Charged boundary intended to keep cattle in (8,5)
I believe the answer is:
electric fence
'intended to keep cattle in' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'charged boundary' is the wordplay.
'charged' becomes 'electric' (synonyms).
'boundary' becomes 'fence' (I am not sure about this - if you are sure you should believe this answer much more).
'electric'+'fence'='ELECTRIC FENCE'
Can you help me to learn more?
(Other definitions for electric fence that I've seen before include "Shocking barrier" , "Wire keeping animals in a field" , "Feel eccentric (anag.)" , "Way of stopping animals straying" , "What stops farm animals straying" .)