GB2554913A

GB2554913A - Sensor apparatus for sending overheating

Info

Publication number: GB2554913A
Application number: GB1617411.2A
Authority: GB
Inventors: John Fletcher Adam; Elaine Christine Heathcote
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-10-13
Filing date: 2016-10-13
Publication date: 2018-04-18
Also published as: GB2554959A; WO2018069720A1; GB201700506D0; GB201617411D0

Abstract

A sensor apparatus for sensing overheating comprises a plurality of heat sensing modules, that each comprise a thermal switch 32 connected between a first terminal 33 and a second terminal 34; and are electrically connected to each other. The heat sensing modules may be mounted near electrical components such as a busbar, neutral bar, mains switch and line connections for a fuse, MCB, RCD or RCBO in a distribution board or consumer unit. First terminals 33 may be connected together on a common line, or earth line, and second terminals 34 may be connected together, asserting a fault signal if any of the thermal switches is activated, or to respective signals lines or to an isolation device disconnecting power to the device being monitored. Modules may be grouped and connected to respective mains switches. Each module may comprise a housing and a pair of tracks forming the terminals. The thermal switch may be mounted on a printed circuit board. Connections may be by jumper wires or ribbon cable to which the modules may be electrically and mechanically connected using spaced connectors. Each module can comprise two thermal switches that are isolated from each other.

Description

(54) Title of the Invention: Sensor apparatus for sending overheating Abstract Title: Sensing overheating of electrical components (57) A sensor apparatus for sensing overheating comprises a plurality of heat sensing modules, that each comprise a thermal switch 32 connected between a first terminal 33 and a second terminal 34; and are electrically connected to each other. The heat sensing modules may be mounted near electrical components such as a busbar, neutral bar, mains switch and line connections for a fuse, MCB, RCD or RCBO in a distribution board or consumer unit. First terminals 33 may be connected together on a common line, or earth line, and second terminals 34 may be connected together, asserting a fault signal if any of the thermal switches is activated, or to respective signals lines or to an isolation device disconnecting power to the device being monitored. Modules may be grouped and connected to respective mains switches. Each module may comprise a housing and a pair of tracks forming the terminals. The thermal switch may be mounted on a printed circuit board. Connections may be by jumper wires or ribbon cable to which the modules may be electrically and mechanically connected using spaced connectors. Each module can comprise two thermal switches that are isolated from each other.

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Sensor Apparatus for Sensing Overheating

Technical Field

The present invention relates to a sensor apparatus for sensing overheating, for example overheating of electrical circuits, connectors (for example connections and terminals) and components.

Background

Overheating of electrical components may arise due to various problems leading to poor electrical connectivity. Such problems may arise due to incorrectly tightened screws, loose wires, corrosion, mechanical fatigue and the like. These problems may cause overheating and consequently electrical fires. In WO266/125996, it was proposed to use a thermal switch to detect such occurrences of overheating. In WO2014/006356, an implementation of such a sensing apparatus was proposed in which an array of thermal switches in a carriage was provided, making installation of the sensor apparatus more straightforward than installation of multiple discrete sensors. However, this solution resulted in installation difficulties if the components to be monitored were not arranged perfectly linearly, and a lack of flexibility of installation. It will be appreciated that overheating can also be experienced in other contexts, such as in the case of a fire.

The present invention is intended to address certain of these limitations.

Summary of the Invention

According to the present invention, there is provided a sensor apparatus for sensing overheating, the apparatus comprising a plurality of heat sensing modules, each heat sensing module comprising a thermal switch connected between a first terminal and a second terminal, wherein the plurality of heat sensing modules are electrically connected to each other. Preferably, the heat sensing modules are for mounting at or near a plurality of electrical components. By providing the sensor apparatus in modular form with the modules being electrically connected together, flexible installation of the individual heat sensors (thermal switches) can be achieved (because the modules can be individually placed on, against or proximate the electrical components they are intended to monitor), while electrically the separate modules can be treated as a group, reducing wiring requirements compared with an arrangement in which completely separate sensors are utilised.

