>We'd say "has a short fuse" and "take the biscuit" but maybe Terry has already told you that.

The primary meaning of "fuse" is electrical. The word we usually associate with whatever carries delayed flame to the explosive is "wick" (as in a candle or petroleum lamp), although there's a more specific expression in use among the specialists - and even I know it, but again it's not the most common one. So, when the kid in the nudist camp asked his mom why was that man so big, mom said "he ate a powder keg" - the kid, of course, started away shouting "he's gonna blow any moment now, his wick is short".