How can electrical wires be protected from the hazards around them?
Electrical wires have a special rubber protective coating on them to protect from heat, cold, dirt, water, and antifreeze, as well as from each other. All wires are protected in a circuit with either a fuse or a relay. There are two main categories of automotive wire: PVC and cross-linked. The biggest difference between the two categories is temperature range, as shown below.
PVC wire is created by heating and then extruding through a die on the stranding. This insulation can be melted with a heat source, changing the form.
The three main types of PVC automotive wire are: 1. GPT – used for general circuit wiring and rated to 80 °C 2. TWP – lead-free, thin wall automotive wire rated to 105 °C 3. HDT – heavy wall automotive wiring rated to 80 °C
Cross-linked insulation is created by extruding polyethylene through a tube, under heat and pressure, in order to ‘cross-link’ or change the molecules of the insulation to another state. Cross-linked automotive wire can withstand much higher temperatures than PVC automotive wire.
As you can see, the differences between automotive wire insulation are mainly concerned about temperature rather than dirt or debris. The car manufacturer took all aspects of daily driving into consideration when building the vehicle you drive. The wiring that it has is already made to be protected not only with the coatings mentioned above, but also with wire looms, which are a plastic sheath over the wiring, and with electrical tape made to withstand the elements and keep the wiring in place so it doesn't move around. Wires rubbing through their insulation is the number one issue with electrical problems to date. This causes numerous crazy problems and could destroy a computer in your vehicle. All automotive wiring harnesses for vehicles to this day are all still made by hand, which is why they are so expensive if you have to replace an entire harness assembly.
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