GB2528470A - A cable marking arrangement for electrical cables - Google Patents

Abstract

A cable marker arrangement for marking electrical cables for insertion into the housing of an electrical meter, comprising a marker element 22b with a collar having an external indicia 24b for indicating the electrical state of the cable, and an internal channel 35 extending from a first opening diameter 34 to a second opening diameter 40 that is smaller than the first in order to prevent passage of the sheath 30 of a cable through the collar while allowing internal wires 32 to pass through. There may be a second marker element that can be axially slideable along a cable to move into a locking abutment with the first marker element. Further defined is a marker element that comprises flexible arms (Fig 6, 54) interconnected at one end by a bridging section (Fig 6, 52), the free ends of the arms being expandable to receive and grip a cable.

Description

A CABLE MARKING ARRANGEMENT FOR ELECTRICAL CABLES

The present invention relates to a cable marking arrangement, and in particular to an arrangement for marking cables for connection to an electricity meter.

Electricity meters or energy meters are commonly used devices employed by utility companies for measuring the amount of electrical energy consumed by a residential or business property. Electricity meters connect directly to the power supply of a property and operate by continuously measuring the instantaneous voltage and current in order to calculate the electrical energy being used. Traditionally electromechanical induction watt-hour meters have been installed in properties, which includes a metal that is arranged to rotate at a speed proportional to the power passing through the meter. The number of revolutions of the disc is counted by a mechanical dial, and this number may be used to calculate the energy usage.

However, the energy usage measured by a traditional meter is entirely cumulative, and provides no information regarding the vary levels of usage and different times of the day, week or month. It is difficult for the consumer to determine on this information alone how their energy consumption may be moderated to reduce energy bills. Also, such traditional maters are stand alone devices that require direct reading bya member of the utility company in order to assess the energy consumption, and hence the cost of the energy consumed. This is inconvenient for the consumer and costly an inconvenient for the utility company.

Smart meters address these issues by measuring and recording electrical energy consumption of electric energy at frequent intervals and providing information of energy over time. The smart meters also include means to communicate that information both to the utility company and to the consumer for monitoring and billing purposes. The advantages of smart meters has resulted in a move to have smart meters installed in all homes in the UK by 2020. As such, there the number of installations has and will significantly increase over the coming years. Given the increase in the number of installations, guidelines have been developed to ensure that meter installation is performed in a manner that is safe and secure for the installer, as well as leaving the meter in a condition in which it is tamper free and presents no risk to the consumer.

S Installation guidelines for smart meters require that the electrical cables to and from the meter are clearly marked to indicate their live' or neutral' electrical state. It also a requirement that the outgoing cables are each provided with two separate markers in order to distinguish them from the in going cables. Currently cable tie markers are used to mark the cables. The use of cable ties generates material wastage and debris at the point of use as the ties must be cut to length once attached. There is currently no means for fixing the rotational position of the tie around the cables, which can result in rotation of the ties to an angle where the marker is not immediately readable. It is also not possible to remove and relocate cable ties as removal requires the ties to be cut.

is A further issue relating to smart meter installation, and the installation of electrical meters generally is ensuring that the opening through which the electrical cables are inserted into the meter is of sufficient size to accommodate the cable, while also preventing the insertion of additional cables or foreign objects into the meter. As electrical cables can vary is diameter, it is not possible to provide a universal opening that satisfies both these requirements.

It is therefore desirable to provide an improved cable marking system which addresses the above described problems and/or which offers improvements generally.

According to the present invention there is provided a (4) as described in the accompanying claims.

In an embodiment of the invention there is provided a cable marker arrangement for marking electrical cables for insertion into the housing of an electrical meter or other enclosure, the cables having a plurality of inner cables surrounded by an outer sheath, the arrangement comprising a marker element comprising a collar having an external indicia for indicating the electrical state of the cable to which it is connected, and an internal channel extending therethrough between first and second openings at corresponding first and second ends of the collar, the first opening having a first diameter and the second opening having a second diameter less than the first diameter, wherein S the channel is stepped in diameter along its length between the first and second diameters, the step in diameter defining an inerna I abutment to prevent passage of a cable sheath while allowing the internal cables to pass through to the second opening.

In this way, the first marker element forms a cap for the end of the cable arranged such that the inner cables are not visible or accessible at the first end which in use remains external to the meter. The second end is configured to be inserted into the opening of the meter corresponding to the relevant cable, and as such the free ends of the inner cables are externally shielded and only exposed within the enclosure of the meter. The second end is preferable configured to be received in the corresponding opening of the enclosure is with a close tolerance fit, which may be an interference fit, and includes a tapered leading edge to facilitate insertion.

