Abstract: A protector system is provided for use in a low voltage power feed arrangement including a device requiring a low voltage power feed, and a power source. The power source is capable of supplying the device with electrical power. The device is electrically connected to the power source by means of a power transmission line. A line protector set is electrically connected to the power transmission line between the device and the power source so that all power in the power transmission line must encounter the line protector before the power reaches the device. The line protector set comprises an over-voltage arrester and an over-current arrester. The over-voltage arrester is coupled in circuit for grounding the transmission line in the presence of an over-voltage condition. The over-current arrester comprises a positive temperature coefficient resistor electrically connected in series with the device for preventing over-currents on the transmission line from reaching the device.