Sent two letters in one short day (5)
I believe the answer is:
'sent two letters' is the definition.
The answer and definition can be both to do with communicating as well as being past participle verbs.
Maybe there's a link between them I don't understand?
'one short day' is the wordplay.
'one' becomes 'wire' (I can't explain this - if you can you should believe this answer much more).
'short day' becomes 'd' (abbreviation for day; 'short' indicates a short form).
'in' acts as a link.
Can you help me to learn more?
(Other definitions for wired that I've seen before include "having Internet connection" , "Equipped for electrical connection" , "Bugged" , "set up for broadcast?" , "Equipped for electricity" .)