Prysmian S.p.a.

Pirelli Cavi E Sistemi S.p.a.

Politecnico Di Milano

Luigi Caimi

Alberto Bareggi

Sergio Belli

Luca Balconi

Vito Scrima

Ivan Troia

Enrico Albizzati

Attilio Citterio

Antonio Zaopo

Claudio Bosisio

Enrico Maria Consonni

Giovanni Pozzati

Davide Ceschiat

Flavio Casiraghi

Vincenzo Crisci

Luigi De Martino

Massimo Gola

Stefano Pogliani

Armando Michele Ferrari

Romain Besson

Sergio Gutierrez

Pauline Audebet

Serge Colombier

Disclosed herein are flame-retardant electric cables () having a core containing an electric conductor () and an electrically insulating layer () made from a flame-retardant polyolefin-based composition including a) a cross-linked polyolefin as base polymer, b) silica, and c) carbon nanotubes, wherein the amount of silica is from 5 wt % to 10 wt % of the polyolefin-based composition, and the amount of carbon nanotubes is from 0.5 wt % to 2 wt % of the polyolefin-based composition. Such cables have improved flame retardant performances, especially regarding a lower occurrence of droplets during burning, which render them capable of being certified in higher classes of the current international standards, for example of the standard EN 50399:2011/A1 (2016).

Flame retardant electrical cable

A flame-retardant cable having a core is disclosed. The cable contains at least one conductor and a coating made from a low smoke zero halogen flame-retardant polymer composition. The polymer composition contains a halogen free base polymer added with a) less than 170 phr of at least one metal hydroxide; b) from 1 to 10 phr of a phyllosilicate clay; c) at least 1 phr and less than 10 phr of melamine or a derivative thereof; and d) an alkali or alkaline-earth metal carbonate. The cable has improved reaction to fire performances especially in that no dripping occurs during burning, which renders it compliant with the requirements of the more recent international standards.

Flame-retardant cable with self-extinguishing coating layer

Electrical field grading material which comprises a non-polar elastomeric polymer, a phyllosilicate filler and a carbon black filler, wherein any carbon black filler present in the electric field grading material has a dibutyl phthalate (DBP) absorption number from 30 to 80 ml/100 g. The above material may be used in electrical cable accessories, particularly electrical cable joints or terminations for medium or high voltage cable. The electrical field grading material according to the present invention has varioresistive properties, particularly a significant variation of electrical conductivity as a function of the applied voltage within a reduced voltage range, so as to guarantee a high value of conductivity above a critical value of the electrical field, and therefore to ensure an even distribution of the electrical field lines within the material.

Electrical field grading material and use thereof in electrical cable accessories

An electric cable for high-voltage applications is disclosed which comprises a core surrounded by an electrically insulating layer made of a composition based on a thermoplastic polymeric material charged with boron nitride powder in an amount up to 20 wt % with respect to the weight of the insulating composition, the boron nitride powder having a particle size distribution D50 up 0 to 15 &#x3bc;m. Such a cable has improved thermal conductivity property as well as good dielectric resistance and workability in particular through extrusion processes.

Electric cable with improved thermoplastic insulating layer

A method for manufacturing an electric cable joint is described. The method includes: a step of providing two electric cables, each cable containing an electric conductor and a thermoplastic insulation system surrounding the electric conductor and containing an inner and an outer thermoplastic semiconducting layers and a thermoplastic insulating layer; a step of joining the terminal portions of the electric conductors of the first and second electric cables to form an electric conductor joint; a step of surrounding the electric conductor joint with a joint inner layer of a thermoplastic semiconducting material having a dynamic storage modulus E'; a step of surrounding the joint inner layer with a joint insulating layer of a thermoplastic insulating material having a dynamic storage modulus E&#x2032;smaller than E&#x2032;; and a step of surrounding the joint insulating layer with a joint outer layer of a thermoplastic semiconducting material having a dynamic storage modulus E&#x2032;.

Joint for electric cables with thermoplastic insulation and method for manufacturing the same

Energy cable comprising, from the interior to the exterior, an electrical conductor, an inner semiconductive layer, an electrically insulating layer made from a thermoplastic material in admixture with a dielectric fluid, and an outer semiconductive layer, wherein the outer semiconductive layer comprises: (i) from 55 wt % to 90 wt % of a copolymer of ethylene with at least one ester comonomer having an ethylenic unsaturation; (ii) from 10 wt % to 45 wt % of a propylene copolymer with at least one olefin comonomer selected from ethylene and an &#x3b1;-olefin other than propylene, said copolymer having a melting point of from 145&#xb0; C. to 170&#xb0; C. and a melting enthalpy of from 40 J/g to 80 J/g; (iii) at least one conductive filler; (iv) at least one dielectric fluid; the amounts of (i) and (ii) being expressed with respect to the total weight of the polymeric components of the layer. The outer semiconductive layer is cold-strippable, having an adhesion with the underlying thermoplastic insulating layer which can be tuned so as to obtain a suitable balance between strippability at a temperature ranging from about 0&#xb0; C. to about 40&#xb0; C., without applying heat, and stable adhesion with the insulating layer during the cable lifespan.

