Ask for power cable (5)

I believe the answer is:

plead

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'ask for' is the definition.
(thesaurus)

'power cable' is the wordplay.
'power' becomes 'p' (symbol in physics).
'cable' becomes 'lead' (I can't justify this - if you can you should believe this answer much more).
'p'+'lead'='PLEAD'

Can you help me to learn more?

(Other definitions for plead that I've seen before include "Respond to charge" , "State whether one is guilty or not" , "Implore, entreat" , "Supplicate" , "Argue (a position in court)" .)

I've seen this clue in The Irish Times.

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