Electricity meter connection module

Abstract

A pre-assembled module for connecting to a current transformer electricity meter 105 comprises a current transformer 101, a shorting link 103 and a voltage isolator 104. The shorting link is connected

Description

Technical Field The present invention relates to devices and methods for connecting electricity meters to mains electricity supplies. Background Mains electricity meters need to be routinely replaced due to scheduled replacement cycles, unexpected failures, or new meter technologies or standards being rolled out. Low-current mains electricity supplies (typically less than 100 amps) generally use whole current (WC) electricity meters. Whole current electricity meters are connected in series after the cut-out fuse of an end user’s mains electricity supply. Because whole current electricity meters are connected in series, safely replacing a whole current electricity meter requires the end user’s mains electricity supply to be disconnected while the replacement work is carried out. This periodic loss of mains electricity causes significant inconvenience and operational disruption to end users. Commercial end users, such as banks, pharmacies and light industrial users, are particularly inconvenienced by regular power outages, which result in costly downtime and service interruptions, and which often require careful contingency plans to be put in place. High-current mains electricity supplies (typically exceeding 100 amps) for large commercial or industrial end users typically use current transformer (CT) electricity meters. CT metering is preferred for high-current supplies because it reduces the amount of current that passes directly through the meter. However, CT metering systems for high-current applications often involve large and complex assemblies, including sizable transformers and safety enclosures. This makes them impractical for use in lower current settings where space is typically constrained. Additionally, existing high-current systems generally still require a full power shutdown during servicing. Summary of the Invention In accordance with a first aspect of the invention, there is provided a pre-assembled module for connecting a current transformer electricity meter to a mains electricity supply. The module comprises at least one current transformer comprising a first secondary winding terminal and a second secondary winding terminal, the current transformer configured to generate a current proportional to the current flowing through a live mains electricity cable of the mains electricity supply. The module further comprises at least one shorting link comprising a first input terminal connected to the first secondary winding terminal and a second input terminal connected to the second secondary winding terminal, wherein the shorting link is selectively actuatable to create an electrical short across the first and second input terminals. The module further comprises at least one voltage isolator comprising a first input terminal and a second input terminal, wherein the first input terminal is connectable to a live mains electricity cable of the mains electricity supply and the second input terminal is connectable to a neutral mains electricity cable of the mains electricity supply, wherein the voltage isolator is selectively actuatable to electrically isolate the live mains electricity cable. The shorting link and the voltage isolator each comprise at least two output terminals that are connectable to a current transformer electricity meter, and wherein the shorting link and the voltage isolator are configured such that, when the shorting link and voltage isolator are selectively actuated, the output terminals are electrically isolated to allow an electricity meter to be disconnected from the output terminals without interrupting the mains electricity supply. Optionally, the module is an electricity meter conversion module for converting a mains electricity supply from whole current electricity metering to current transformer electricity metering. Optionally, the current transformer has a rating of 100:5. Optionally, the mains electricity supply is a single-phase supply, and the module comprises one current transformer, one shorting link and one voltage isolator. Optionally, the mains electricity supply is a three-phase supply, and the module comprises a three-phase voltage isolator, three current transformers and three shorting links, the current transformers and shorting links each associated with a respective phase of the three-phase supply. Optionally, the module comprises a housing and a removeable lid. Optionally, the module is wall mountable. Optionally, the current transformer is a solid core or a split core current transformer. Optionally, the module further comprises a test block, and wherein the test block comprises the at least one shorting link and voltage isolator. Optionally, the module further comprises a control unit connectable to one or more sensors, wherein the control unit is configured to receive output signals from the one or more sensors, process the output signals and generate corresponding signal data. Optionally, the module further comprises a wireless data transceiver connected to the control unit and configured to communicate the signal data to a remote receiver for processing by a remote computing system. Optionally, the module further comprises a current sensor connectable to a live mains electricity cable of the mains electricity supply and arranged to detect current flow in the electricity cable. Optionally, the module further comprises at least