Electric meter with thermal protection

Abstract

An electricity meter (100) for connecting with a utility power line and a load via a meter seating device and for determining power consumption between the utility power line and the load. An electricity meter (100) includes a base plate (102) including at least one blade (114a-114d) configured to couple with a corresponding jaw of an instrument seating device to electrically connect the electricity meter (100) with a utility power line and a load; a service switch (140) operable to enable or disable an electrical connection between the utility power line and the electricity meter (100). The backplane (102) further includes a thermal device (126a, 126b) located proximate to the at least one blade (114a-114d) and configured to control the service switch (140) to disable an electrical connection between the utility power line and the electricity meter (100) if a temperature of the thermal device (126a, 126b) exceeds a temperature threshold.

Description

[0001] Related Applications

[0002] This application claims priority to UK patent application serial number 2218912.0 filed on December 15, 2022, which is incorporated herein in its entirety. Technical Field

[0003] The present disclosure relates to an electric meter for connecting to a utility power line and a load via a meter placement device. Background Art

[0004] An electric meter or metering device measures the electrical energy or power consumption between the utility line and the load to determine the amount of electrical energy or power consumed by a residence, business, or electrically powered device.

[0005] In a typical residential installation, an electric meter is attached to the utility line and load via a meter mounting device (or meter socket). The electric meter includes a base plate that includes (one or more) electrical contacts, specifically blades. The blades connect to corresponding utility power line and load clamps in the meter mounting device to connect the electric meter to the power line and load, respectively, and allow the load current and load voltage to be measured. When the electric meter is connected to the meter mounting device, a large amount of current flows through the blades of the base plate.

[0006] Typically, in residential installations, the meter mounting device and the connected electric meter are mounted outdoors, and therefore the jaws of the meter mounting device and the blades of the electric meter may be exposed to the external environment (e.g., extreme temperatures, moisture, etc.). It is not uncommon for the jaws of the meter mounting device to degrade during the service life of the meter mounting device. In some cases, the jaws may degrade to such an extent that a non-negligible resistance is introduced into the connection between the jaws of the meter mounting device and the blade(s) of the base plate of the electric meter. This may further lead to temperature increase and overheating of the electric meter (and in particular the blade(s) and the base plate). Depending on the severity of the degradation, the temperature increase may cause the mechanical integrity of the base plate (usually made of plastic) to be compromised (this may occur at approximately 200°C). For example, the base plate may begin to melt, deform, or suffer other structural damage.

[0007] In known arrangements, temperature monitoring or sensing devices are integrated into the meter electronics for monitoring overheating of the meter. However, the meter electronics are typically separated from the contact points between the jaws of the meter mounting device and the meter blade by a plurality of thermal barriers and covers (e.g., a base plate body and a base plate cover). Thus, known arrangements are generally not very effective for early detection of overheating and are primarily used to manage the operating temperature(s) of the meter electronics.

[0008] Other known arrangements may integrate RF arc detectors to detect overheating of the meter. Although a promising solution, using RF arc detection methods requires separate electronic components that may be expensive to integrate.

[0009] There exists a need to provide an improved electrical meter capable of early detection of adverse thermal events at the connection between the blades of the base plate and the jaws of the meter mounting device. Summary of the invention

[0010] According to the present invention in a first aspect, there is provided an electric meter for connecting to a utility power line and a load via a meter placement device and for determining electric power consumption between the utility power line and the load, the electric meter comprising: a base plate, the base plate comprising at least one blade, the at least one blade being configured to couple with a corresponding jaw of the meter placement device to electrically connect the electric meter to the utility power line and the load; a service switch, the service switch being operable to enable or disable the electrical connection between the utility power line and the electric meter, wherein the base plate further comprises a thermal device, the thermal device being located near the at least one blade and being configured to control the service switch to disable the electrical connection between the utility power line and the electric meter if the temperature of the thermal device exceeds a temperature threshold.

[0011] Optionally, the thermal device is positioned to the base plate.

