空开

空开	kōng kāi	circuit breaker (abbr. for 空气开关)
空	kōng	empty / air / sky / in vain
空	kòng	to empty / vacant / unoccupied / space / leisure / free time
开	kāi	to open (transitive or intransitive) / (of ships, vehicles, troops etc) to start / to turn on; to put in operation; to operate; to run / to boil / to write out (a prescription, check, invoice etc) / (directional complement) away; off / carat (gold) / abbr. for Kelvin, 开尔文 / abbr. for 开本, book format