Yesterday those lightning charging cable (picture) in our company caught fire and broke an iPad Air. The iPad was connected to its power supply when suddenly a flame shot out of the cable near the lightning connector. Luckily, our colleague was able to unplug the iPad immediately as he was next to the device. Otherwise something else on his desk could have caught fire. The iPad Air will no longer charge and is probably broken.
It was a first gen Apple lightning charging cable that had 'bulges' next to the plug (you can see them on the unburned end in the picture) but no cracks or breaks. The bubbles seem to appear as a result of normal usage, causing a shift of the internal cable shield. This obviously lead to a short-circuit that caused the fire.
As a precaution, we now disconnect all charging iPads at night and have replaced any lightning cables with suspicious bulges.
[UPDATE:] Apple replaced the device today in the Munich Apple Store. Initially a replacement was refused due to 'wear and tear', but after we asked to speak to a manager, the seriousness of the problem was recognized and the iPad was replaced.