A line-jumper apparatus typically includes a first connector, a second connector, and a housing attached to the first connector and the second connector. In a closed position, the housing provides a low-resistance current path and a high-resistance current path between the first connector and the second connector. In an open position, the housing inhibits current from flowing between the first connector and the second connector. The housing is configured so that, when the housing is transitioned from the closed position to the open position, the low-resistance current path is opened before the high-resistance current path. The housing typically includes a safety mechanism that prevents the low-resistance current path from being opened unless the high-resistance current path is closed.