[0012] Optionally, the electric meter further comprises a baseplate cover connected to the baseplate, and wherein the thermal device is located in an internal chamber formed between the baseplate and the baseplate cover.

[0013] Optionally, a service switch is located in the interior chamber.

[0014] Optionally, the electric meter further comprises an electrical conductor, wherein the at least one blade extends from the electrical conductor, and the thermal device is located adjacent to the electrical conductor. Optionally, the thermal device is in close proximity to the electrical conductor.

[0015] Optionally, the electrical conductor is located within the interior chamber and wherein at least one of the blades is located outside of the interior chamber.

[0016] Optionally, the thermal device forms part of an electrical circuit, and wherein the thermal device is configured to disconnect the electrical circuit when a temperature of the thermal device exceeds a temperature threshold.

[0017] Optionally, the service switch is controlled to enable electrical connection between the utility power line and the electric meter when the circuit is closed, and to disable electrical connection between the utility power line and the electric meter when the circuit is broken.

[0018] Optionally, the meter further comprises meter electronics, the meter electronics comprising a microprocessor, and wherein the thermal device forms an electrical circuit with the microprocessor.

[0019] Optionally, if the circuit between the microprocessor and the thermal device is severed, the microprocessor is configured to control a service switch to disable the electrical connection between the utility power line and the electric meter.

[0020] Optionally, the meter electronics are separated from the thermal device by a baseplate cover.

[0021] Optionally, the thermal device forms an electrical circuit with a service switch, and wherein the service switch is configured to disable electrical connection between the utility power line and the electric meter if the electrical circuit is severed.

[0022] Optionally, the base plate includes a first blade and a second blade, a first thermal device located near the first blade, and a second thermal device located near the second blade.

[0023] Optionally, the first thermal device and the second thermal device are positioned on a base plate.

[0024] Optionally, the thermal device comprises a thermal cutoff fuse or a thermal switch.

[0025] According to the present invention in another aspect, a backplane for an electric meter is provided, the electric meter being used to connect to a utility power line and a load via a meter placement device and to determine power consumption between the utility power line and the load, the backplane comprising: at least one blade, the at least one blade being configured to couple with a corresponding jaw of the meter placement device to electrically connect the electric meter to the utility power line and the load; and a thermal device, the thermal device being located near the at least one blade and being configured to control a service switch to disable the electrical connection between the utility power line and the electric meter if a temperature of the thermal device exceeds a temperature threshold.

[0026] Optionally, the base plate also includes a service switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 An exploded view of an exemplary electricity meter is shown;

[0028] Figure 2 An exploded view of an exemplary floor panel and floor cover is shown;

[0029] Figure 3 shows a front view of an exemplary base plate;

[0030] Figure 4 is a schematic block diagram of an exemplary electricity meter. DETAILED DESCRIPTION

[0031] The present invention generally discloses an electric meter for connecting to a utility power line and a load via a meter placement device. The electric meter includes a base plate, the base plate including at least one blade configured to be connected to a utility power line clamp (connected to a utility power line) or a load clamp (connected to a load) of the meter placement device to electrically connect the electric meter to the utility power line or the load. The electric meter also includes a service switch, which can be closed or opened to enable or disable the electrical connection between the electric meter and the utility power line, respectively. An exemplary base plate of the present invention also includes a thermal device, the thermal device is located near and / or adjacent to at least one blade. The thermal device is configured to control the service switch to open to disable the electrical connection between the utility power line and the electric meter if the temperature of the thermal device exceeds a temperature threshold.

[0032] The thermal device of the exemplary electric meter disclosed herein forms part of a base plate arrangement, and in a particular example, is disposed to a base plate body of the base plate. The base plate body may be connected to a base plate cover to form an internal chamber therebetween, and the thermal device is located within the internal chamber. Thus, the thermal device of the present invention is not thermally isolated from the contact point between at least one blade and the jaw by a plurality of internal barriers and covers, as is typical in known arrangements. Specifically, the thermal device is not separated from the contact point between at least one blade and the jaw by the base plate cover.

