In a path along which lines extend between an engine room and a trunk room, the distance between the line 34 and the line 36 is made smaller than the distance between the line 32 and the line 34. Further, the distance between the line 36 and the line 38 is made smaller than the distance between the line 32 and the line 38. Even if a conductive member damages the lines upon collision of a vehicle, the lines 34 and 38 transmitting signals for control of the relays are more likely to be short-circuited with the line 36 to attain a ground potential than to be short-circuited with the line 32 to attain a power supply potential +B. This can lower the probability that the system main relays, once controlled to an open state upon collision, become conductive again after the collision.