Electrician's outright blunder (5)
I believe the answer is:
gaffe
'blunder' is the definition.
(I know that gaffe is a type of blunder)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for gaffe that I've seen before include "Clanger" , "Tactless comment" , "embarrassing mistake" , "slip" , "Brick (that's dropped)" .)