I think perhaps he means when the "lowest bidder" electrolytic capacitor in the AC/DC converter, with the 2000 hour specified life span (83 days)[1], overheats, bursts, and shorts the AC wiring inside your wall.

Presumably you installed it in a proper outlet box (I like steel) and it will be able to handle the energy released while waiting for the line's circuit breaker to trip without reaching the ignition point of anything inside the wall.

[1] Not that these people would use them, but you find them in a lot of gear. Especially dramatic when their tops are close enough to a case or heatsink to short when they burst.