On-cable pressure barrier device, manufacturing process for manufacturing said device and MOTO-compressor line comprising said device

Abstract

On-cable pressure barrier device (6) fitted on a cable comprising an insulating sheath (3 d) around a plurality of wires (3 e) individually insulated, a part of said cable within the on-cable pressure barrier device is stripped of all insulation in order to expose the conducting core (6d1,6d2) of each wire -(6c1,6c2) of the plurality of wires, the on-cable pressure barrier device (6) comprising a resin part (6f) extending over, a first part (6d1) of the exposed conducting core of each wire connected to a first part (3c1) of the cable through a first part (6d1) of said wire, a second part (6d2) of the exposed conducting core of each wire connected to a second part (3c2) of the cable through a second part (6c2) of said wire extends outside said resin part (6f), the exposed conducting core of each wire and the resin part (6f) being able to stop the diffusion of gas incoming from the first part of the cable.

Description

[0001] DESCRIPTION

[0002] TITLE: ON-CABLE PRESSURE BARRIER DEVICE, MANUFACTURING PROCESS FOR MANUFACTURING SAID DEVICE AND MOTO-COMPRESSOR LINE COMPRISING SAID

[0003] DEVICE

[0004] Field of the invention:

[0005] The present invention relates to seal barrier for cable connection, in particular for cable connection in pressurized environments.

[0006] State of the Art:

[0007] A moto-compressor contains a compressor and a turbine in a single air-tight enclosure reducing the risk of leaks. In some embodiments, the moto-compressor also compri ses a magnetic bearing or an AMB (acronym for “active magnetic bearing”).

[0008] Such a moto-compressor is commonly used for pressurizing explosible substances like natural gas or hazardous gas like carbon dioxide. In such applications, the moto-compressor operates with an internal pressure much higher than the atmospheric pressure. Due to the hazardous gas involved, such a moto-compressor is generally placed in a limited access area, like an ATEX or HAZLOC zone. ATEX stands for “Atmosphere Explosible” in French and refers to a European directive on hazardous and explosible atmospheres. It is the European equivalent to HAZLOC US standard. HAZLOC stands for “HAZardous LOCation” and is a US standard on hazardous and explosible atmospheres.

[0009] The control cabinets used for controlling such a moto- compressor are not located in a limited access area like the moto- compressor, but in a safe area according to the ATEX directive.

[0010] Figure [Fig 1 ] illustrates a moto-compressor ICL (acronym for “moto-compressor line”) comprising a medium voltage junction box 1 connecting a control cabinet 2 to the moto-compressor 3. A first cable 2c connects the control cabinet 2 to the medium voltage junction box 1 and a second cable 3 c connects the medium voltage junction box 1 to the moto-compressor 3.

[0011] Both the medium voltage junction box 1 and the moto- compressor 3 are located in an ATEX area, while the control cabinet 2 resides in a safe area as outlined by reference 5.

[0012] Each cable 2c, 3 c comprises an insulating sheath 2d, 3 d and a plurality 2e,3 e of at least two wires. Each cable 2c, 3 c is ATEX rated.

[0013] Such cables 2c, 3 c are connected to the medium voltage junction box 1 and to the control cabinet 2 through cable glands 2a, 2f, 3f.

[0014] The control cabinet 2 is connected to the moto-compressor 3 through an ATEX rated connector 3 a, 3b . The ATEX rated connector provides a first pressure barrier to gas diffusion through the electrical connection.

[0015] However, a failure or the connector 3 a, 3b, total or partial, could lead to a gas leak in the second cable 3 c. The gas could then diffuse along the cable 3b to the medium voltage junction box 1. The insulating sheath 3 d would then behave like a hose, piping the gas from the connector 3 a, 3b to medium voltage junction box.

[0016] In such an occurrence, there is a risk of gas buildup in the medium voltage junction box 1 , and of a secondary gas diffusion along the first cable 2c to the control cabinet 2 in the safe zone.

[0017] Arrows designated first and secondary gas diffusions.

