live wire
From Longman Dictionary of Contemporary EnglishRelated topics: Electrical, Electricitylive wirelive wire /ˌlaɪv ˈwaɪə $ -ˈwaɪr/ noun [countable] 1 informalENERGETIC someone who is very active and has a lot of energy2 TEEa wire that has electricity passing through itExamples from the Corpuslive wire• Yet a kind of current emanated from her, she was like a live wire.• Estes' forehead brushed the live wire.• This college has come to life and advanced considerably under the direction of its very live wire Rector Mr Jocelyn Stevens.