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.-- bs0u0155, Apr 29 2020 Swissair 111 https://en.wikipedi..._111#Probable_cause [bs0u0155, Apr 29 2020] Color abrasion indicator https://patents.justia.com/patent/6207902 [bs0u0155, Apr 29 2020] Oh dear, this is an actual really good idea. Feels like it doesn't belong here. [+]-- wagster, Apr 29 2020 I think a prototype would be trivial to make too.-- bs0u0155, Apr 29 2020 random, halfbakery