A multi-core cable includes a heat detection line including a twisted pair wire composed of a pair of heat detecting wires being twisted together, each of which includes a first conductor and a first insulator covering a periphery of the first conductor, a plurality of electric wires spirally twisted around the heat detection line, each of which includes a second conductor and a second insulator covering a periphery of the second conductor, and a sheath covering the heat detection line and the plurality of electric wires together. A melting point of the first insulator is lower than a melting point of the second insulator. The second conductor has a shape in a cross-section perpendicular to a cable longitudinal direction in which a width along a circumferential direction is gradually increased from a radially inward portion to a radially outward portion.

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.

A thermal sensor wire. The thermal sensor wire may include a thermal sensing portion extending along a wire axis of the thermal sensor wire; and a carrier portion, the carrier portion extending along the wire axis, adjacent to the thermal sensing portion, the thermal sensing portion comprising a polymer positive temperature coefficient (PPTC) material or a negative temperature coefficient (NTC) material.

An underground layable power cable, in particular a submarine cable, having at least one phase conductor and at least one optical fiber conductor. The optical fiber conductor is integrated in the phase conductor. The optical fiber conductor may include at least one optical fiber. Further, the optical fiber may be surrounded by at least one protective layer, which may be formed from a plastic-gel combination. The gel may at least one of a silicone gel, a glass fiber material, or a carbon fiber material.

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, 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.

Disclosed are systems and methods for a self-monitoring conducting system that can respond to temperature, strain, and/or radiation changes via the use of optical fibers. The self-monitoring conducting system comprises a conducting component integrated with one or more optical fibers. The temperature, strain, and/or radiation changes can be sensed or detected via optical interrogation of the one or more optical fibers.

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.

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.