in his driveway just mere feet from his garage door. A fire crew from nearby Station 14 arrived in its Rosenbauer pumper in about six or seven minutes and proceeded to put out the fire that totally destroyed the late model Lexus SUV. While the fire was being put out, we heard two loud and powerful explosions as the front tires blew up. Luckily, the fuel tank did not ignite because the fire was extinguished before it got to the fuel tank.

After the fire was put out, my neighbor asked me what I thought had caused the fire. I responded that in my experience of having seen quite a few vehicle fires, including many emergency response vehicles (ERVs), I have seen a large percentage caused by faults in the electrical circuit, and I suspected this was the culprit in this case.

Electrical Causes

Many electrical fires are started when resistance in a connection or terminal increases. As resistance increases, that connection point in the circuit gets hotter and hotter. It basically becomes a heater element, and eventually the plastic insulation material can no longer withstand the increased heat and begins to melt. At this point, many times the melting material ignites and starts a fire. Other times, the melting material can begin heating, eventually melting insulation material in other circuits, and if they are connected to power and are not circuit protected, like battery power circuits, they can short to ground and also ignite insulating material and start a fire. This is one of the reasons the National Fire Protection Association (NFPA) requires that wiring meet specific high-temperature standards for insulating materials. This helps cut down on these types of fires but will not eliminate them.

Not only can electrical fires be caused by hot, high-resistance connections, they can also be caused by electrical modules that overheat internally and ignite. I have seen this happen to many different types of modules, and those that are hot at all times and do not go through the battery switch or ignition switch circuit are particularly vulnerable. I refer to these types of potential sources of vehicle fires as the most insidious because you can park the rig and walk away and a fire can start in minutes or even many hours later. If these fires are not discovered immediately and put out, they can grow very quickly, and the end result is a total loss of the vehicle.

Most people would think that these types of fires are not preventable, but in reality there is much that can be done. It all starts with a thorough visual inspection. Look for wiring connections that appear to be distorted or discolored. If you see a potential issue, check the temperature of the connector or module. If it is much hotter than the rest of