Relay secondary cable line selection device without shielding layer

The utility model provides a relay secondary cable shielding-layer-free line selection device. The relay secondary cable shielding-layer-free line selection device comprises a charge change measuring device, a pulse voltage source, an insulating handle and a metal detection clamping piece. A low-voltage alternating current is applied to the cable through the pulse voltage source, so that an electric field is formed around the cable, whether inductive charges are generated or not is detected through the metal detection clamping piece and the charge change measuring device, the design of an equivalent capacitor is adopted, and the device is small and exquisite in design and convenient to carry; the device utilizes the principle of a parallel capacitor, and is simple to use, high in efficiency and low in manufacturing cost; in the using process, the device can be started by only needing a very small voltage, so that the personal safety of operation and inspection personnel can be effectively ensured, and acciden