one of: a humidity sensor and a temperature sensor located within the housing. In accordance with a second aspect of the invention there is provided a method of connecting a current transformer electricity meter to a mains electricity supply. The method comprises: installing a pre-assembled module comprising at least one current transformer, at least one shorting link and at least one voltage isolator at a mains electricity supply, wherein the current transformer comprises a first secondary winding terminal and a second secondary winding terminal, and wherein the first secondary winding terminal is connected to a first input terminal of the shorting link, and the second secondary winding terminal is connected to a second input terminal of the shorting link; installing a current transformer electricity meter adjacent to the module; passing a live mains electricity cable of the mains electricity supply through the current transformer; connecting a live mains electricity cable of the mains electricity supply to a first input terminal of the voltage isolator and a neutral mains electricity cable of the mains electricity supply to a second input terminal of the voltage isolator; connecting a first output terminal and a second output terminal of the shorting link to the current transformer electricity meter; and connecting a first output terminal and a second output terminal of the voltage isolator to the current transformer electricity meter. Optionally, the method further comprises the step of: disconnecting a whole current electricity meter from the live and neutral mains electricity cables of the mains electricity supply. Optionally, the method is a method of converting a mains electricity supply from whole current electricity metering to current transformer electricity metering. Optionally, the step of passing a live mains electricity cable through the current transformer comprises passing a powered live mains electricity cable through a split core current transformer. Optionally, the step of connecting a live and neutral mains electricity cable to the first and second input terminals of the voltage isolator further comprises: connecting a first end of a first tapping cable to the first input terminal of the voltage isolator; connecting a first end of a second tapping cable to the second input terminal to the voltage isolator; connecting a second end of the first tapping cable to a powered live mains electricity cable by tapping the powered live mains electricity cable; and connecting a second end of the second tapping cable to a neutral mains electricity cable by tapping the neutral mains electricity cable. Advantageously, in accordance with embodiments of the invention, a pre-assembled module is provided that, when installed, enables a current transformer electricity meter to be safely disconnected and reconnected without interrupting the mains electricity supply to an end user. This avoids the need for costly and inconvenient power outages during meter servicing or replacement. The module is supplied in a pre-assembled form, which facilitates rapid and convenient installation. Because the module is pre-assembled, its design can be pre-approved by mains supply operators, supporting regulatory compliance and standardisation. The pre-assembly of the module also enables a structured and repeatable installation process, which can improve safety and reliability while reducing installation time and complexity. The compact size of the module allows installation in space-constrained environments. The module is particularly suitable for retrofitting at low-current mains electricity supplies to convert them from whole current electricity metering to current transformer electricity metering. Due to its compact form, such conversions can be carried out with minimal modification to the existing components of the mains electricity supply. In certain embodiments, a method of installation is provided which allows the module itself to be installed without interrupting the mains electricity supply. This further improves convenience for the end user during retrofitting because neither the installation of the module, nor subsequent meter replacements, require disruption of the electricity supply. 5 Various further features and aspects of the invention are defined in the claims. Brief Description of the Drawings Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings where like parts are provided with corresponding reference numerals and in which: Figure 1 is a simplified schematic diagram showing a module arranged in accordance with certain embodiments of the invention installed at a mains electricity supply at an end user’s premises; Figure 2 is a simplified schematic diagram showing a further module arranged in accordance with certain embodiments of the invention; Figure 3 is a simplified schematic diagram showing the module of Figure 1 installed in an alternative configuration at a mains electricity supply at an end user’s premises; Figure 4 is a simplified schematic cross-sectional diagram showing the module of Figure 1 installed at an end user’s premises; Figure 5 is a simplified schematic diagram showing a telemetry module that can be included as part of the module of Figure 1 or Figure 2 in accordance with certain embodiments of the invention; and Figure 6 is a simplified schematic diagram showing a remote system arranged to exchange data with the wireless data transceiver of the telemetry module of Figure 5. Detailed Description Figure 1 is a simplified schematic diagram showing a module arranged in accordance with certain embodiments of the invention