An electrical cable (10) has at least one conductor (12), and further has a device for indicating the presence of an electrical voltage inside the cable (10). The device has at least one layer (14) at least partially covering the outer surface of the cable (10) in at least one region of the cable (10) and a means for transmitting a signal indicating the presence of an electrical voltage inside the cable (10).

A heat detection line includes a twisted pair wire composed of a pair of heat detecting wires being twisted together. Each heat detecting wire includes a conductor and an insulator covering a periphery of the conductor. The conductor is non-magnetic and composed of a copper alloy with a tensile strength of 900 MPa or more. A multi-core cable includes the heat detection line, a plurality of electric wires, and a sheath covering the heat detection line and the plurality of electric wires together. A melting point of the insulator of the heat detection line is lower than a melting point of an insulator of each of the plurality of electric wires.

An apparatus for indicating overstress in an electro-mechanical cable. The apparatus includes an overstress an overstress indicator cable including at least one non-twisted conductor disposed within a section of the electro-mechanical cable, where the non-twisted conductor is adapted to break when tension in the non-twisted conductor is greater than an allowable working load for the electro-mechanical cable.

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.

Provided is a system for directly sensing, measuring, or monitoring the temperature of an electrical conductor (31) of a power cable (10). A temperature sensitive capacitor (21C) is disposed in direct thermal contact with the electrical conductor (31). The temperature sensitive capacitor (21C) includes a dielectric material that has a dielectric constant variable with the temperature of the electrical conductor (31). The temperature of the electrical conductor (31) can be sensed, measured, or monitored by measuring the capacitance of the temperature sensitive capacitor (21C).

A thermochromic electrical device is made of thermochromic plastic material and has a visual indicator pre-printed with regular print or ink to allow visible warning of a scalding situation when the thermochromic plastic portion fades from its original color to leave the warning visible. The electric device may be any one of, for example, a cable tie, a cable connector, a terminal connector, a splice connector, and a cable jacket.

A cable includes a longitudinal structural element including at least one of an electrical conductor and an optical conductor, and a strain sensor arranged within a bending neutral region of the cable and mechanically coupled with the longitudinal structural element. The strain sensor includes an optical fiber coated with at least one coating layer, a release layer surrounding the coating layer, and a protective layer surrounding the release layer. The release layer includes a material selected from a silicone polymer, a fluoropolymer mixture or an extruded polymer containing a slip agent.

A cable includes a longitudinal structural element including at least one of an electrical conductor and an optical conductor, and a strain sensor arranged within a bending neutral region of the cable and mechanically coupled with the longitudinal structural element. The strain sensor includes an optical fiber coated with at least one coating layer, a release layer surrounding the coating layer, and a protective layer surrounding the release layer. The release layer includes a material selected from a silicone polymer, a fluoropolymer mixture or an extruded polymer containing a slip agent.

A method and apparatus for testing shield continuity are provided. In the method and apparatus, a transmitter transmits a first signal in common mode over a plurality of conductors of a cable or cabling installation having a shield. The first signal is transmitted in the common mode at a first end of the plurality of conductors. A receiver receives a plurality of second signals representative of the first signal at a second end of the plurality of conductors, respectively, and outputs data representative of the plurality of second signals. A processor receives the data representative of the plurality of second signals, determines a common mode insertion loss for the cable or cabling installation based on the plurality of second signals, determines, based on the common mode insertion loss, whether the shield is continuous or discontinuous and outputs data representative of whether the shield is continuous or discontinuous.