Tower over there's vacated after work on burst main (8)
I believe the answer is:
dominate
'tower over' is the definition.
(thesaurus)
'there's vacated after work on burst main' is the wordplay.
'vacated' suggests removing the centre.
'after' says to put letters next to each other.
'work' becomes 'do' ('do work' can be a synonym of 'work'**).
'on' means one lot of letters goes inside another.
'burst' indicates anagramming the letters.
'there' with its middle removed is 'te'.
'main' anagrammed gives 'mina'.
'do' put inside 'mina' is 'domina'.
'te' put after 'domina' is 'DOMINATE'.
(Other definitions for dominate that I've seen before include "Rule" , "Be lord over" , "Master" , "Admit one in order to be in control" , "corner" .)