installed at a mains electricity supply at an end user’s premises. The module comprises a housing 100 within which is located a current transformer 101 and a test block 102. The test block comprises a shorting link 103 and a voltage isolator 104. Figure 1 shows the module after it has been installed and connected to a current transformer electricity meter 105, a cut-out fuse 106 and an end user electricity supply 107. The module housing 100 is typically composed of plastic or metal and comprises a removable lid. The housing 100 is configured to be mounted to a wall or other fixed surface using mechanical fasteners such as screws or bolts. Advantageously, the wall mounting of the module enables installation in existing meter cupboards, utility boards, or confined spaces without requiring structural modification to the existing setup to facilitate retrofitting. The housing 100 typically includes apertures to permit the routing of electrical cables into and out of the enclosure. In some embodiments, the apertures may be fitted with grommets or cable glands to provide strain relief and environmental sealing. The current transformer 101, shorting link 103 and voltage isolator 104 are typically mounted to one or more DIN rails located inside the housing 100. The DIN rails facilitate modular assembly, standardisation, and ease of component replacement. In certain embodiments, the housing 100 has a length and / or a width of less than 25cm, and / or a depth of less than 15cm. In certain embodiments, the housing 100 has dimensions equal to or smaller than those of a standard low-current (<100 amp) electricity meter. Advantageously, the housing 100 is compact enough to be retrofitted to an existing mains electricity supply board. The current transformer 101 can be a solid-core or a split-core type. When installed, the current transformer 101 receives a live mains electricity cable through a central aperture. The current transformer 101 includes primary and secondary windings. The current transformer 101 is configured to generate a current in the secondary winding that is proportional to the current flowing through the live mains electricity cable. The secondary winding of the current transformer 101 is terminated at a pair of secondary winding terminals. In certain embodiments, the current transformer 101 has a rating of 100:5. This means that when 100 amps flows through the primary winding, it will generate 5 amps in the secondary winding. The meter 105 has a rating corresponding to the current transformer 101. In certain embodiments, the current transformer 101 is rated to a maximum current of 100 amps. This standard ratio ensures compatibility with low-current current transformer electricity meters and simplifies calibration and billing accuracy. In certain embodiments, the current transformer 101 is MID approved. As will be understood, MID approval refers to the Measuring Instruments Directive (MID 2014 / 32 / EU) Ell approval process for electricity meters. Advantageously, this ensures that the current transformer 101 operates in a standardised manner, for example to ensure accurate end user billing. The shorting link 103 includes a pair of input terminals and a pair of corresponding output terminals. In the pre-assembled condition, the input terminals are electrically connected to the secondary winding terminals of the current transformer 101 by respective cables. When installed, the output terminals are electrically connected by the installer to the meter 105 by a further pair of cables. The shorting link 103 is selectively actuatable between an open state and a closed state. In the open state, the shorting link 103 provides an electrical connection between the input and output terminals. This allows electrical current to flow through a circuit between the current transformer 101 and meter 105. In the closed state, the shorting link 103 creates an electrical short circuit between the two input terminals, thereby short-circuiting the secondary winding of the current transformer 101. This configuration allows the output terminals to be safely electrically isolated from the current transformer 101. It will be understood that various types of shorting link can be used. In certain embodiments, the shorting link 103 comprises a moveable piece of conductor, and selectively actuating the shorting link 103 between the open and closed state involves moving the piece of conductor between a position where the electrical short circuit is created and a position where it is broken. The voltage isolator 104 includes a pair of input terminals and a pair of output terminals. When installed, the input terminals are connected to live and neutral cables of the mains electricity supply. When installed, the output terminals are connected to the meter 105 by a respective pair of cables. The voltage isolator 104 comprises an actuatable fuse or circuit breaker associated with the live cable and a fixed or removable link associated with the neutral cable. The voltage isolator 104 is selectively actuatable via the actuatable fuse or circuit breaker to electrically isolate the output terminals from the live mains electricity cable. The voltage isolator is also known as a potential fuse and link. The module is pre-assembled at a location remote from the installation site. For example, the module can be pre-assembled at a manufacturing facility. During pre-assembly, the current transformer 101 and the test block 102 are mounted within the housing 100 and the current transformer 101 is electrically connected to the shorting link 103. The pre-assembled configuration allows for