A bushing (11) is provided with a twist regulation portion (A1) to regulate twist of a power cord (10) for setting an expected disconnection portion (A3) for the power cord (10) to be disconnected due to twist of the power cord (10) in a tubular inner space (11a) of the bushing (11) by regulating twist of the power cord (10) by the twist regulation portion (A1), and a spark attenuation portion (A2) is provided at a portion in the tubular inner space (11a) of the bushing (11) nearer to a distal end thereof than the twist regulation portion (A1) to attenuate spark (S) occurred in the tubular inner space due to disconnection of the power cord (10) at the expected disconnection portion (A3).