[0033] By positioning the thermal device on the baseplate, in close proximity to at least one blade, the thermal device experiences temperatures similar to those experienced by the at least one blade and / or the baseplate body. Increased temperatures at the blades and / or baseplate body may thus be detected more quickly, and corrective action (e.g., disabling the supply of power to the meter from the utility power line) may be taken before catastrophic damage to the baseplate and / or other components of the meter occurs due to overheating.

[0034] Figure 1 An exploded view of an exemplary electric meter 100 is shown. The exemplary electric meter 100 is configured to connect to a utility power line and a load via a meter mounting device (not shown). The electric meter 100 includes a base plate 102. The exemplary electric meter 100 also includes a base plate cover 104, a meter electronics 106, an electronics housing 108, and a meter housing 110.

[0035] Figure 2 An exploded view of the base plate 102 and the base plate cover 104 is shown. The base plate 102 includes a base plate body 112, which can be formed entirely or at least partially of plastic. The base plate 102 and the base plate cover 104 are connectable to form an interior chamber between the base plate body 112 and the base plate cover 104.

[0036] The base plate 102 includes blades 114a-114d. The base plate 102 may also include a current coil arrangement including electrical conductors 116a-116d. The electrical conductors 116a-116d are configured to carry current between the blades. Figure 2 In the exemplary arrangement shown, each blade 114a-114d is integrally formed with its respective electrical conductor 116a-116d.

[0037] exist Figure 2 In the exemplary arrangement shown, the conductor 116a is electrically coupled to the conductor 116c (e.g., via the intermediate member 117), so that current can flow between the blades 114a and 114c. Similarly, the conductor 116b is electrically coupled to the conductor 116d (e.g., via the intermediate member 117), so that current can flow between the blades 114b and 114d. The skilled person will appreciate that in alternative arrangements, each blade 114a, 114c can be integrally formed with the conductors 116a, 116c (i.e., provided as a single component), and the blades 114b, 114d can be integrally formed with the conductors 116b, 116d (i.e., provided as a single component).

[0038] The blades 114a-114d may extend through respective apertures 120a-120d formed in the chassis body 112 such that the blades 114a-114d are disposed outside of an interior cavity formed between the chassis body 112 and the chassis cover 104. The current carrying portions 116a-116d may be housed within the interior cavity.

[0039] The blades 114a-114d are configured for connection to a meter installation. In use, when the electric meter 100 is connected to the meter installation, the blades 114a-114d are received by the utility power line jaws of the meter installation (connected to the utility power line) and the load jaws of the meter installation (connected to the load). Figure 2 In the exemplary arrangement shown, the base plate 102 includes four blades. Two blades 114a, 114b are connected to the corresponding utility power line jaws of the meter mounting device, and two blades 114c, 114d are connected to the corresponding load jaws of the meter mounting device.

[0040] The connection between blades 114a-114d and the utility power line jaws and the load jaws causes electrical energy to flow from the utility power line and to the load via the utility power line jaws, the blades received by the utility power line jaws, the electrical conductors, the blades received by the load jaws, and the load jaws. For example, blade 114a may be received by the utility power line jaws of the meter placement device, and blade 114c may be received by the load jaws of the meter placement device. In this example, electrical energy flows from the utility power line to the load via the utility power line jaws, blade 114a, electrical conductors 116a and 116c, blade 114c, and the load jaws. Similarly, blade 114b may be received by a utility power line jaw of a meter placement device, and blade 114d may be received by a load jaw of the meter placement device, such that electrical energy flows from the utility power line and to the load via the utility power line jaw, blade 114b, conductors 116b and 116d, blade 114d, and the load jaw.

[0041] exist Figure 1 and Figure 2 The example electricity meter 100 shown in FIG. 1 is for connection to a typical ANSI 2S meter installation. The skilled person will appreciate that alternative electricity meters may be used to connect to different meter installations and may include, for example, a different number and / or arrangement of blades.