[0018] Such a secondary diffusion would defeat the ATEX / HAZLOC zoning and be a source of danger for the personnel and facility housing the moto-compressor.

[0019] In order to mitigate such a potential failure, both the gas buildup in the medium voltage junction box and secondary diffusion through the first cable 2c have to be prevented.

[0020] A hood 4b and a gas detector 4c are commonly installed. In the event of a gas diffusion through the second cable 3 c, the gas accumulating within the medium voltage junction box 1 i s vented through breather valve 4a, and guided to the gas detector 4c by the hood 4b . As soon as the gas is detected, a signal is emitted, linked to an alarm and / or a contingency plan. Such a contingency plan can include shutting down the moto-compressor 3 or informing on premise personnel of the incident.

[0021] It can be appreciated that triggering such an alarm or a contingency plan does slow down or hinder the operation of the installation comprising the moto-compressor.

[0022] There i s a need of a moto-compressor able to mitigate any gas diffusion risk while maximizing its operational time.

[0023] Documents GB 1 188286, DE2209629 and DE2440826 are known.

[0024] Document GB 1 188286 di scloses a method for forming a gas seal in an electric cable. The insulating sheath is removed and a porous material is added instead of the insulating sheath, allowing for gas to diffuse out of the cable.

[0025] However, the method described does not disclose how to prevent the gas to further diffuse in the cable past the gas seal .

[0026] Document DE2209629 and document DE2440826 disclose methods to seal a cable after division. This document deals with restoring the sheathing integrity but is silent on the diffusion of gases and a potential barrier to said diffusion.

[0027] The technical problem is not solved by those documents.

[0028] Summary :

[0029] An obj ect of the invention is an on-cable pressure barrier device fitted on a cable comprising an insulating sheath around a plurality of wires individually insulated. The cable within the on-cable pressure barrier device is stripped of all insulation in order to expose a conducting core of each wire of the plurality of wires, the on-cable pressure barrier device comprising a resin part extending over a first part of the exposed conducting core of each wire connected to a first part of the cable, a second part of the exposed conducting core of each wire connected to a second part of the cable extends outside said resin part, the exposed conducting core of each wire and the resin part being able to stop the diffusion of gas incoming from the second part of the cable. The on-cable pressure barrier device can comprise an enclosure fitted with a breather valve, the breather valve communicating with the inside of said enclosure comprising atmospheric air.

[0030] A comb can be installed and removably fixed to the enclosure in order to keep the wires separated.

[0031] The plurality of wires can compri se at least two wires of at least two different gauges or diameter.

[0032] A comb can be installed and removably fixed to the enclosure in order to keep the wires separated, said comb being able to accommodate different wire gauges thanks to spacing of different sizes between teeth of the comb .

[0033] The comb can be placed on the exposed conducting core of the wires.

[0034] Two comb s can be provided, each comb being installed on one side of the exposed conducting core of the wires.

[0035] The enclosure can comprise three parts, a first part corresponding to half of the enclosure, extending from the first part of the cable to the second part of the cable, the other half of the enclosure being split in a second part and a third part, the second part extending to the second part of the cable, the third part extending to the first part of the cable.

[0036] Another obj ect of the invention is a moto-compressor line compri sing an on-cable pressure barrier device as described above, wherein the moto-compressor line compri ses a medium voltage junction box connected to a control cabinet by a first cable and to a moto- compressor by a second cable, each cable comprising an insulating sheath around at least two wires individually insulated, the medium voltage junction box, the moto-compressor and the second cable being located in an hazardous or explosible atmosphere, the control cabinet and the first cable being located in a safe atmosphere, the on-cable pressure barrier device being installed on the second cable in order to mitigate a gas diffusion from the moto-compressor to the control cabinet through the medium voltage junction box. Another obj ect of the invention is a manufacturing process of an on-cable pressure barrier device as described above, comprising the following steps: a. determining a suitable location for the on-cable pressure barrier device on the cable b . at the determined location, removing the insulating sheath of the cable without cutting the wires comprised therein. c. for each wire exposed by the removal of the insulating sheath of the cable, removing a portion of the wire insulating sheath so that the conducting core is exposed, d. inserting the cable through gaskets, provided on opposite faces of the enclosure first part, the cable residing inside each gasket so that the cable between said two gaskets is free of its insulating sheath, e. installing a second part of enclosure in order to form a hermetical seal with the first part of enclosure. f. pouring a curable resin in the enclosure so that a first part of the exposed conducting core of each wire is enclosed in resin along with each wire between said first exposed conducting core part and the first gasket, said first gasket being in contact with the cable extending from the on-cable pressure barrier device to the medium voltage junction box, g. curing the resin.

