Electrical wiring is fairly common, most people know someone
who has seen some. At the most basic level, it is a conductor,
usually copper, surrounded by an insulator. The insulator can be
as simple as air* but is usually a plastic such as PVC or silicone.
The plastic insulator acts as a solid
barrier to allow wiring to be
clustered together as well as a barrier to corrosion and is usually
colored to aid identification. Should wires rub against parts of
their parent structure or other wires, over time they can abrade
to the point that the insulator is breached. This exposes the
conductor which can allow short-circuits, arcing, and mixing of
signals.
Industries such as aviation** have a strong safety culture and an
increasing amount of wiring to deal with. Many aircraft rely
entirely upon reliable electrical wiring to fly at all and passenger
cabins have multiple data and power cables feeding each seat. It
seems probable that Swissair 111 <link> was brought down by a
failure of the insulation in the entertainment system. Aviation is
outstanding at fixing flaws and implemented more robust
insulation widely. Electrical faults continue to occur, however,
and have been implicated in subsequent incidents.
High quality maintenance and inspection is a central feature of
aviation safety and other industries, however, spotting fail(ing)
insulation on wiring isn't easy. I found one patent <link> that
proposes a layer below the surface of a different color so that
wear might be spotted visually. The problem here is that wiring
makes extensive use of color codes and as such, there just aren't
any colors left that would stand out.
To solve this, we move beyond the normal color palate. By
incorporating a UV fluorescent layer below the outer insulation,
abrasion of cables would stand out and be easily identifiable.
There are a few useful scenarios. Firstly, electrical technicians
could wear a headlight with e.g. 365nm LEDs while visually
inspecting the aircraft, abrasions would jump out. A flexible UV-
fluorescent probe to insert into bunched wiring. A UV-vis bore
scope to inspect enclosed regions. The aircraft itself could have
UV LEDs built into wiring rich regions, e.g. the avionics bay. The
aircraft structure could use fluorescent undercoat on wiring
guides etc.
There, improve safety and justify increased component cost. The
manufacturers will love it.
* or fuel if you're a British fuel pump manufacturer and enjoy
messing with people.
** a fascinating 20th century industry that disappeared sometime
in the 1st half of 2020.