As a result of the modular design, the sensing apparatus is more wholesaler friendly, since one type of item (module) can be stocked, and combined with other modules to achieve specific requirements, rather than providing multiple different sensors of different shapes and geometries. Further, the modular system is inexpensive and of a 'fit-all' nature, making it easier and space saving for engineers to hold stock in their van. Due to its flexible nature, it can be fitted to many more applications within or external to a consumer unit or distribution board. In other words, the sensor apparatus may be used (for example) for monitoring overheating of other electrical components, or even overheating outside of the context of electrical components (for example fire detection). Also, each module can be individually suited to service the requirement of each detection point instead of a single common/shared actuation result system. Further, detection may not be required at all points within (for example) a distrubtion box, and the modular design allows for a detection point omission where detectin is deemed unnecessary.

In one embodiment, the first terminals of the plurality of modules are electrically connected together on a common line. This embodiment may be implemented in a form in which the second terminals of the plurality of modules are electrically connected together on a common signal line, a fault notification signal being asserted on the common signal line if the thermal switch of any of the modules is activated. This effectively provides a notification externally that there is a fault detected by one or more of the modules (without identifying which). Alternatively, this embodiment may be implemented in a form in which the second terminals of the plurality of modules are electrically connected to respective different signal lines, a fault notification signal being asserted on a signal line if the thermal switch of the module electrically connected to that signal line is activated. This effectively provides a notification externally of which of the modules is detecting overheating.

In another embodiment, the first terminals of the plurality of modules are electrically connected together on an earth line. In one implementation of this embodiment, the second terminals are electrically connected together and to a mains switch for disconnecting the power to the plurality of electrical components if the thermal switch of any of the modules is activated. This effectively trips the power to all of the electrical components being monitored (for example an entire distribution board) if a fault is detected by one or more of the modules (that is, if a thermal switch activates) . In an alternative implementation of this embodiment, the second terminals of a first group of the modules are connected together and to a first mains switch for disconnecting the power to the electrical components being monitored by the first group of modules if the thermal switch of any of the modules of the first group is activated, and the second terminals of a second group of the modules are connected together and to a second mains switch for disconnecting the power to the electrical components being monitored by the second group of modules if the thermal switch of any of the modules of the second group is activated. This implementation, intended for handling a split load distribution board, effectively trips the power to a subset of the electrical components being monitored (for example half of a split load distribution board) if a fault is detected by one or more of the modules monitoring that subset. In yet another implementation of this embodiment, the second terminal of each module is electrically connected to an isolation device (for example an RCBO or similar device) for disconnecting the power to the electrical component being monitored by that module if the thermal switch of that module is activated.

This embodiment effectively trips the power to only the electrical component being monitored by the module if a fault is detected by that module.

The electrical components being monitored may comprise one or more of a neutral bar, common feeder busbar, mains switch and line connections for fuses, MCB’s, RCD’s and RCBO’s in a distribution board or consumer unit. It will further be appreciated that non-electrical components could be monitored, or the modules instead provide to detect overheating in selected areas rather than of particular components.

Each module may comprise a housing containing the thermal switch and a pair of metal tracks which form the first and second terminals, the thermal switch being mounted between the pair of metal tracks, activation of the thermal switch enabling electric current to flow across the thermal switch and between the first and second terminals.

Alternatively, each module may comprise a printed circuit board bearing mounting pins or plug and/or socket components forming the first and second terminals, the thermal switch being mounted to the printed circuit board.

The electrical connections between the modules may be made using individual jumper wires and/or a loom of jumper wires and/or flex circuits such as (but not limited to) polyimide circuits. Alternatively, the modules may be mounted onto a ribbon cable. In some cases, both a ribbon cable and jumper wires/loom may be used. For example, the electrical connections relating to notification may be achieved using a ribbon, while those relating to isolation may be achieved using jumper cables.

In the case that a ribbon cable is used, this may comprise a plurality of plug or socket connectors distributed along its length, via which the modules can be electrically and mechanically connected to the ribbon cable.

In some embodiments, the modules are physically mounted on the electrical components which they are intended to monitor.

It will be appreciated that both the notification function and the isolation function could be achieved by a single module. For example, the module may comprise two thermal switches, the first and second terminals of the notification function being connected to one of the two thermal switches and the first and second terminals of the isolation function being connected to the other of the two thermal switches. The two thermal switches and their associated terminals are preferably electrically isolated from each other.

It will be appreciated that each terminal of each module may comprise one or more terminal connectors for connecting that terminal to a terminal of another connector or externally of the sensor apparatus.