[0037] Yet another obj ect of the invention is a manufacturing process of an on-cable pressure barrier device as described above comprising a three-parts enclosure, comprising the following steps : a. determining a suitable location for the on-cable pressure barrier device on the cable, b . at the determined location, removing the insulating sheath of the cable without cutting the wires comprised therein, c. for each wire exposed by the removal of the insulating sheath of the cable, removing a portion of the wire insulating sheath so that the conducting core is exposed, d. inserting the cable through gaskets provided on opposite faces of the enclosure first part, the cable residing inside each gasket so that the cable between said two gaskets i s free of its insulating sheath, e. installing a second part of enclosure so that a hermetical seal is achieved with first part of enclosure, f. pouring a curable resin in the enclosure so that that a first part of the exposed conducting core of each wire is enclosed in resin along with each wire between said first exposed conducting core part and the first gasket, said first gasket being in contact with the cable extending from the on-cable pressure barrier device to the medium voltage junction box, g. curing the resin then installing a third part of enclosure so that a hermetical seal is achieved with both the first part of enclosure and the second part of enclosure.

[0038] Brief description of the drawings:

[0039] The present invention will be better understood from studying the detailed description of a number of embodiments considered by way of entirely non-limiting examples and illustrated by the attached drawing in which:

[0040] [Fig 1 ] shows a moto-compressor compri sing a medium voltage junction box with a breather valve and a detector,

[0041] [Fig 2] shows a moto-compressor comprising an on-cable pressure barrier device according to the invention,

[0042] [Fig 3 ] shows the main components of an on-cable pressure barrier device,

[0043] [Fig 4] shows the main components of an on-cable pressure barrier device comprising a comb and

[0044] [Fig 5] shows the main parts of an on-cable pressure barrier device enclosure.

[0045] Detailed description:

[0046] Figure [Fig 2] illustrates a moto-compressor according to the invention. The elements in common with the control system illustrated by figure [Fig 1 ] bear the same references.

[0047] The moto-compressor comprises a medium voltage junction box 1 connecting a control cabinet 2 to the moto-compressor 3. A first cable 2c connects the control cabinet 2 to the medium voltage junction box 1 and a second cable 3cl,3c2 connects the medium voltage junction box 1 to the moto-compressor 3. First cable 2c and second cable 3cl,3c2 are connected together through a connecting plate la comprised within the medium voltage junction box 1.

[0048] Both the medium voltage junction box 1 and the moto- compressor 3 are in an ATEX area, while the control cabinet 2 is in a safe area as outlined by reference 5.

[0049] Each cable 2c,3cl,3c2 comprises an insulating sheath 2d, 3d and a plurality 2e,3e of wires. Each cable is ATEX rated.

[0050] The medium voltage junction box comprises a first cable gland 2f through which the first cable 2c is connected to the command cabinet 2. The command cabinet 2 comprises its own cable gland 2a through which the first cable 2c is connected.

[0051] The medium voltage junction box comprises a second cable gland 3f through which the second cable 3cl,3c2 is connected.

[0052] The control cabinet 2 is connected to the moto-compressor 3 through an ATEX rated connector 3a, 3b.

[0053] In a similar fashion to the risk of gas diffusion described in regard to the control system illustrated by figure [Fig 1], a risk of gas diffusion through the second cable 3cl,3c2 from the moto-compressor 3 to the medium voltage junction box 1 exists, even as ATEX rated cables 2c,3cl,3c2 and ATEX rated connectors 3a, 3b are used.

