Introduction to Wires, Fuses, & Connectors
Wires
Fuses
Connectors
Wire
A car's wiring has to distribute power
from the battery
to devices located all over the car. It also has to transmit
data on a data bus, as well as a variety of digital and analog
signals from switches and sensors.
Bundles of wires under the steering column of
a car
| This
means that there are many different types of wires in your
car. Some wires that transmit signals from switches or sensors
carry almost no current. Those that provide power to large electric
motors carry lots of current.
If too much current goes through a wire, it can overheat
and melt. The amount of current that a wire can handle depends
on its length, composition, size and how it is bundled. Let's
take a quick look at how each of these properties affects the
wire's current-carrying capacity:
- Length - Each type of wire has a certain amount
of resistance per foot -- the longer the wire, the larger
the resistance. If the resistance is too high, a lot of the
power that flows down the wire will be wasted, the energy
lost as heat builds up in the wire. Ultimately, heat
build-up limits the current-carrying capacity of the wire,
as the temperature must not get hot enough to melt the
insulation.
- Composition - Automotive wire is usually composed
of fine copper strands. Generally, the finer the strands,
the lower the resistance and the more current the wire can
carry. The type of copper used has an effect on the
resistance of the wire, too.
- Wire gauge - The wire gauge, or size of the wire,
also determines how much resistance the wire has. The larger
the wire, the less resistance. The smaller the gauge, the
larger the wire -- so a 16-gauge wire is bigger than a
24-gauge wire. Wire gauges go all the way down to zero,
which is also called 1/0 (one aught). Even bigger than 1/0
is 00 (2/0, or two aught), and so on. The diameter of a 4/0
wire is almost half an inch (1.27 cm).
- Bundling - The way a wire is bundled affects how
well it can dissipate heat. If the wire is in a bundle with
50 other wires, it can carry a lot less current than if it
were the only wire in the bundle.
You can see how important it is to choose the correct wire
size. The job is made even more difficult by the number of
wires in a car, which continues to grow each year as new
features are added to even the most basic automobiles.
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Introduction to Wires, Fuses, & Connectors
Wires
Fuses
Connectors
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