Copper charges people helping barmen in Ireland (7)
I believe the answer is:
curates
'people helping barmen in ireland' is the definition.
(Irish term for an assistant to a spirit-grocer)
'copper charges' is the wordplay.
'copper' becomes 'cu' (chemical symbol).
'charges' becomes 'rates' (rate is a kind of charge).
'cu'+'rates'='CURATES'
(Other definitions for curates that I've seen before include "Members of the clergy" , "Servicemen" , "As ministry assistants" , "Clerics" , "clerical workers" .)