noun
lightning surge
Technical term in electrical engineering for a transient overvoltage caused by a lightning strike.
雷サージから電子機器を守るために、サージプロテクタを使う。
Use a surge protector to protect electronic devices from lightning surges.
サージ alone means 'surge' in general (electrical, pressure, etc.), while 雷サージ specifically refers to a surge caused by lightning.
Compound of 雷 (kaminari, 'lightning') and サージ (sāji, from English 'surge').