Firecracker parts (5)
I believe the answer is:
fuses
'firecracker parts' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for fuses that I've seen before include "Blends together as with heat" , "Circuit breakers" , "They interrupt the electric current when they're overloaded" , "Blow one of these and lose your temper" , "Electrical safety devices" .)