standardised installation, reducing installation time and improving safety and consistency across installations. The pre-assembled configuration also allows the design of the module to be certified according to the relevant standards. Figure 4 is a simplified schematic cross-sectional diagram showing the module of Figure 1 during installation at an end user’s premises. Figure 4 shows the housing 100 secured to a wall 400. The housing 100 is sealed by a removeable lid 401. Advantageously, the removeable lid 401 provides a convenient way of accessing the inside of the housing 100 during installation and subsequent electricity meter replacements. The current transformer 101, shorting link 103 and voltage isolator 104 are located inside the housing 100. The module also includes an optional telemetry module 402 located within the housing 100. The telemetry module 402 is described in more detail herein with reference to Figure 5. The current transformer 101, shorting link 103, voltage isolator 104 and telemetry module 402 are mounted to a mounting structure 403. Typically, the mounting structure 403 is a DIN rail secured to an inner surface of the housing 100. The shorting link 103 is pre-connected to the current transformer 101 in the manner described above by a pair of cables 404. Returning to Figure 1, a method of installing the module will now be described. In certain embodiments, the installation methods described herein are carried out in accordance with BS7671 (18th Edition) wiring regulations. The method begins by installing the pre-assembled module at the site of the mains electricity supply, for example in a meter cupboard. As described above, the module is delivered to the site assembled with internal wiring between the current transformer 101 and the shorting link 103 already made. The installer mounts the module to a wall or other fixed surface using mechanical fasteners, such as screws or bolts. The installer also installs a current transformer electricity meter 105 adjacent to the module. The installer passes a live mains electricity cable through the central aperture of the current transformer 101. Depending on the type of current transformer used, this may involve threading the cable through a solid-core transformer before termination or clamping a splitcore transformer around an already-installed cable. The secondary winding terminals of the current transformer 101 are already pre-connected to the input terminals of the shorting link 103. These connections are typically made using insulated cables with crimped or screw-secured connectors. This wiring allows the secondary current generated by the current transformer 101 to be routed through the shorting link 103 before reaching the meter 105. The installer connects the voltage isolator 104 to the mains electricity supply. This involves connecting live and neutral conductors of the mains electricity supply to the input terminals of the voltage isolator 104. In the example shown in Figure 1, the cut-out fuse 106 has two live and two neutral mains cables. One of these live-neutral pairs is connected to voltage isolator 104 and the other is connected to the end user supply 107 via the current transformer 101. The installer connects the output terminals of the shorting link 103 to respective terminals of the electricity meter 105 using a pair of cables. This allows the meter to receive the current from the current transformer 101. The installer connects the output terminals of the voltage isolator 104 to respective terminals of the meter 105 using another pair of cables. These connections provide the voltage reference required for the meter to calculate power and energy consumption. The steps may be performed in any suitable order, depending on installation constraints. In certain embodiments, the module is installed for a new mains electricity supply, in which case there is no legacy whole current electricity meter to disconnect. In other embodiments, the module is used for converting a mains electricity supply from whole current electricity metering to current transformer electricity metering. In such embodiments, typically the method first includes electrically isolating the mains electricity supply at the customer’s main fuse 106, removing the whole current meter, and connecting the module as described above, before restoring the mains electricity supply. However, in other embodiments, the module itself can be installed without interrupting the mains electricity supply. Such a method is described below with reference to Figure 3. Figure 3 is a simplified schematic diagram showing the module of Figure 1 installed in an alternative configuration at a mains electricity supply at an end user’s premises. The module has been installed at a site to convert a mains electricity supply from whole current electricity metering to current transformer electricity metering without interrupting the mains electricity supply to the end user during the installation method. The module and meter 105 are connected in series with a deactivated legacy whole current electricity meter 300. The module corresponds with the module described with reference to Figure 1 except as otherwise described and depicted. The method of installing the module also generally corresponds with the method described with reference to Figure 1 except as otherwise described below. The mains electricity supply is not isolated during module installation. The installer passes the live mains electricity cable through the current transformer while it is powered. That is, without isolating the live mains electricity cable from the mains