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 schematically illustrates a distribution box containing electrical components and sensor modules;

Figures 2A and 2B schematically illustrate the wiring of sensor modules for fault notification;

Figures 3A and 3B schematically illustrate the wiring of sensor modules for isolation; Figure 4 schematically illustrates combined wiring for providing both fault notification and isolation;

Figure 5 schematically illustrates a sensor module; and

Figures 6A and 6B schematically illustrate a ribbon based system.

Detailed Description

Referring to Figure 1, an electrical distribution box I consumer unit 1 is shown. The unit 1 comprises a number of electrical components 2 in the areas of a neutral bar 2a, phase/line 2b and bus bar 2c. The electrical components 2 may include (by way of non-limiting example) the neutral bar, common feeder bus bar, mains switch and line connections for fuses, MCBs (miniature circuit breakers), RCDs (residual current devices) and RCBOs (residual current breaker with overcurrent). Heat sensing modules 3 are provided at, on, adjacent or near various of the components 2. The heat sensing modules 3 may for example be mounted on the electrical components 2 by way of clips or similar. It will be appreciated that, for larger electrical components 2, multiple heat sensing modules 3 may be mounted on a single electrical component. The heat sensing modules 3 are electrically connected together in a chain by electrical connections 4, which may take the form of jumper cables/leads or a ribbon cable for example. A lead-in/out cable 5 is connected to the first heat sensing module 3 in the chain to carry an electrical signal from the chain of heat sensing modules 3 to a junction box (not shown) or other third party device (not shown) which will process the electrical signal, for example to display to a user an indication that overheating has been detected in the distribution box I consumer unit

1. The heat sensing units 3 each contain a thermal switch, usually in an open state, which switches to a closed state if the local temperature at the thermal switch exceeds a predetermined temperature, thereby permitting an electrical current to flow through the thermal switch. This flow of electrical current may serve as a notification of overheating, or may directly trip out electrical components as will be described subsequently. Various thermal switches may be used, such as the one described in W02006/125996 and implemented in WO2014/006356. In use, if one of the electrical components 2 overheats, the thermal switch of an adjacent heat sensing module 3 will be activated, closing the switch and permitting an electrical current to pass through it, causing an electrical signal to be transmitted through the lead in/out cable 5 and to an external device. The external device may then activate an alarm or display a visual indication of overheating. The thermal switches may work by monitoring (and reacting to) the local ambient (air) temperature, in which case they need only be located in the vicinity of the component being monitored, rather than being in direct physical contact.

Referring to Figure 2A, an example of how a chain of heat sensing modules 3 can be provided in a chain is shown, with wiring utilised for providing a notification of overheating. Each of the heat sensing modules 3 can be seen to comprise a thermal switch 32 which is mounted between a first terminal 34 and a second terminal 33. When the thermal switch 32 is activated due to the local temperature rising above a predetermined level, electrical current is permitted to pass between the first and second terminals 34, 33. Each of the terminals may take the form of an electric track on a printed circuit board (PCB) or an electrical contact. In either case, terminal connectors 37 (e.g. a pin, plug or other element to which a connection can be made) may be provided, for example as shown here at either end of the terminals 34, 33.

As can be seen in Figure 2A, the first terminal 34 of each module 3 is electrically connected to a common line 36. In particular, the modules 3 are daisy chained together, with the common line 36 being formed from the first terminals 34 of each module 3, and the electrical connections between the terminals 34 (made via the terminal connectors 37). Similarly, the second terminals 33 of the modules 3 are electrically connected together on a common signal line 35. Again, the modules 3 are daisy chained together, with the common signal line 35 being formed from the second terminals 33 of each module 3, and the electrical connections between the terminals 33 (made via the terminal connectors 37). In the event of the temperature rising high enough to activate one of the thermal switches 32, the activated thermal switch will close, thereby permitting an electric current to flow across it. This will permit the current to flow between the first and second terminals 34, 33 of the activated module, and thus between the common line 36 and the common signal line 35. This will be the case irrespective of which of the modules is activated. In this way, a fault notification signal is asserted on the common signal line if the thermal switch of any of the modules is activated.

