Andy repositioned second live wire (6)
I believe the answer is:
dynamo
'live wire' is the definition.
(I've seen this before)
'andy repositioned second' is the wordplay.
'repositioned' indicates an anagram.
'second' becomes 'mo' (both are short periods of time).
'andy' is an anagram of 'dyna'.
'dyna'+'mo'='DYNAMO'
(Other definitions for dynamo that I've seen before include "Energetic person (colloq.)" , "Producer of electrical energy" , "activist?" , "Generator of electricity on Monday" , "Source of electric current" .)