The outer surface of the second end of the collar preferably has a reduced diameter for insertion into the opening the electrical meter enclosure, with the reduction in diameter defining an external abutment shoulder configured to prevent passage of the first end of the collar into the opening with first end extending outwardly of and obscuring the opening in use. As such, even if the second end does not closely fit within the opening to the meter, the opening is covered and obscured by the larger diameter first end of the collar to prevent additional cables or other objects from being inserted.

The channel preferably includes a third diameter section between the first and second diameter sections, the third diameter section having a diameter less than the first diameter and greater than the second diameter, wherein a first abutment shoulder is defined by the step between the first diameter section and the third diameter section, and a second abutment shoulder is defined between the third diameter section and the second diameter section, the first and third diameter sections being configured for accommodating two different sheath diameters. The wider first diameter accommodates larger cables, and preferably has a diameter of 25mm, with the free end of the sheath abutting the abutment shoulder between the first and third diameter sections. The third diameter section is preferably 16mm in diameter. 16mm cables inserted into the collar S pass through the first section and are spaced from the wider channel wall of this section.

The free end of the sheath then abuts the shoulder defined between the third and second channel sections. The second channel section is only wide enough to accommodate the inner cables.

The cable marker arrangement may further include a second marker element configured to be secured to a cable, the second marker element having an external indicia indicating the same electrical state as the indicia of the first marker element, the second marker element configured to be axially slideable along a cable to enable it to be moved into abutment with the first marker element, the first and second marker elements including cooperating locking means to rotationally fix the second mark element relative to the first marker element when the two are brought into axial abutment. The may alternatively or additionally be arranged to axially fix the first and second marker elements. Securing the first and second marker elements rotationally ensures that the indicia of both are visible from the same viewing angle. Axially abutting the first and second marker elements and holding them in this position ensures that it is immediately evident to the installation engineer that two markers are present on the cable, confirming that the cables are outgoing. In contrast, where cable ties are used it is possible that they may slide along the cable such that on first inspection it may appear that only one marker is present in the cable, giving a false impression of the nature of the cable.

One of the first and second marker preferably elements includes an axial projection and the other includes a corresponding axial recess configured to receive the projection arranged such that when the projection is received in the recess relative rotational movement between the two marker elements is prevented. The projection and recess may also be configured to axially secure the two markers together such as by including a close tolerance friction fit.

The projection and recess are preferably arranged to fix the first and second marker elements in a predetermined rotational relationship in which the indicia are arranged in predetermined manner, and preferably in a predetermined rotational relationship such S that the indicia of both elements are aligned.

The second marker element preferably comprises a pair of spaced flexible arms interconnected at one end by a bridging section, the free ends of the arms being expandable to receive a cable into the space defined between the two arms. This enables the marker to be secured to the cable in a quick and easy push fit manner that does not require material waste such as in the case of cable ties.

The arms may project from the bridging section in a first section and bend inwardly towards their ends such that the free ends extend in an opposing second direction, the is free ends of the arms being located inwardly of the proximal ends of the arms. The free ends flex towards the proximal ends on cable insertion, while the proximal ends also flex outwardly, thereby creating two inwardly directed biasing forces to grip the arms onto the cable. The inner edges of the free ends also face upwardly towards the bridging section when flexed creating an angled biasing force that clamps the cable in position.

The free ends of the arms are spaced from the bridging section The free ends of the arms include preferably barbs projecting inwardly and angled towards the bridging section in the second direction, which is in the direction of insertion and opposing the direction of retraction of the cable, to grip and retain a cable received within between the free ends of the arms.

The second marker element preferably further includes a locating arm extending across the space defined between the two arms in a direction substantially parallel with the bridging member and spaced inwardly towards the bridging section away from free ends of the arms, the locating arm being arranged to locate smaller cables in a position where they may be gripped by the free ends of the arms, and being flexible away from the free ends of the arms to accommodate larger cables. The locating arms is preferably curved to accommodate the curved surface of the cable. The arm ensures that smaller diameter cables, and specifically the 16mm cables are housed closely within the marker element S without passing so far in that they are not properly gripped by the gripping arms, and provides a returning biasing force to hold the cable in place. When the larger 25mm cable are inserted the locating arm flexes away towards the bridging section to provide greater space to accommodate the cable.