electricity supply such that current is flowing through the live mains electricity cable. This requires the use of a split core current transformer to clamp around the cable because the powered cable cannot safely be cut while it is powered. The installer connects the meter 105 to the shorting link 103 and voltage isolator 104 using respective pairs of cables in the manner described above. The step of connecting the live and neutral mains electricity cables to the voltage isolator 104 involves the following further steps. The installer connects a first end of a first tapping cable 301 to the first input terminal of the voltage isolator 104. The installer connects a first end of a second tapping cable 302 to the second input terminal of the voltage isolator 104. The second ends of the first and second tapping cables 301 302 include respective first and second voltage clamps 303 304. As will be understood, voltage clamps are devices with teeth that can pierce the insulation of an electrical cable to make an electrical connection. The installer uses the voltage clamps 303 304 to pierce the insulation of the powered live and neutral electrical cables. That is, the installer uses the voltage clamps 303 304 to tap in to the live and neutral electrical cables without first isolating them from the mains electricity supply. Typically, the legacy whole current meter 300 remains physically installed but electrically deactivated and may be labelled as redundant. After installation, the module operates in the same manner as the module described with reference to Figure 1. Advantageously, this installation technique enables a mains electricity supply to be converted from whole current electricity metering to current transformer electricity metering without any interruption in mains electricity supply to the end user either during the conversion process or during subsequent electricity meter changes. Advantageously, this can avoid any interruptions to an end user’s mains electricity supply. Once the module is installed in the manner depicted in Figure 1 or Figure 2, the meter 105 can be replaced without interrupting the mains electricity supply. To do so, a user selectively actuates the shorting link 103 and the voltage isolator 104 to electrically isolate their respective output terminals from the current transformer 101 and the mains electricity cables. In this configuration, the meter 105 can be disconnected from the output terminals and a new meter connected, before the shorting link 103 and voltage isolator 104 are selectively actuated to restore the electrical connection with the current transformer 101 and mains electricity cables. In certain embodiments, the module is configured to operate with a mains electricity supply of 100 amps or less. While the embodiments described above depict a neutral mains electricity cable passing from the cut-out fuse 106 to the end user supply 107 without passing through the module housing 100, in certain embodiments, the neutral mains electricity cable can pass through the module housing. In the embodiments described with reference to Figures 1 and 2, the shorting link 103 and voltage isolator 104 are integrated with a test block 102. The test block is a modular assembly that includes both a voltage isolator and a shorting link used to facilitate safe meter disconnection and testing. However, in other embodiments, the module does not include a test block, and the shorting link 103 and voltage isolator 104 are provided separately. In the embodiments described with reference to Figures 1 and 2, the mains electricity supply is a single-phase supply, and the module includes one current transformer, one shorting link and one voltage isolator. Advantageously, the single-phase configuration enables compact installation in residential or light commercial settings where space is limited. However, in other embodiments, the module can be configured for use with a three-phase mains electricity supply as described below with reference to Figure 2. Figure 2 is a simplified schematic diagram showing a further module 200 arranged in accordance with embodiments of the invention. The module 200 substantially corresponds to the module described with reference to Figure 1 except in that it is modified for use with a three-phase mains electricity supply. As will be understood, a three-phase mains electricity supply typically includes three live cables and one neutral cable. The module 200 comprises three current transformers 201a 201b 201c. The module also comprises a test block 202 comprising three shorting links 203a 203b 203c and a three-phase voltage isolator 204 comprising three live input terminals and one neutral input terminal. Each of the current transformers 201a 201b 201c is connectable to its own live mains electricity cable and is configured to generate a current proportional to the current flowing through the respective cable. Each current transformer 201a 201b 201c is connected to a respective shorting link 203a 203b 203c in the same manner as described with reference to Figure 1. The three-phase voltage isolator 204 is connected to the three live and one neutral mains electricity cables in the manner described with reference to Figure 1. The three-phase voltage isolator 204 comprises four corresponding output terminals. In use, the output terminals of the shorting links 203a 203b 203c and the voltage isolator 204 are connected to respective terminals of a three-phase current transformer electricity meter. The three-phase module can be installed in accordance with the methods described herein. In addition to the method of