Ah, the art of making things 'squaddie-proof' ..
A few decades ago I was involved in designing some very sophisticated electronic gubbins which had to be used by all 3 services in all sorts of environments. One requirement was to have it light, small but rugged, but also to be able to be powered off internal rechargeable battery, 12v-28v DC, or 110-240v AC 50-60 Hz. We thought we'd provided obvious easy and idiot-proof external connectors and leads clearly labelled for all these options. All had been thoroughly tested from Arctic to very sandy, airborne to submarine. During one early and important operational deployment to somewhere rather inaccessible and uncomfortable, however, users reported that it had suddenly stopped working. We had to send out a team including from the designers to troubleshoot on the spot. It turned out that a squaddie had for some reason bodged a 240v AC power source into the DC input point and blown some important innards; he had not told anyone. We had failed to anticipate this possibility, which had not been in the military specification. We had to do a modification to ensure that if this happened again it would lead only to a cutout and warning, requiring a reset via a button, for which we had to find room (all the displays had to be readable in bright snow sunlight, and buttons individually pushable with a heavily gloved hand: RM requirement!). Obviously, it was our design team which was blamed for this oversight
(mere guide at) Jet Age Museum, Gloucestershire Airporthttp://www.jetagemuseum.org/
TripAdvisor Excellence Award 2015http://www.tripadvisor.co.uk/Attraction ... gland.html