[0042] Figure 3 A plan view of an exemplary base plate 102 is shown. Figure 3 It can be seen that the base plate 102 includes thermal devices 126a, 126b. The thermal devices 126a, 126b are arranged on the base plate 102. Figure 3 In the particular example shown, the thermal devices 126a, 126b are disposed to the base plate body 112. The thermal devices 126a, 126b may be disposed, for example, in corresponding cavities formed in the base plate body 112, although the skilled person will appreciate that there are alternative ways to allow the thermal devices 126a, 126b to be disposed to the base plate 102. The thermal devices 126a, 126b are electrically isolated from the utility service. For example, the thermal devices 126a, 126b may be disposed in corresponding non-conductive cavities. The skilled person will be familiar with alternative methods of electrically isolating components.

[0043] The thermal devices 126 a , 126 b may be positioned within the base plate 102 such that the thermal devices 126 a , 126 b are located within an interior cavity formed between the base plate body 112 and the base plate cover 104 when the base plate 102 is coupled to the base plate cover 104 .

[0044] Thermal devices 126a, 126b are positioned adjacent to each blade 114a, 114b. Figure 3In the exemplary arrangement shown, thermal device 126a is positioned so that it is located near blade 114a, and thermal device 126b is positioned so that it is located near blade 114b. A skilled person will appreciate that alternative arrangements may include a different number of thermal devices, for example, alternative arrangements may include a single thermal device, or more than two thermal devices. In addition, the thermal device(s) may be located Figure 3 An alternative blade to the blade described in .

[0045] As described above, at least a portion of the blades 114a, 114b (and in the example arrangement, substantially all of the blades 114a, 114b) extend through respective holes 120a, 120b in the base plate body 112 such that the blades 114a, 114b are located outside of the interior chamber. In addition, the blades 114a, 114b extend from the electrical conductors 116a, 116b located within the interior chamber. Figure 3 In an exemplary arrangement, the thermal device 126a, 126b may be positioned proximate to the electrical conductor 116a, 116b located in the interior chamber and from which the respective blade 114a, 114b extends. In an exemplary arrangement, there may be no other components between the electrical conductor 116a, 116b and the thermal device 126a, 126b, and in a further exemplary arrangement, the thermal device 126a, 126b may be in close proximity to at least a portion of the electrical conductor 116a, 116b from which the respective blade 114a, 114b extends. Because the blades 114a, 114b and the electrical conductor 116a, 116b are good thermal conductors, the temperature of the electrical conductor 116a, 116b will be substantially the same as the temperature of the blade 114a, 114b (which is in contact with the jaws of the meter placement device).

[0046] Thus, the thermal devices 126a, 126b are not separated from the blades 114a, 114b or the chassis body 112 by the chassis cover 104, and therefore, the overall thermal impedance between the jaw / blade connection and the thermal devices 126a, 126b is reduced. The thermal devices 126a, 126b therefore experience similar temperatures as the chassis 102 and blades 114a, 114b.

[0047] exist Figure 3 In the exemplary arrangement shown, the thermal devices 126a, 126b include thermal cutoff fuses. The thermal cutoff fuses form an electrical circuit with another component of the electric meter 100 and are configured to cut off (or open) the circuit when the temperature of one or both thermal cutoff fuses exceeds a temperature threshold. Exemplary thermal cutoff fuses may be those provided by Cantherm.

[0048] Each thermal cutoff fuse includes a body 134a, 134b including a thermal element located therein. In an exemplary arrangement, the body 134a, 134b of the thermal cutoff fuse is disposed adjacent to each blade 114a, 114b and is disposed adjacent to each blade 114a, 114b. Figure 3 In the particular example shown, the body 134a, 134b is disposed adjacent to the electrical conductor 116a, 116b from which the respective blades 114a, 114b extend. The thermal element is configured to melt when it reaches a temperature threshold, thereby breaking the circuit. The thermal cutoff fuse may be a single use. The skilled person will be familiar with the operation of the thermal cutoff fuse, and further details are not provided here.

