Electrical overload protector (4)
I believe the answer is:
fuse
'electrical overload protector' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for fuse that I've seen before include "Weld together through heat" , "circuit-breaker" , "'Blend, merge (4)'" , "Safeguard in electrical circuit" , "Integrate" .)