[0054] In order to avoid such a gas diffusion and any consequences (gas buildup in medium voltage junction box 1 or further diffusion through first cable 2c), an on-cable pressure barrier device 6 is provided on the second cable 3cl,3c2. More precisely, a first part 3cl of the second cable connects the medium voltage junction box 1 to the on-cable pressure barrier device 6. A second part 3c2 of the second cable connects the cable pressure barrier device 6 to the moto-compressor 3. Despite two parts 3cl,3c2 being recited, the second cable 3cl,3c2 is not interrupted during the installation of the on-cable pressure barrier device 6 as it will be readily apparent in the present description. Figure [Fig 3] illustrates the main components of an on-cable pressure barrier device 6 according to the invention. The on-cable pressure barrier device 6 is particularly advantageous due to the fact its installation does not require the supporting cable 3cl,3c2 to be interrupted (i.e. the wires comprised in the second cable 3cl,3c2 are kept intact during installation).

[0055] The on-cable pressure barrier device 6 comprises an enclosure 6a, a breather valve 6b, two gaskets 6g, 6h, and a resin part 6f.

[0056] The enclosure 6a is designed so that it can be opened into at least two parts in order to be placed on the second cable 3cl,3c2.

[0057] The second cable 3cl,3c2 is secured in the enclosure 6a thanks to the gaskets 6g, 6h, enabling at the same time the enclosure 6a to be gas tight.

[0058] The second cable 3cl,3c2 comprised within the enclosure 6a is stripped of its insulating sheath 3d. Consequently, the at least one wire 6cl,6c2 comprised in the plurality 3e of wires within the second cable 3cl,3c2 is loose within the enclosure 6a.

[0059] In order for the on-cable pressure barrier device 6 to acquire its barrier properties, each wire 6cl,6c2 is stripped of a part of its own insulating sheath so that its conducting core 6dl,6d2 is exposed. Within the on-cable pressure barrier device 6, each wire comprises a first part 6cl with its insulating sheath, a first exposed conducting core part 6dl, a second exposed conducting core part 6d2 and a second part 6c2 with its insulating sheath. Despite two parts 6cl,6c2 for each wire being recited, the wires 6cl,6c2 and its exposed conducting core 6dl,6d2 are not interrupted during the installation of the on-cable pressure barrier device 6 as it will be readily apparent in the present description

[0060] A resin part 6f is then formed in the enclosure 6a so that it covers a first part 6dl of the exposed conducting core of each wire 6cl,6c2 along with a first part 6cl of each wire up to the first gasket 6g through which a first part 3cl of the second cable is passing through. The resin part 6f extends in the other directions up to the enclosure 6a.

[0061] The remaining part of the enclosure is kept free of any resin and comprises a second part 6d2 of the exposed conducting core of each wire along with a second part 6c2 of each wire up to the second gasket 6h through which a second part 3 c2 of the second cable i s passing through.

[0062] In the case of a gas diffusion within the insulating sheath 3 d of the second part 3 c2 of the second cable, the gas is released within the enclosure 6a through the second part 6d2 of the exposed conducting core of each wire extending outside of the resin part 6f.

[0063] However, due to the mating contact between the resin part 6f, the first part 6d l of each exposed conducting core and the first part 6c l of each wire, the gas diffusion cannot propagate further, in particular along the first part 3 c l of the second cable and the first part 6d l of each wire. The gas i s then vented through the breather valve 6b .

[0064] It is therefore understood that the inner volume of said enclosure 6a comprises either atmospheric air, at least a gas, in case of gas leakage inside the box or a mixture of atmospheric air and at least a gas. Said atmospheric air, at least a gas or mixture of atmospheric air and at least a gas inside the enclosure, have a pressure corresponding, comparable, or around atmospheric air pressure. In a preferred embodiment said atmospheric air, at least a gas or mixture of atmospheric air and at least a gas, inside the enclosure, have a pressure equal to atmospheric air pressure. It is an obj ect of the present invention to provide an inner volume of said enclosure unpressurized with respect to external air atmosphere, thanks to the breather valve 6b .