[0049] The skilled person will appreciate that in alternative arrangements, alternative thermal devices may be positioned within the base plate 102 such that they are located within an internal chamber formed between the base plate body 112 and the base plate cover 104. For example, in an alternative arrangement, the thermal device(s) 126a, 126b may include a thermal cutoff switch configured to cut (or open) an electrical circuit when a temperature threshold is exceeded and to reclose the electrical circuit when the temperature drops below the threshold temperature. In yet another alternative arrangement, the thermal device(s) may include a temperature sensor configured to collect data indicative of the blade temperature and send the data to the meter electronics 106 for processing and determining whether the temperature threshold has been exceeded. The skilled person will be able to envision other arrangements.

[0050] like Figure 4 As shown in FIG. 1(A) , the electric meter 100 further includes a service switch 140, or a service disconnect actuator / relay. The service switch 140 may be mounted to the base plate 102, and thereby may be housed within an internal chamber formed between the base plate body 112 and the base plate cover 104. When the electric meter 100 is connected to the electric meter mounting device, the service switch 140 is configured to enable electrical connection between the utility power line and the electric meter 100 when closed, and to disable electrical connection between the utility power line and the electric meter 100 when open. The service switch 140 may be controlled by the thermal devices 126a, 126b via the electric meter electronics 106, and in particular, the microprocessor 142 of the electric meter electronics 106.

[0051] The meter electronics 106 may be configured to determine the power consumption between the utility power line and the load. In addition to the microprocessor 142, the meter electronics 106 may also include one or more of the following: a metering circuit / signal conditioning module 144, an AMR interface 146, an LCD or other display 148, and an optional RF interference detector 150. Unlike the thermal devices 126a, 126b described above, which are disposed in an internal cavity formed between the base plate 102 and the base plate cover 104, the meter electronics 106 may be disposed within the electronics housing 108. Thus, the meter electronics 106 may be separated from the base plate 102 by the base plate cover 104.

[0052] like Figure 4 As shown, thermal devices 126a, 126b are electrically connected to meter electronics 106, and in particular microprocessor 142. Figures 1 to 4 In the exemplary arrangement shown, the thermal devices 126 a , 126 b form an electrical circuit with the microprocessor 142 of the meter electronics 106 .

[0053] like Figure 3 As shown, thermal devices 126a, 126b (comprising thermal cutoff fuses in this particular example) are electrically connected in series via leads / wires 160a-160c. Figure 3 In the exemplary arrangement of FIG. 1 , leads 160 a, 160 b terminate at connector 162, which is configured for electrical connection to meter electronics 106, and in particular microprocessor 142. Thermal devices 126 a, 126 b may be connected to microprocessor 142 via a pull-up resistor connected to V3P3 (3.3 VDC DC power supply). A skilled person will appreciate that this connection is merely exemplary, and other ways in which thermal devices 126 a, 126 b may be connected to microprocessor 142 are envisioned. Microprocessor 142 is electrically connected to and in communication with service switch 140.

[0054] In an alternative arrangement, the thermal devices 126a, 126b may be directly connected to the service switch 140. That is, the thermal devices 126a, 126b may form a circuit with the service switch 140 instead of the microprocessor 142, such as Figure 4 The dashed lines between the medium heat devices 126a, 126b and the service switch 140 are shown.

[0055] References below Figure 1-Figure 4 The use of the electrical meter 100 is described to provide early detection of adverse thermal events at the baseplate 102 .

[0056] In use, the electric meter 100 is connected to the utility power line of the residence / building and the load via the meter placement device. The electric meter 100 is placed on the meter placement device by engaging the blades 114a-114d of the base plate 102 with the corresponding jaws of the meter placement device. Due to the connection between the blades 114a-114d of the base plate 102 and the jaws of the meter placement device, electric energy flows from the utility power line to the load via the electric meter 100 as described above.