The locating arm preferably extends from the inner edge of one of the pair of arms, at a position spaced from the bridging section and the free ends of the arms in eth insertion direction, and extends laterally relative to the insertion direction towards the other arm, from which it is free and preferably spaced.

The first cable marker element is preferably a single piece moulded plastic component and the indicia is integrally moulded as part of marker element. The second cable marker element is also preferably a single piece moulded plastic component and the indicia is integrally moulded as part of marker element. As such the components are cheap to manufacture, and do not require multiple parts that can become separated and/or which require timely assembly at the point of use.

In another aspect of the invention there is provided a cable marking kit comprising a first pair of first and second cable marking elements as described above having indicia indicating a live cable condition, a second pair of first and second cable marking elements as described above having indicia indicating a neutral cable condition, and a pair of first cable marking elements as described above, one if which has an indicia indicating a live cable condition and the other of which has an indicia indicating a neutral cable condition.

In another aspect of the invention there is provided a cable marker arrangement comprising a pair of spaced resiliently flexible arms interconnected at one end by a bridging section, the free ends of the arms being expandable to receive a cable into the space defined between the two arms, and configured such that when expanded they impart a returning farce to grip the cable.

The arms preferably project from the bridging section in a first section and are bent S inwardly towards their ends such that the free ends extend in an opposing second direction, the free ends of the arms being located inwardly of the proximal ends of the arms.

The free ends of the arms may include barbs projecting inwardly and angled towards the bridging section in the second direction to grip and retain a cable received within between the free ends of the arms.

The second marker element may further include a locating arm extending across the space defined between the two arms in a direction substantially parallel with the bridging is member and spaced inwardly towards the bridging section away from free ends of the arms, the locating arm being arranged to locate smaller cables in a position where they may be gripped by the free ends of the arms, and being flexible away from the free ends of the arms to accommodate larger cables.

The locating arm preferably extends from the inner edge of one of the pair of arms and extends towards and is spaced from the other arm.

In another aspect of the invention there is provided a method of marking cables during installation of an electrical meter comprising; a) applying a first cable marker element as described above having an indicia indicative of a live cable condition to an ingoing live electrical cable having the cable prepared such that the inner cables extend past the end of the sheath by inserting the cable into the first cable marker element until the sheath abuts the abutment shoulder and the such that the inner cable extend out of the second opening; b) conducting step a) for the ingoing neutral cable wherein the first marker includes an indicia indicative of a neutral cable condition; c) conducting step a) for the outgoing live cable wherein the first marker includes an indicia indicative of a live cable condition; d) repeating step a) for the outgoing neutral cable wherein the first marker included an indicia indicative of a neutral cable condition; s e) applying a second marker element as described above having an indicia indicative of a live cable condition to the outgoing live cable and moving the first and second marker elements into abutment such that the cooperating rotational locking means rotationally fix the second mark element relative to the first marker element; and f) applying a second marker element as described above having an indicia indicative of a neutral cable condition to the outgoing neutral cable and moving the first and second marker elements into abutment such that the cooperating rotational locking means rotationally fix the second mark element relative to the first marker element.

The outer surface of the second end of the collar of the first marker elements preferably is has a reduced diameter for insertion into an opening an electrical enclosure, the reduction in diameter defining an external abutment shoulder configured to prevent passage of the first end of the collar into the opening with first end extending outwardly of and obscuring the opening in use and wherein step a) further includes inserting the second end of the first marker element into the corresponding opening of the enclosure of the electrical meter until the abutment shoulder abuts the surrounding outer surface of the enclosure and securing the free ends of the inner wires to the electrical meter when the first marker element is in the inserted position.

The present invention will now be described by way of example only with reference to the following illustrative figures in which: Figure 1 shows a smart meter including cable markers according S to an embodiment of the invention; Figure 2 shows a cable including a first marker element according to an embodiment of the invention; Figure 3 shows a plan view of a first marker element according to an embodiment of the invention; Figure 4 shows the first marker element of Figure 3 with a cable inserted; Figure 5 shows a first marker element according to an embodiment of the invention; Figure 6 shows a second marker element according to an embodiment of the invention; Figure 7 shows a first marker element and second marker element according to an embodiment of the invention in alignment; Figure 8 shows the first marker element and second marker element of Figure 7 in abutment; and Figure 9 shows a plan view of a first marker element and second marker element according to an embodiment of the invention in alignment.

Referring to Figure 1, a smart electrical meter 2 comprises an enclosure 4 that houses and contains metering means for monitoring electrical consumption and for transmitting that information to the utility company and to the consumer. The metering means comprises electrical connection terminals which connect to incoming and outgoing live and neutral S electrical cables. The incoming mains supply comprises a live cable 6 and neutral cable 8.

