Current source of master's trendy interior (5)
I believe the answer is:
mains
'current source' is the definition.
'mains' can be an answer for 'source' (I have seen 'source of power' mean 'mains' so perhaps 'source' could also mean 'mains'). I'm not certain of the 'current' bit.
'master's trendy interior' is the wordplay.
'master's' becomes 'MA's' (Master of Arts).
'trendy' becomes 'in' ('in' can mean fashionable).
'interior' indicates putting letters inside.
'mas' going around 'in' is 'MAINS'.
'of' is the link.
Can you help me to learn more?
(Other definitions for mains that I've seen before include "Utility network" , "Followers of those starting" , "power supply" , "Source of electricity or gas" , "Water, gas or electricity supply" .)