Energy cable having a cold-strippable semiconductive layer

A fire resistant optical cable includes: a plurality of optical fibers; at least one tubular layer of a ceramifiable material surrounding the plurality of optical fibers; and at least one flame shielding layer surrounding the tubular layer. The tubular layer of the ceramifiable material is able to mechanically protect the optical fibers not only during heating but also when the fire is extinguished, since it forms a sufficiently robust layer to withstand the mechanical stresses caused by the collapsing of the materials still surrounding the cable, especially in the transition portions between hot and cold zones. The tubular layer of the ceramifiable material is protected by means of at least one flame shielding layer which prevents the flames from directly acting on the ceramifiable material.

Fire resistant optical cable

Cable, in particular for electric energy transportation or distribution, and an insulating composition used therein

The disclsoure describes an electric conductor having a coating layer with the property of strippability so that it can be stripped from the electric conductor, and a method for controlling the strippability of the coating layer from the electric conductor, with the electrical insulation properties of the cable coating being kept constant after exposure to moisture. The method involves adding to a polymeric composition forming the coating layer a predetermined amount of a polyolefinic compound, which contains at least one unsaturation and at least one carboxyl group in the polymer chain.

Cable with fire-resistant, moisture-resistant coating

The present invention relates to a coating for cables which is capable of protecting the cable against accidental impacts. By inserting into the structure of a power transmissioncable a suitable coating of expanded polymer material of adequate thickness, preferably in contact with the sheath of outer polymer coating, it is possible to obtain a cable which has a high impact strength. The Applicant has moreover observed that an expanded polymer material used as a coating for cables makes it possible to obtain a higher impact strength for this cable than using a similar coating based on the same polymer which is not expanded. A cable with a coating of this type has various advantages over a conventional cable with metal armor, such as, for example, easier processing, a reduction in the weight and dimensions of the finished cable and a lower environmental impact as regards recycling of the cable once its working cycle is over.

Cable with impact-resistant coating

A cable for electric power transmission, electric power distribution or telecommunications, having an inner layer including a self-repairing material. The self-repairing material has properties including a predetermined cohesiveness and a controlled flowability. In the event of a discontinuity in at least one of the cable coating layers, these properties assist in reestablishing the continuity of the cable coating layers.

Electrical cable with self-repairing protection

The invention relates to a coating for cable which is capable of protecting the cable against accidental impacts. By inserting into the structure of a power transmission cable a suitable coating of expanded polymer material of adequate thickness, preferably in contact with the sheath of outer polymer coating to obtain a cable which has a high impact strength.

Electrical cable, in particular for medium- or high-voltage power transmission or distribution, having a metal shield and a semiconductive water-blocking expanded layer. This layer exerts three main functions, the first one is to elastically and uniformly absorb radial forces of expansion and contraction of the cable coating layers due to thermal cycles of the cable during use, thus preventing deformations or breakages in the metal shield, the second one is to ensure electrical continuity between the cable core and the metal shield, the third one is to effectively avoid penetration and propagation of moisture and/or water along the cable core due, e.g., to possible ruptures in the metal shield. The third function is obtained by including in the expanded layer a water-swellable material.

Electrical cable having a semiconductive water-blocking expanded layer

The disclosure sets out a fire-retardant electrical cable including a metal conductor and at least a double layer polymer coating disposed to surround the metal conductor. The double layer coating defines an inner and an outer layer wherein the inner layer includes a polymer matrix, a predetermined first amount of a flame retardant inorganic filler and a predetermined amount of a coupling agent. The outer layer includes a polymer matrix and a predetermined second amount of a flame retardant inorganic filler. The inner layer employs the predetermined first amount of inorganic filler in an amount lower than the predetermined second amount of inorganic filler in the outer layer. The inner layer includes the predetermined amount of coupling agent in an amount such that upon placing the cable in water, it keeps the long term insulation resistance of the cable substantially constant.

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Lomagna, Italy

Luigi Caimi