[0065] In order to fully understand the operation of the on-cable pressure barrier device 6, one need to be reminded the basic laws of diffusion.

[0066] Gas diffusion happens when a difference of pressure exists between two areas that are connected. In the present application, the moto-compressor 3 i s comprised within a casing wherein a gas is under pressure. The moto-compressor 3 has to be powered and controlled which implies the presence of at least a cable 3 c l ,3 c2. The cable 3 c l ,3 c2 is connected through an ATEX rated connector as previously stated. This connector is designed so that it forms a first pressure barrier against gas diffusion. However, in some occurrences, that first pressure barrier can fail, and gas can still diffuse through both the second cable sheath 3 d and each individual wire 6c l ,6c2 insulation sheath, both then acting as ducts. Upon reaching the on-cable pressure barrier device 6, the second cable sheath 3 d i s interrupted at the second gasket 6h. Any gas diffusing through the second cable sheath 3 d then either diffuses in the atmosphere around the gasket or within the on-cable pressure barrier device enclosure 6a.

[0067] In a similar manner, upon reaching the on-cable pressure barrier device 6, each wire insulating sheath is interrupted at the exposed core part 6d l ,6d2.

[0068] Any gas diffusing through a wire insulating sheath then diffuses within the on-cable pressure barrier device enclosure 6a.

[0069] In both cases, any gas that diffuses within the on-cable pressure barrier device enclosure 6a is then vented in the ATEX atmosphere through the breather valve 6b . The breather valve 6b is used to keep the pressure inside the enclosure 6a at an atmospheric level . It results from this venting that gas buildup in the enclosure 6a is prevented. Finally, due to the mating between the resin part 6f, the first part 6d l of the exposed conducting core of each wire and the enclosure 6a, there is no path for further gas diffusion. The pressure i s also kept low thanks to the breather valve 6b, further preventing gas diffusion.

[0070] It becomes apparent that the on-cable pressure barrier device 6 can be considered as a second pressure barrier against gas diffusion originating from the moto-compressor 3.

[0071] In some embodiments, there i s a risk of short-circuit or arcing between the wires 6c l ,6c2 after exposing their conducting cores 6d l ,6d2. In order to keep the exposed conducting cores 6d l ,6d2 separated, comb 6e is then installed and removably fixed to the enclosure 6a, as illustrated by figure [Fig 4] , The comb 6e is obviously manufactured out of a non-conducting material . An additional advantage of the comb 6e is to ease setting the resin part 6f, by giving a visual indication of the quantity of resin to pour in, in particular when the comb 6e is placed on the exposed conducting core 6d l ,6d2 of the wires. When the comb 6e is used as such a visual indicator, it sits between the first part 6d l and the second part 6d2 of the exposed conducting core of each wire 6c l ,6c2. It is to be noted that the comb 6e can be removed before a curable resin is poured and cured. After curing the resin, the comb is embedded within the resin part 6f and cannot be removed anymore.

[0072] In other embodiments, the comb 6e can be placed further away from the exposed conducting core 6d l ,6d2 of the wires, on wires 3c l ,3 c2 still comprising their insulating sheaths, as long as the exposed conducting core parts 6d l ,6d2 are kept at an appropriate di stance from each another in order to mitigate short-circuit and arcing risks. In yet other embodiments, two combs can be provided, either on the exposed conducting core parts 6d l ,6d2 of the wires or one on each side of the exposed core parts 6d l ,6d2 of the wires.

[0073] In some further embodiments, the wires 6c l ,6c2 are of at least two different gauges or diameter. The at least one comb 6e is able to accommodate the different wire gauges thanks to different spacing between teeth, forming openings of different size.

[0074] It is to be stressed that the continuity of the second cable 3 c l ,3 c2 is not altered by installing the on-cable pressure barrier device 6. The first part 3 c l and the second part 3 c2 of the second cable are merely meant to label the parts of the second cable one side and the other of the on-cable pressure barrier device 6.