[0057] In one exemplary arrangement, the thermal devices 126a, 126b include thermal cutoff fuses that form an electrical circuit with the microprocessor 142. During operation of the electric meter 100, if the circuit formed between the thermal cutoff fuses and the microprocessor 142 is closed, the microprocessor 142 is configured to control the service switch 140 to operate in a closed position such that an electrical connection is enabled between the utility power line and the electric meter 100. When the service switch 140 is in the closed position, electrical energy flows from the utility power line through the electric meter and to the load.

[0058] If the temperature of the thermal cutoff fuse, in particular the temperature of the thermal element inside the thermal cutoff fuse, does not exceed the temperature threshold, the circuit formed by the thermal cutoff fuse and the microprocessor 142 remains closed.

[0059] The skilled person will appreciate that the temperature of the thermal cutoff fuse is indicative of the temperature of the base plate 102 and / or the blades 114a, 114b. Thus, the temperature threshold of the thermal device 126a, 126b (in this example, the thermal cutoff fuse) may be selected to be below a temperature at which irreversible damage may occur to the base plate 102 or other components of the electric meter 100. For example, the base plate body 112 is typically formed of a plastic material, which in a specific example may be a polycarbonate resin, such as LEXAN®, which may have a melting point of approximately 150°C. TM 500R. In this specific example, the temperature threshold may be one or more of: substantially 110°C, substantially 120°C, substantially 130°C, and substantially 140°C. The skilled person will appreciate that the base plate may be formed of alternative materials including alternative melting points, and the temperature threshold may be selected accordingly. As long as the temperature of the thermal devices 126a, 126b remains below the temperature threshold, the circuit formed between the microprocessor 142 and the thermal cutoff fuse remains closed, and the service switch 140 remains in the closed position.

[0060] During the life of the electric meter 100 and the meter placement device, the jaws of the meter placement device and / or the blades 114a-114d of the electric meter 100 may degrade. For example, due to exposure to adverse weather conditions, or due to repeated connection and disconnection of the blades 114a-114d of the electric meter 100 to the jaws of the meter placement device. Due to such degradation, resistance may be introduced at the connection between the blades 114a-d and the jaws, and the temperature of the connection may begin to increase.

[0061] As the temperature of the connection between the blades 114a-114d and the jaws increases, the temperature of the thermal cutoff fuse also increases. Because the thermal cutoff fuse is in close proximity to the blades 114a, 114b, the temperature increase experienced by the blades 114a, 114b is converted to a temperature increase of the thermal cutoff fuse with minimal delay due to the thermal cutoff fuse being positioned in the base plate 102 and in proximity to the blades 114a, 114b. The temperature increase of the thermal cutoff fuse occurs with minimal delay because the thermal cutoff fuse is not physically separated from the connection between the blades 114a-114d and the jaws by multiple covers (including the base plate cover 104).

[0062] If the temperature at the blade / jaw junction increases such that the temperature of one or both thermal cutoff fuses exceeds a threshold temperature, the circuit formed between the thermal cutoff fuses and the microprocessor 142 is severed.

[0063] Microprocessor 142 is configured to control service switch 140 to disable the electrical connection between the utility power line and electric meter 100 if the circuit formed between the thermal cutoff fuse and microprocessor 142 is broken. Thus, all service loads from the utility power line are removed from electric meter 100 and the meter installation.

[0064] As described above, because the temperature thresholds of thermal devices 126a, 126b are set below the temperature at which irreversible damage may occur to baseplate 102 or other components of electric meter 100, the thermal cutoff fuses can disconnect the circuit and the service load from the utility power line can be removed before irreversible structural damage occurs. Therefore, in the event of an adverse temperature event, the only component of electric meter 100 that needs to be replaced is the thermal cutoff fuses, and not the entire baseplate.

[0065] The microprocessor 142 may also be configured to control the transmitter of the electric meter 100 to send an alarm signal if the circuit formed by the thermal cutoff fuse is broken. The alarm signal may be sent to a utility control center to indicate, for example, that an adverse temperature event has occurred and that a service visit to the electric meter 100 and the site where the meter is installed is required.

