A sensor line, which is configured to detect an ambient variable and which extends from a first end to a second end in a longitudinal direction, has a line core and a number of mutually spaced resistance elements with a resistance value. The resistance value varies depending on a value of the ambient variables. A measuring assembly having the sensor line is also provided.

An intelligent leakage current detection and interruption device for a power cord, including a switch module configured to control electrical connection of first and second power lines between input and output ends; a leakage current detection module, including first and second leakage current detection lines coupled in series, configured to detect a leakage current on the first and second power lines, respectively; a detection monitoring module, coupled in series to the first and second leakage current detection lines and to the first and second power lines, configured to detect an open circuit condition in the first or second leakage current detection line; and a drive module, coupled to the switch module, the leakage current detection module and the detection monitoring module, configured to drive the switch module to cut off power to the output end in response to any detected leakage current or open circuit condition.

An insulated wire capable of changing color when overheated under a current load includes an insulated core, at least one thermochromic strip, and a transparent plastic protective layer. The thermochromic strip is wound and fixed on the peripheral surface of the insulated core. The transparent plastic protective layer clads the peripheral surface of the insulated core and/or the top surface of the thermochromic strip. When the insulated core is overloaded and generates heat, the heat is transmitted to, and thereby changes the color of, the thermochromic strip. The color change is visible through the transparent plastic protective layer and can therefore alert the wire user in real time that the load on the insulated wire should be lowered.

A sensor line for detecting an external influence on a cable is described. The sensor line comprises: a capacitor, a first dielectric, which has a first compressibility and a first permittivity, and a second dielectric, which has a second compressibility and a second permittivity. The first compressibility is smaller than the second compressibility. The first permittivity differs from the second permittivity. The sensor line is configured so that at least the second dielectric is compressible or extensible in the event of a movement of the sensor line, so that a total permittivity, which is composed of the first permittivity and the second permittivity, is variable in the movement of the sensor line. Due to the change in total permittivity, a change in the capacitance of the capacitor can be produced, which is detectable, in order to detect the external influence on the cable.

Systems and methods for tamper proof cables are described herein. In certain implementations, a system includes one or more pieces of equipment and one or more tamper proof cables connecting the equipment within a network. A tamper proof cable includes a core that provides a transmission medium through the cable; an insulator enveloping the core; a first conductive braid encircling the insulator; a dielectric enveloping the first conductive braid; and a second conductive braid encircling the dielectric, the first and second conductive braids, and the dielectric forming a capacitor. The system includes one or more detectors, each detector coupled to the tamper proof cables, each detector and an associated capacitor forming a tuned circuit, the detectors providing a signal when an associated portion of the tamper proof cables is tampered with; a monitor coupled to the detectors that notifies an infrastructure management system when the signal is received.

Disclosed herein are cable systems that include a cable defining a sensing path and comprising a working strand and one or more sensing strands, a signal source to impart a test signal between a first terminal and a second terminal, a sensor to detect the test signal, a transmitter to transmit the test signal to a receiver, and an indicator to generate a display indicative of the test signal. Certain preferred embodiments describe sensing strands that are arranged in alternating concentric layers and/or extend lengthwise in loops. Such configurations facilitate the detection of breakage, insults, excess tension, or excess bending in the cable. The sensing strands may include a fixed resistor to establish a known resistance and facilitate the detection of small resistive changes.

Disclosed herein are cable systems that include a cable defining a sensing path and comprising a working strand and one or more sensing strands, a signal source to impart a test signal between a first terminal and a second terminal, a sensor to detect the test signal, a transmitter to transmit the test signal to a receiver, and an indicator to generate a display indicative of the test signal. Certain preferred embodiments describe sensing strands that are arranged in alternating concentric layers and/or extend lengthwise in loops. Such configurations facilitate the detection of breakage, insults, excess tension, or excess bending in the cable. The sensing strands may include a fixed resistor to establish a known resistance and facilitate the detection of small resistive changes.

An electrical component including a polymeric body which (i) defines at least one electrical connection; or (ii) is configured for attachment to an electrical cable or wire; or (iii) is configured for attachment to an electrical apparatus, wherein the polymeric body or a portion thereof includes a thermochromic composition which has a first colour condition below a first threshold temperature and a second colour condition if the composition is heated above the first threshold temperature, and wherein the thermochromic composition maintains the second colour condition until it is cooled below a second threshold temperature.

A cable is provided for detecting tampering thereof. The cable has at least one copper signal cable, a binder, an inner jacket, an armor, and at least one optical fiber sensor element, disposed within the cable. The at least one optical fiber sensor element is configured attenuate under stress to the cable, sufficient to detect a breach or tapping of the copper signal cable therein.

A cable is provided for detecting tampering thereof. The cable has at least two copper signal cables, at least one hollow buffer tubes located abutting the two copper signal cables, an inner jacket, an armor, and at least one loose tube optical fiber sensor element disposed within the cable in a configuration that subjects the optical fiber sensor to external conditions. The at least one loose tube optical fiber sensor element is located between and abutting at least one of the copper signal cables and the at least one adjacent hollow buffer tube. The at least one loose tube optical fiber sensor element is configured attenuate under changes in the external conditions.