[0075] Manufacturing process of an on-cable pressure barrier device will now be described. The manufacturing process comprises the following steps.

[0076] During a first step, the location of the on-cable pressure barrier device 6 is determined on the second cable 3 c l ,3 c2 connecting the medium voltage j unction box 1 to the moto-compressor 3.

[0077] At the determined location, the insulating sheath 3 d of the second cable 3 c l ,3 c2 is removed on a cable length equal to the length of the enclosure 6a of the on-cable pressure barrier. The insulating sheath 3 d i s removed without cutting the wires 6c l ,6c2 comprised therein. Each individual wire 6c l ,6c2 comprised in the second cable 3c l ,3 c2 are then unbundled and spread out. A limited portion of each wire 6c l ,6c2 is stripped of its insulating sheath so that the conducting core 6d l ,6d2 is exposed.

[0078] During a second step, the second cable 3 c l ,3 c2 is inserted through gaskets 6g, 6h in a manner that allows the gaskets 6g, 6h to be set each in a place where the insulation sheath 3 d ends after removal of a part during the first step of the manufacturing process. The second gasket 6h is located on the moto-compressor 3 side, the first gasket 6g being located on the medium voltage j unction box side.

[0079] The gaskets 6g, 6h are provided in a first part of the enclosure 6a.

[0080] A second part of enclosure 6a i s then sealed with the enclosure 6a first part.

[0081] A curable resin, in particular PU (acronym for “Polyurethane”) is poured in the enclosure to fill the enclosure so that a first exposed conducting core part 6d l of each wire 3 c l ,3 c2 is partly enclosed in resin along with a first part 3 c l of each wire part between said first exposed conducting core part 6d l and the first gasket 6g.

[0082] In a particular embodiment, at least a comb 6e is removably fixed to the enclosure prior to pouring the curable resin.

[0083] The resin can be either a UV curable resin or a thermally curable resin, the latter being preferred since heat can be applied through the enclosure. It is to be understood, that once the resin i s cured, the at least a comb 6e i s no longer removable.

[0084] The enclosure 6a has been described as comprising at least two parts. However, a three-parts enclosure is preferred. Figure [Fig 5 ] illustrates an enclosure 6a in three parts.

[0085] A first part 6a l corresponds to half the enclosure 6a, extending from the first gasket 6g to the second gasket 6h.

[0086] The other half enclosure is split into a second part 6a2 and a third part 6a3 .

[0087] During the manufacturing process, the second part 6a2 is set prior to pouring the curable resin. First part 6al and second part 6a2 then form a container wherein the curable resin can be poured from the opening corresponding to the place of the third part 6a3. In an embodiment, the second half of the enclosure is spread between the second part 6a2 and the third part 6a3 in order for the second part to cover at least all the resin part 6f. This is advantageous because it reduces the risks the curable resin flows outside of the enclosure 6a as it is poured in.

[0088] Once the resin is cured, the third part 6a3 of the enclosure 6a is sealed with the first part 6a l and second part 6a2.

[0089] It is to be appreciated that figures [Fig 3 ], [Fig 4] and [Fig 5] show the breather valve 6b on the same side the second gasket 6h is installed on. However, the breather valve 6b is advantageously installed so that it is located in the part of the enclosure where any gas buildup is susceptible to happen.

[0090] If the density of the gas considered is higher than the density of the atmosphere surrounding the on-cable pressure barrier device 6, it is more interesting to locate the breather valve 6b in the top most part of the enclosure 6a.

[0091] If the density of the gas considered is lower than the density of the atmosphere surrounding the on-cable pressure barrier device 6, it is more interesting to locate the breather valve 6b in the bottom most part of the enclosure 6a.

[0092] The on-cable pressure barrier device has been described in relationship with a moto-compressor in a moto-compressor line. However, it is readily apparent that the on-cable pressure barrier can be used on any cable connected to a pressurized environment, which could be subj ect to gas migration.