Figure 1, the three-phase module can also be installed in accordance with the live install method described with reference to Figure 3. In certain embodiments, the three-phase voltage isolator comprises three separate voltage isolators and a neutral link. Figure 5 is a simplified schematic diagram showing a telemetry module 402 that can be included as part of a module in accordance with embodiments of the invention. The telemetry module 402 is located inside the housing 100. The telemetry module 402 can be included in any of the modules described herein. The telemetry module 402 comprises a processor 501, a battery 502, a wireless data transceiver 503 with an associated wireless antenna 504, and sensors 505. The battery 502, wireless data transceiver 503 and sensors 505 are connected to the processor 501. The telemetry module 402 can also comprise memory connected to the processor. The processor 501 is configured to receive output signals from the sensors 505, process the signals, and generate corresponding signal data. The processor 501 is also configured to store the signal data locally and / or to transmit it to a remote system via the wireless data transceiver 503. The wireless data transceiver 503 is configured to transmit signal data to a remote system for further analysis or logging. The wireless data transceiver 503 can use any suitable wireless communication protocol, including but not limited to Wi-Fi, LoRa, Zigbee, NB-loT, or cellular (e.g., 4G / 5G). The sensors 505 include one or more environmental and / or electrical monitoring sensors. In certain embodiments, the sensors 505 include a current sensor which is arranged to detect current flow in a live mains electricity cable. In certain embodiments, the current sensor can be a current clamp. In certain embodiments, the processor 501 is configured to receive the current signals from the current sensor, to generate corresponding current data and transmit the current data to a remote system. In certain embodiments, the processor 501 is further configured to process the current data to determine a current spike, and to generate a corresponding tamper alert to transmit to the remote system. A current spike may be indicative of tampering or energy theft. In some embodiments, the sensors 505 comprise a temperature sensor and / or a humidity sensor located within the housing 100. These sensors are configured to detect elevated internal temperatures or moisture levels that may indicate overheating, condensation, or ingress of water. The processor 501 can be configured to generate a maintenance or safety alert if the measured values exceed predefined thresholds for transmission to the remote system 600. Alternatively or additionally, the processor 501 can be configured to transmit the sensor data to the remote system. These sensor-based monitoring functions may be used individually or in combination to provide enhanced operational safety, support preventative maintenance, and enable remote diagnostics. In certain embodiments, the telemetry module 402 does not include a battery. In such embodiments, the telemetry module 402 is arranged to receive power from the mains electricity supply. Figure 6 is a simplified schematic diagram showing a remote system 600 arranged to exchange data with the wireless data transceiver 503. The remote system 600 includes a wireless antenna, a cloud server and a user interface. The remote system 600 comprises a wireless antenna configured to receive signal data transmitted by the wireless data transceiver 503. The wireless antenna is connected to a cloud server, which is configured to receive, store, and process the data received from the telemetry module 402. The cloud server may apply analytics, generate alerts, and maintain historical logs of sensor readings. The remote system 600 also includes a user interface, which may be accessed via a web portal or mobile application. The user interface allows authorised users to view real-time and historical sensor data, receive alerts, and configure system parameters such as sensor thresholds or notification preferences. In certain embodiments, the remote system 600 may be integrated with a broader smart metering or energy management platform, allowing cross-verification of data between the telemetry module 402 and the electricity meter 105. In certain embodiments, the remote system 600 is configured to receive the current data from the telemetry module 402 and to compare the current data with electricity consumption data received independently from an electricity meter fitted at the same mains electricity supply. The remote system 600 can be further configured to generate a tamper alert if the current data and the electricity meter data diverge significantly. Advantageously, the telemetry module 402 and remote system 600 facilitate remote management of an electricity meter network. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. With respect to the use of substantially any plural and / or singular terms herein, those having skill in the art can translate from the plural to the singular and / or from the singular to the plural as is appropriate to the context and / or application. The various singular / plural permutations may be expressly set forth herein for sake of clarity. It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., “a” and / or “an” should be interpreted to mean “at least one” or “one or 5 more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or more recitations). 10 It will be appreciated that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope being indicated by the 15 following claims.

