Current in fuse applied to keep going (7,2)
I believe the answer is:
soldier on
'keep going' is the definition.
(I've seen this before)
'current in fuse applied' is the wordplay.
'current' becomes 'I' (physics symbol).
'in' indicates putting letters inside.
'fuse' becomes 'solder' (I've seen this in another clue).
'applied' becomes 'on'.
'i' put into 'solder' is 'soldier'.
'soldier'+'on'='SOLDIER ON'
'to' acts as a link.
(Other definitions for soldier on that I've seen before include "Persevere (colloq.)" , "... to bear up" , "Keep struggling" , "plug away" , "Persist in spite of difficulties" .)