[0066] The above operation is described with reference to the electric meter 100 including the thermal device 126a, 126b including a thermal cutoff fuse. The skilled person will appreciate that in an alternative arrangement, the thermal device 126a, 126b may include a thermal cutoff switch that operates similarly to the thermal cutoff fuse described above, but is configured to reclose the circuit once the temperature of the thermal element therein falls below a threshold temperature. In a further alternative arrangement, the thermal device 126a, 126b may include a temperature sensor disposed proximate the blade and configured to send temperature data to the microprocessor 142. The microprocessor 142 may be configured to disable the electrical connection between the utility power line and the electric meter 100 if the received temperature data indicates that the temperature at the temperature sensor exceeds a threshold value. The skilled person will appreciate that alternative temperature or heat devices may also be used.

[0067] Those skilled in the art will appreciate that various modifications may be made to the embodiments described above without departing from the scope of the present invention.

Claims

1. An electric meter for connecting to a utility power line and a load via a meter placement device and for determining electric power consumption between the utility power line and the load, the electric meter comprising: a base plate including at least one blade configured to couple with a corresponding jaw of the meter placement device to electrically connect the electric meter to the utility power line and the load; a service switch operable to enable or disable the electrical connection between the utility power line and the electric meter, The backplane further includes a thermal device located proximate to the at least one blade and configured to control the service switch to disable the electrical connection between the utility power line and the electric meter if a temperature of the thermal device exceeds a temperature threshold.

2. The electric meter of claim 1, wherein the thermal device is mounted to the base plate.

3. The electric meter of claim 1 or 2, further comprising a baseplate cover connected to the baseplate, and wherein the thermal device is located in an internal cavity formed between the baseplate and the baseplate cover.

4. The electric meter of claim 3, wherein the service switch is located in the interior chamber.

5. An electric meter according to any preceding claim, further comprising an electrical conductor, wherein the at least one blade extends from the electrical conductor, and wherein the thermal device is located adjacent the electrical conductor.

6. An electric meter according to claim 5, when dependent on claim 3 or 4, wherein the electrical conductor is located in the internal chamber, and wherein the at least one blade is located outside the internal chamber.

7. An electric meter according to any preceding claim, wherein the thermal device forms part of an electrical circuit, and wherein the thermal device is configured to disconnect the electrical circuit when the temperature of the thermal device exceeds a temperature threshold.

8. The electric meter of claim 7, wherein the service switch is controlled to enable the electrical connection between the utility power line and the electric meter when the circuit is closed, and to disable the electrical connection between the utility power line and the electric meter when the circuit is broken.

9. An electricity meter according to claim 7 or 8, further comprising meter electronics including a microprocessor, and wherein the thermal device forms the circuit with the microprocessor.

10. The electric meter of claim 9, wherein if the circuit between the microprocessor and the thermal device is severed, the microprocessor is configured to control the service switch to disable the electrical connection between the utility power line and the electric meter.

11. An electricity meter as claimed in claim 9 or 10 when dependent on claim 3, wherein the meter electronics are separated from the thermal device by the baseplate cover.

12. The electric meter of claim 7 or 8, wherein the thermal device forms an electrical circuit with the service switch, and wherein the service switch is configured to disable the electrical connection between the utility power line and the electric meter if the electrical circuit is severed.

13. An electric meter according to any preceding claim, wherein the base plate comprises a first blade and a second blade, a first thermal device located adjacent the first blade and a second thermal device located adjacent the second blade.

14. The electric meter of claim 13, wherein the first thermal device and the second thermal device are mounted to the base plate.

15. An electricity meter as claimed in any preceding claim, wherein the thermal device comprises a thermal cut-off fuse or a thermal switch.

16. A backplane for an electric meter for connecting to a utility power line and a load via a meter mounting device and for determining electric power consumption between the utility power line and the load, the backplane comprising: at least one blade configured to couple with a corresponding jaw of the meter placement device to electrically connect the electric meter to the utility power line and the load; as well as A thermal device is located proximate to the at least one blade and is configured to control a service switch to disable the electrical connection between the utility power line and the electric meter if a temperature of the thermal device exceeds a temperature threshold.

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