[0093] The moto-compressor line and the on-cable pressure barrier device allow a mitigation of gas diffusion in the occurrence of leak in the ATEX connector to the moto-compressor. Reference list:

[0094] 1 : medium voltage junction box la: connecting plate

[0095] 2: control cabinet

[0096] 2a: control cabinet cable gland

[0097] 2c: first cable

[0098] 2d: first cable insulating sheath

[0099] 2e: plurality of at least two wires within the first cable

[0100] 2f: first cable gland

[0101] 3: moto-compressor

[0102] 3a, 3b: ATEX connector

[0103] 3c,3cl,3c2: second cable

[0104] 3d: second cable insulating sheath

[0105] 3e: plurality of at least two wires within the second cable

[0106] 3f: second cable gland

[0107] 4a: breather valve

[0108] 4b: hood

[0109] 4c: gas detector

[0110] 5: limit between ATEX zone and Safe zone

[0111] 6: on-cable pressure barrier device

[0112] 6a: enclosure

[0113] 6al: enclosure first part

[0114] 6a2: enclosure second part

[0115] 6a3: enclosure third part

[0116] 6b: breather valve of the on-cable pressure barrier device 6c,6cl,6c2: wire comprised in the second cable plurality of wires 6d,6dl,6d2: conducting core of a wire

[0117] 6e: comb

[0118] 6f: resin part

[0119] 6g: first gasket

[0120] 6h: second gasket

Claims

CLAIMS1. On-cable pressure barrier device (6) destined to be fitted on a cable (3 c l ,3 c2) comprising an insulating sheath (3 d) around a plurality of wires (3 e) individually insulated, characterized by the fact the cable (3 c l ,3 c2) within the on-cable pressure barrier device (6) is stripped of all insulation in order to expose a conducting core (6d l ,6d2) of each wire (6c l ,6c2) of the plurality of wires, the on-cable pressure barrier device (6) comprising a resin part (6f) extending over a first part (6d 1 ) of the exposed conducting core of each wire connected to a first part (3 c l ) of the cable through a first part (6d 1 ) of said wire, a second part (6d2) of the exposed conducting core of each wire connected to a second part (3 c2) of the cable through a second part (6c2) of said wire extends outside said resin part (6f), the exposed conducting core of each wire and the resin part (6f) preventing the diffusion of gas incoming from the second part (3 c2) of the cable.

2. On-cable pressure barrier device according to claim 1 , wherein the on-cable pressure barrier device (6) comprises an enclosure (6a) fitted with a breather valve (6b), the breather valve (6b) communicating with an inner volume of said enclosure (6a) comprising atmospheric air, the enclosure (6a) comprising the exposed conducting core of the wire, the first part (6d l ) of said wire, the second part (6c2) of said wire and the resin part (6f).

3. On-cable pressure barrier device according to claim 2, wherein a comb (6e) is removably fixed to the enclosure (6a) in order to keep the wires separated.

4. On-cable pressure barrier device according to claim 1 , wherein the plurality of wires comprises at least two wires of at least two different gauges or diameter.

5. On-cable pressure barrier device according to claim 4, wherein the on-cable pressure barrier device (6) comprises an enclosure (6a) fitted with a breather valve (6b), the breather valve (6b) communicating with an inner volume of said enclosure (6a) comprisingatmospheric air, the enclosure (6a) comprising the exposed conducting core of the wire, the first part (6d 1 ) of said wire, the second part (6c2) of said wire and the resin part (6f), a comb (6e) being removably fixed to the enclosure (6a) in order to keep the wires separated, said comb (6e) comprising at least two teeth between which one wire is inserted, the comb (6e) is able to accommodate different wire gauges thanks to a variable spacing between the teeth.

6. On-cable pressure barrier device according to claim 3 or 5, wherein the comb (6e) is placed on the exposed conducting core (6d l , 6d2) of the wires.

7. On-cable pressure barrier device according to either claim 3 , 5 or 6, wherein two combs are provided, each comb being installed on one side of the exposed conducting core (6d l ,6d2) of the wires.