Referring now to Figure 2B, an alternative arrangement of Figure 2A is provided in which individual notification is provided of exactly which of the heat sensing modules 3 has been activated due to local overheating. Like reference numerals have been used for parts which correspond between Figures 2A and 2B. Such parts have the same structure and function, and will not be repeated in the interests of brevity. The difference between the arrangement of Figures 2A and 2B is that in Figure 2B the second terminals 33 of the modules 3 are electrically connected to respective different signal lines 35a, 35b. As a result, when the thermal switch 32 of a particular module is activated, a fault notification signal is asserted on only that signal line connected to that particular module. It will be appreciated that there is thus an individual signal wire for each module. It will further be appreciated that while two modules are shown in Figures 2A and 2B, any number of modules may be provided.

Referring to Figure 3A, an example of how a chain of heat sensing modules 3’ can be provided in a chain is shown, with wiring utilised for isolating (at least) the overheating electrical components. Each of the heat sensing modules 3’ can be seen to comprise a thermal switch 42 which is mounted between a first terminal 43 and a second terminal 44. When the thermal switch 42 is activated due to the local temperature rising above a predetermined level, electrical current is permitted to pass between the first and second terminals 43, 44. Each of the terminals may take the form of an electric track on a printed circuit board (PCB) or an electrical contact.

In either case, terminal connectors 47 (e.g. a pin, plug or other element to which a connection can be made) may be provided, for example as shown here at either end of the terminals 43, 44. As can be seen in Figure 3A, the first terminal 43 of each module 3’ is electrically connected to an earth line 45. In particular, the modules 3’ are daisy chained together, with the earth line 45 being formed from the first terminals 43 of each module 3’, and the electrical connections between the terminals (made via the terminal connectors 47). Similarly, the second terminals 44 of the modules 3’ are electrically connected together on a line 46, and to a live terminal of a mains switch 49 for disconnecting the power to the electrical components if the thermal switch if any of the modules 3’ is activated. Again, the modules 3’ are daisy chained together on the line 46, with the line 46 being formed from the second terminals 44 of each module 3’, and the electrical connections between the terminals (made via the terminal connectors 47). In the event of the temperature rising high enough to activate one of the thermal switches 42, the activated thermal switch will close, thereby permitting an electric current to flow across it. This will permit the current to flow between the first and second terminals 43, 44 of the activated module, and thus between the earth line 45 and the line 46. This will be the case irrespective of which of the modules is activated. In this way, the mains switch 49 is triggered to trip I disconnected power from the electrical components being monitored by the modules 3’ if the thermal switch of any of the modules is activated. In a variant of this, the modules are provided in two (or more) groups. In this case, the second terminals 44 of a first group of the modules are connected together and to a first mains switch for disconnecting the power to the electrical components being monitored by the first group of modules if the thermal switch of any of the modules of the first group is activated. Similarly, the second terminals 44 of a second group of the modules are connected together and to a second mains switch for disconnecting the power to the electrical components being monitored by the second group of modules if the thermal switch of any of the modules of the second group is activated. In this way, a split load distribution board can be powered down in parts, with only the part subject to overheating being disconnected from its mains supply by the appropriate switch.

Referring now to Figure 3B, an alternative arrangement of Figure 3A is provided in which individual isolation of electrical components is provided, with only an electrical component being detected as overheating being deactivated due to local overheating. Like reference numerals have been used for parts which correspond between Figures 3A and 3B. Such parts have the same structure and function, and will not be repeated in the interests of brevity. The difference between the arrangement of Figures 3A and 3B is that in Figure 3B the second terminals 44 of the modules 3’ are electrically connected to respective different signal lines 46a, 46b, and then to a respective RCBO 48a, 48b. The RCBO receiving a signal on the signal line 46a or 46b deactivates in response to the signal. As a result, when the thermal switch 42 of a particular module is activated, a signal is asserted on only that signal line connected to that particular module. It will be appreciated that there is thus an individual signal wire for each module, which goes to the RCBO being monitored by that module.

While Figures 2A and 2B have been described separately from Figures 3A and 3B, in practice it may be beneficial in some cases for both notification functionality (the Figure 2A/2B arrangement) and isolation functionality (the Figure 3A/3B arrangement) to be provided by a single set of modules. Due to the nature of the wiring required, it is preferable that the module comprise two separate thermal switches, the first and second terminals of Figures 2A and/or 2B being connected to one of the two thermal switches and the first and second terminals of Figures 3A and 3B being connected to the other of the two thermal switches. The two thermal switches and their associated terminals are electrically isolated from each other, in order that they do not disturb each other’s function. Figure 4 shows an array of heat sensing modules 30 which have both notification and isolation functionality. In particular, each of the modules is electrically connected to a common earth line 32, and to individual live signal lines 34, permitting individual isolation ofthe electrical components being monitored (e.g. RCBOs) as explained with reference to Figure 3A. Each of the modules is also electrically connected to a common signal line 36, and to individual notification signal lines 38, permitting notification of a specific heat sending module which has detected overheating. As mentioned above, the lines 32 and 34 (and their respective thermal switches within the modules) are electrically isolated from the lines 36 and 38 (and their respective thermal switches within the modules). The modules 30 are shown adjacent in this case, and may in some examples be mechanically engageable. However, in general the modules are physically and in particular mechanically separate and only electrically connected.

