Too much juice will melt them (5)
I believe the answer is:
fuses
'too much juice will melt them' is the definition.
I can't tell whether this definition defines the answer.
'will melt them' is the wordplay.
'will' says to put letters next to each other (I've seen this in other clues).
'melt' becomes 'fuse' (fusing is a kind of melting).
'them' becomes 's' (I can't justify this - if you can you should give a lot more credence to this answer).
'fuse' put next to 's' is 'FUSES'.
Can you help me to learn more?
(Other definitions for fuses that I've seen before include "Blends or amalgamates, say metals" , "Electrical safety devices" , "Welds together using heat" , "Blow one of these and lose your temper" , "They interrupt the electric current when they're overloaded" .)