The incoming live 6 and neutral 8 enter the meter enclosure 4 through inlet openings 10 and 12 respectively and are secured to the terminals within the enclosure. The outgoing live cable 14 and neutral cable 16 leave the enclosure 4 via outlet openings 18 and 20 and connect to the power circuits of the property.

In accordance with installation guidelines, the cables 6, 8, 14 and 16 are each provided with a first cable marker 22a-d including an indicia 24a-d indicative of the electrical state of the cable, with a L' indicating the live cables and a N' indicating the neutral cables.

The outgoing live 14 and neutral 16 cables both include a second cable marker 26c and is 26d respectively having indicia 28c and 28d matching the indicia of the corresponding first cable marker 22. The presence of two cable markers indicates to the installer the outgoing cables.

As shown in Figure 2, each cable includes an outer insulating sheath 30 which surrounds a core comprising a plurality of electrically conductive wires 32. While figure 2 shows the incoming neutral cable 8, the same applies for the other cables 6, 14 and 16. The first cable marker 22b caps the cable 8. The cable 8 enters the first marker 22b through an opening 34 located at a first end of the marker 22b. The marker 22b includes a channel 35 extending through the marker 22b, such that the marker 22b is substantially cylindrical and defines a collar surrounding the cable 8. The first end of the channel 36 has a diameter that corresponds to the outer diameter of the sheath 30. The second end 38 has a reduced diameter that is less than the diameter of eth sheath 30. As such, in order for the cable to pass through the first marker 22b the cable 8 must be stripped to remove the sheath at its end exposing the inner wires 32, which are able to pass through the reduced diameter of the second opening 40 at the second end 38.

As shown in Figure 3, internally the channel 35 includes a first channel section 36 at the first end of the marker 22b comprising the largest diameter section of the channel which in the embodiment shown is 25mm, corresponding to the diameter of the cable sheath 30. The second channel section 38 at the second end has a second diameter less than the S first diameter that prevents the cable sheath from passing through. A third channel section 40 is located axially between the first 34 and second 38 sections. The third channel section 40 has a diameter that is less than the diameter of the first channel section 36 and greaterthan the diameter of the second channel section 38. In the embodiment shown the diameter of the third channel section 40 is 16mm.

The stepped reduction in diameter between the first channel section 36 and the third channel section 40 creates a first abutment shoulder 42. Similarly, the stepped reduction in diameter between the third channel section 40 and the second channel section 38 defines a second abutment shoulder 44. When a cable having a 25mm diameter sheath is is inserted into the first marker 22 it is accommodated within the first channel section 36 with the outer walls of the sheath 30 closely engaging the walls of the first channel section 36. One or more projections at 46 may extend radially into the first channel section 36 which locally deform the sheath 30 to key and rotationally lock the first marker 22 on to the cable. The axial end surface of the sheath 30 when fully inserted abuts the first abutment shoulder 42, which acts as a stop and prevents further axial travel of the sheath 30 through the marker 22, as shown in Figure 4. However the bundle of inner cables 32 have a combined diameter which is small enough to allow the cables to pass through the second channel section 38 and extend through the second end of the first marker 22 through the second opening 40.

The first marker 22 is also able to receive a 16mm diameter cable. In this arrangement the cable is received within the third channel section 42 without engagement with the walls of the first channel section 34. Again the third channel section 40 may include one or more radially extended projections 46 to rotationally restrain the cable. The end surface of the sheath 30 of the cable engages the abutment surface 42 and in the same way as described above prevents axial travel of the sheath 30 past the abutment shoulder 44 while permitting the inner cables 32 to extend through the second opening 40.

As shown in Figure 5 the second end 38 of the first marker elemnt 22 includes a reduced S external diameter which defines a cylindrical plug section 50. The reminder of the external surface of the first marker 22 has a greater diameter, with the stepped change in diameter between the plug section 50 at the second end and the main body section 52 defining a stepped abutment surface 54 facing axially in the direction of the second end 38. The plug section 50 is configured to be closely received within an opening of the enclosure 4, preferably with a friction fit, and includes a tapered leading edge 56 to facilitate insertion. The abutment surface 54 acts as a stop limiting axial travel of the plug section 50 into the opening through abutment with the outer surface of the enclosure 4.

