Did you ever wonder why some wires are bundled together in one aircraft wiring harness and others are not? Why does this wiring harness have 6 breakouts while this other harness has only two? Why didn’t the Lockheed Martin, Boeing, or InterConnect engineer just add those two wires to the larger harness? There are several reasons, but one important answer is crosstalk.
Crosstalk is a disturbance caused by the electric or magnetic fields of a nearby transmitted signal affecting a signal in an adjacent circuit. When a signal travels down a pair of wires in a wiring harness, the signal emerges from the other end, but the field that the signal creates around that pair can bleed over into adjacent wiring and creates crosstalk.
This effect can manifest itself as unstable, inaccurate or noisy signals. In turn these signals can cause erratic or incorrect instrument readings, erroneous input to aircraft control systems, poor audio or visual output and other similar undesirable results.
To reduce the crosstalk in a wiring harness, a twisted pair with shielded cable is frequently used. When an interfering signal is applied equally to both sides of the twisted pair, the interfering signal is neutralized. Another typical method used to reduce crosstalk is to physically separate signals of different types into separate harnesses, or separate branches of the same harness. Since crosstalk is very dependent on proximity, a small separation can yield a significant improvement in signal quality.
In this photo you can see aircraft wiring harnesses that InterConnect Wiring not only made, but designed as well. During design, InterConnect’s engineering team spent extensive time determining where to separate wires to prevent crosstalk, how to bundle them along the forward and aft fuselage, and where to place the clamps. In the picture, wires which are similar (such as a signal wires or power wires) are bundled together and clamped along three separate channels.
To hear more about InterConnect Wiring, and learn about InterConnect’s “WHY”, view this video.