Close call, note, making electrical equipment safe (4,5)
I believe the answer is:
near thing
'close call' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for near thing that I've seen before include "Narrow escape, missed by a small margin (4.5)" , "almost a disaster" , "Something that barely avoids failure or disaster" , "Narrow escape, close shave" , "Even the short-sighted could plainly see that" .)