When the plug section 50 is fully inserted into the opening of the enclosure the abutment surface 54 abuts the outer surface of the enclosure 4 with the main body section 52 is shielding and obscuring the opening. As such, additional cables or other objects may not be inserted into the opening, and the cables are internally shielded. As can also be seen from Figure 5, the indicia 24 comprises a raised letter indicating the electrical state of the cable that is integrally moulded with the first marker 22.

Figure 6 shows a second marker element 25 in plan view. The second marker 26 includes a bridge section 52 and a pair of flexible arms extending in a substantially perpendicular direction away from opposing ends of the bridge section 52. The flexible arms 54 are slightly convexly curved and include a proximal end section 56 and a distal end section 58.

The arms 54 are bent at an elbow 60 along their length through substantially 180 degrees such that distal ends 58 extend in a substantially opposite direction to the proximal ends 56 back towards the bridge section 52. The free ends 62 are spaced from the bridge section 52 and the distal end sections 58 are laterally spaced from each other defining an opening 64 into the space 66 defined between the arms 54 and the bridge 52. The distal ends 58 include barbs 68 located on their inner edges with the barbs of each distal end 58 facing each other. The barbs 68 are angled inwardly towards the bridge section 52 in the insertion direction as indicated by arrow A. In use the marker 26 is pushed on to a cable such that the cable is received within the opening 64. The opening 64 in the closed configuration is significantly narrower than the diameter of the cable to which it is applied. As the second marker 26 is pushed over the cable the arms 54 flex outwardly in a lateral direction as indicated by the arrows B substantially parallel to the length of the S bridging section 52 and perpendicular to the insertion direction A. The proximal ends 56 extend outwardly pivoting about their connection with the bridge section 52.

The distal ends 58 also pivot about the elbows 60 in the direction B and compress reducing the distance C between their tips 62 and the proximal ends 56 of the arms.

When the cable is fully received within the second marker 26 the resilient arms 54 in their expanded configuration provide a returning force which clamps the arms against the cable. The compressed distal ends 58 are angled in the flexed form such that the end surfaces angle inwardly in the insertion direction A with the cable being inserted a sufficient distance in to the marker 26 that part of the inner surface of the distal sections is 56 engage the rear side of the cable relative to the insertion direction A urging the cable into the second marker 26, with the barbs 68 assisting to prevent retraction of the cable.

A locating arm 70 is provided within the marker 26 proximate the bridging section 52.

The locating arm 70 has a curved profile and is secured at its base to one of the arms 54 and extends across the void within the marker 26 towards the other arm 54 with the end of the locating arm 70 being spaced from the other arm 54. The locating arm 70 is flexible and able to flex in the insertion direction A towards the bridging section 52. The locating arm 70 provides a stop for smaller 16mm cables. If such smaller cables were to be inserted all the way into the marker such that they abutted the bridge 52 then they would not be adequately gripped by the distal ends 58 of the arms 54. The locating arm 70 limits insertion of the cable and provides a returning biasing force against the cable in a direction opposing the insertion direction A, thereby clamping the cable between the distal ends 58 and the arm 54 and the locating arm 70. Where a large 25mm cable is inserted into the marker 26 the locating arm is able to flex rearwardly towards the bridging section 52 to accommodate the larger cable.

As shown in Figure 7 the front surface of the marker 26 includes an integrally moulded alpha numeric indicia indicating the electrical condition of the cable to which it is attached. The axially facing upper surface 32 includes axial projection 74 in the form of an elongate spigot. The spigot 74 is configured to be received in a corresponding axially S extending recess of the lower surface of 78 of the corresponding first marker 22. The spigot 74 and the recess 76 are located such that when the spigot 74 is received in the recess of 76 the indicia of the first 22 and second 26 markers are aligned. When the spigot 74 is received in the recess 76, relative rotation between the first 22 and second 26 markers is prevented. A friction fit may also be provided between the spigot 74 and the recess 76 such that the two markers are axially held together.

As shown in Figure 8, when the first 22 and second 26 markers are abutting with the spigot 74 received in the recess of 76 the indicia are co-aligned and it is immediately evident that two markers are provided on the cable. With the cable secured within the enclosure 4 to the electrical terminals the first marker 22 is held in position against the enclosure with the abutment shoulder 54 obscuring the opening. As such, the first marker 22 is axially fixed on the cable and cannot slide out of view. Sliding the second marker 26 into abutment and securement with the first marker also holds the second marker 26 in a position where the indicia is readily viewable at a common viewing angle to the indicia of the first marker 22, as well as preventing the second marker 26 from sliding away from the first marker 22 along with the cable.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.