Electrical accessory (7)
I believe the answer is:
adaptor
'electrical accessory' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for adaptor that I've seen before include "Connector (O, not E)" , "Device for connecting multiple plugs (O, not E)" , "Kind of electric plug" , "Electrical convertor" , "Tap road (anag)" .)