Claims

1. A pre-assembled module for connecting a current transformer electricity meter to a mains electricity supply, the module comprising:at least one current transformer comprising a first secondary winding terminal and a second secondary winding terminal, the current transformer configured to generate a current proportional to the current flowing through a live mains electricity cable of the mains electricity supply;at least one shorting link comprising a first input terminal connected to the first secondary winding terminal and a second input terminal connected to the second secondary winding terminal, wherein the shorting link is selectively actuatable to create an electrical short across the first and second input terminals; andat least one voltage isolator comprising a first input terminal and a second input terminal, wherein the first input terminal is connectable to a live mains electricity cable of the mains electricity supply and the second input terminal is connectable to a neutral mains electricity cable of the mains electricity supply, wherein the voltage isolator is selectively actuatable to electrically isolate the live mains electricity cable;wherein the shorting link and the voltage isolator each comprise at least two output terminals that are connectable to a current transformer electricity meter, and wherein the shorting link and the voltage isolator are configured such that, when the shorting link and voltage isolator are selectively actuated, the output terminals are electrically isolated to allow an electricity meter to be disconnected from the output terminals without interrupting the mains electricity supply.

2. A module as claimed in claim 1, wherein the module is an electricity meter conversion module for converting a mains electricity supply from whole current electricity metering to current transformer electricity metering.

3. A module as claimed in claim 1 or claim 2, wherein the current transformer has a rating of 100:5.

4. A module as claimed in any previous claim, wherein the mains electricity supply is a single-phase supply, and the module comprises one current transformer, one shorting link and one voltage isolator.

5. A module as claimed in any of claims 1 to 3, wherein the mains electricity supply is a three-phase supply, and the module comprises a three-phase voltage isolator, three currenttransformers and three shorting links, the current transformers and shorting links each associated with a respective phase of the three-phase supply.

6. A module as claimed in any previous claim, wherein the module comprises a housing and a removeable lid.

7. A module as claimed in any previous claim, wherein the module is wall mountable.

8. A module as claimed in any previous claim, wherein the current transformer is a solidcore or a split core current transformer.

9. A module as claimed in any previous claim, further comprising a test block, and wherein the test block comprises the at least one shorting link and voltage isolator.

10. A module as claimed in any previous claim, wherein the module further comprises a control unit connectable to one or more sensors, wherein the control unit is configured to receive output signals from the one or more sensors, process the output signals and generate corresponding signal data.

11. A module as claimed in claim 10, wherein the module further comprises a wireless data transceiver connected to the control unit and configured to communicate the signal data to a remote receiver for processing by a remote computing system.

12. A module as claimed in claim 10 or 11, further comprising a current sensor connectable to a live mains electricity cable of the mains electricity supply and arranged to detect current flow in the electricity cable.

13. A module as claimed in any of claims 10 to 12, wherein the module further comprises at least one of: a humidity sensor and a temperature sensor.

14. A method of connecting a current transformer electricity meter to a mains electricity supply, the method comprising:installing a pre-assembled module comprising at least one current transformer, at least one shorting link and at least one voltage isolator at a mains electricity supply, wherein the current transformer comprises a first secondary winding terminal and a second secondary winding terminal, and wherein the first secondary winding terminal is connected to a first inputterminal of the shorting link, and the second secondary winding terminal is connected to a second input terminal of the shorting link;installing a current transformer electricity meter adjacent to the module;passing a live mains electricity cable of the mains electricity supply through the current transformer;connecting a live mains electricity cable of the mains electricity supply to a first input terminal of the voltage isolator and a neutral mains electricity cable of the mains electricity supply to a second input terminal of the voltage isolator;connecting a first output terminal and a second output terminal of the shorting link to the current transformer electricity meter; andconnecting a first output terminal and a second output terminal of the voltage isolator to the current transformer electricity meter.

15. A method as claimed in claim 14, further comprising the step of: disconnecting a whole current electricity meter from the live and neutral mains electricity cables of the mains electricity supply.

16. A method as claimed in claim 14 or claim 15, wherein the method is a method of converting a mains electricity supply from whole current electricity metering to current transformer electricity metering.

17. A method as claimed in claim 16, wherein the step of passing a live mains electricity cable through the current transformer comprises passing a powered live mains electricity cable through a split core current transformer.

18. A method as claimed in claim 17, wherein the step of connecting a live and neutral mains electricity cable to the first and second input terminals of the voltage isolator further comprises:connecting a first end of a first tapping cable to the first input terminal of the voltage isolator;connecting a first end of a second tapping cable to the second input terminal to the voltage isolator;connecting a second end of the first tapping cable to a powered live mains electricity cable by tapping the powered live mains electricity cable; andconnecting a second end of the second tapping cable to a neutral mains electricity cable by tapping the neutral mains electricity cable.T +44(0)30 0300 2000

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