8. On-cable pressure barrier device according to either claim 2, 3, 5 to 7, wherein the enclosure (6a) comprises three parts, a first part (6al ) corresponding to half of the enclosure (6a), extending from the first part (3 c l ) of the cable to the second part (3 c2) of the cable, the other half of the enclosure (6a) being split in a second part (6a2) and a third part (6a3), the second part (6a2) extending to the second part (3 c2) of the cable, the third part (6a3 ) extending to the first part (3 c l ) of the cable.

9. Moto-compressor line comprising an on-cable pressure barrier device (6) according to either claim 1 to 8, wherein the moto- compressor line comprises a medium voltage junction box ( 1 ) connected to a control cabinet (2) by a first cable (2c) and to a moto-compressor (3) by a second cable (3 c l ,3 c2), each cable (2c,3 c l ,3 c2) comprising an insulating sheath (2d, 3 d) around at least two wires (2e, 3 e) individually insulated, the medium voltage junction box ( 1 ), the moto-compressor (3) and the second cable (3 c l ,3 c2) being located in an hazardous or explosible atmosphere, the control cabinet (2) and the first cable (2c) being located in a safe atmosphere, the on-cable pressure barrier device (6) being installed on the second cable (3 c l ,3 c2) in order to mitigate a gas diffusion from the moto-compressor (3 ) to the control cabinet (2) through the medium voltage junction box ( 1 ).

10. Manufacturing process of an on-cable pressure barrier device as described in the claims 2,3 , 5 to 7, comprising the following steps: a. determining a suitable location for the on-cable pressure barrier device (6) on the cable (3 c l ,3 c2), b. at the determined location, removing the insulating sheath (3 d) of the cable without cutting the wires (6c l ,6c2) compri sed therein, c. for each wire (6c l ,6c2) exposed by the removal of the insulating sheath (3 d) of the cable, removing a portion of the wire insulating sheath so that the conducting core (6d l ,6d2) is exposed, d. inserting the cable through gaskets (6g, 6h) provided on opposite faces of the enclosure first part, the cable residing inside each gasket (6g, 6h) so that the cable (3 c l ,3 c2) between said two gaskets (6g, 6h) i s at least partially free of its insulating sheath, e. installing a second part of enclosure (6a2) in order to form a hermetical seal with the first part of enclosure (6al ), f. pouring a curable resin in the enclosure (6a) so that a first part (6d l ) of the exposed conducting core of each wire is enclosed in resin along with the first part (6c l ) of each wire between said first exposed conducting core part (6d l ) and the first gasket (6g), said first gasket (6g) being in contact with the first part (3 c l ) of the cable extending from the on-cable pressure barrier device (6) to the medium voltage junction box ( 1 ), g. curing the resin.1 1 . Manufacturing process of an on-cable pressure barrier device as described in the claim 8, comprising the following steps: a. determining a suitable location for the on-cable pressure barrier device (6) on the cable, b. at the determined location, removing the insulating sheath (3 d) of the cable without cutting the wires (6c l ,6c2) compri sed therein,c. for each wire (6c l ,6c2) exposed by the removal of the insulating sheath (3 d) of the cable, removing a portion of the wire insulating sheath so that the conducting core (6d l ,6d2) is exposed, d. inserting the cable through gaskets (6g, 6h) provided on opposite faces of the enclosure first part, the cable residing inside each gasket (6g, 6h) so that the cable between said two gaskets (6g, 6h) is at least partially free of its insulating sheath, e. installing a second part of enclosure (6a2) so that a hermetical seal is achieved with first part of enclosure (6al ), f. pouring a curable resin in the enclosure (6a) so that a first part (6d l ) of the exposed conducting core of each wire is enclosed in resin along with the first part (6c l ) of each wire between said first exposed conducting core part (6d l ) and the first gasket (6g), said first gasket being in contact with the first part (3 c l ) of the cable extending from the on- cable pressure barrier device (6) to the medium voltage junction box ( 1 ), g. curing the resin then installing a third part of enclosure (6a3 ) so that a hermetical seal i s achieved with both the first part of enclosure and the second part of enclosure.

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