Cut off, either stop or start flow of current? (4,3,4)
I believe the answer is:
pull the plug
'cut off' is the definition.
(to pull the plug is to stop or interrupt something)
'either stop or start flow of current?' is the wordplay.
I cannot quite understand how this works, but
'stop' could be 'plug' (plug is a kind of stop) and 'plug' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
(Other definitions for pull the plug that I've seen before include "Stop (something) continuing - empty the bath!" , "Scrap" .)