Referring to Figure 5, an example heat sensing module 300 is shown. The module 300 comprises a housing 310 containing a thermal switch 320 (shown in dashed lines to indicate it is located internally of the housing, first and second terminals (not shown) and terminal connectors 332, 334, 336, 338. The terminal connectors 332, 334, 336, 338, which may either be contact pins (if the thermal switch is mounted to a PCB within the housing, in which case the contact pins will be mounted on the PCB and connected to thermal switch 320 via conductive tracks on the PCB), extensions of the first and second terminals (if the thermal switch is simply mounted within the housing and the terminals take the form of metal contacts which are in contact with the two sides of the thermal switch and which extend outside the housing to permit external connection) or plugs (which could either be PCB mounted, or mounted to said metal contacts). For example, in the case of metal contacts, a U shaped contact (not shown) could be used, with the base of the U extending within and along the housing past (and in contact with) the thermal switch, and the upright parts of the U forming the terminal connectors. In Figure 5, the terminal connectors 332 and 334 are electrically connected to one end 320a of the thermal switch by a track or metal contact, while the terminal connectors 336 and 338 are electrically connected to the other end 320b of the thermal switch by a track of metal contact. The module 300 can be electrically connected to other modules, or to external devices (for notification or isolation purposes as explained above) by connecting the terminal connectors 332, 334, 336, 338 using jumper/link cables, wires, looms or other connecting means. The terminal connectors may be replaced with plug/socket connectors if preferred in order to make connections easier, or a crimp could be used to secure a cable onto a terminal connector. It will be appreciated that it is beneficial that two terminal connectors be provided in respect of each terminal so that each module can be easily electrically connected to two other modules (obviously the first and last module in the array will only be connected to one other module). It will be appreciated that the structure of Figure 5 only provides for a single thermal switch and a single pair of terminals, while as explained in relation to Figure 4 two thermal switches and two pairs of terminals would generally be used in order to give effect to notification and isolation functions. If both functions were to be provided, the physical structure of Figure 5 could be duplicated. In such a case a PCB based solution may be beneficial.

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Referring to Figures 6A and 6B, an implementation in which the modules are electrically connected (at least in part) by a ribbon cable is shown. In Figure 6A, a sensor apparatus for use at a neutral bar of a distribution board is shown. The sensor apparatus comprises a first heat sensing module 3000a and a second heat sensing module 3000b. The heat sensing modules 3000a and 3000b may be identical, and as described above. In practice a greater number of modules may be used, but only two are shown here in the interests of simplicity. The modules are electrically connected together via a ribbon cable 3050. In addition, the modules may be mechanically connected to the ribbon cable 3050, in which case the ribbon cable 3050 also serves as a support for the modules. Such a mechanical connection could be achieved by way of adhesives or clip, or alternatively a plug and socket arrangement could be provided whereby (for example) a series of sockets are arranged along the ribbon cable 3050, into which a plug (for example) mounted on the modules can be inserted. In this case, the plug/socket arrangement would provide both an electrical and mechanical connection between the ribbon cable 3050 and the modules 3000, and would also permit easy connection/disconnection of the modules for installation and replacement purposes. If fewer modules are required than the number of plugs or sockets on the ribbon, then certain plugs/sockets on the ribbon could be left without a module (a cap may be required instead). Also connected to the ribbon cable 3050 are plugs 3010 which is provided in order to enable the ribbon of the sensor apparatus to be joined to another ribbon and/or a take on connector which connects via a wire to a junction box or other device where a notification signal from the ribbon cable can be received. The ribbon cable 3050 comprises in this case signal cores (shown with solid lines) which correspond to the lines 35a, 35b in Figure 2B, and a common earth (shown with a dashed line) which corresponds to the line 36 in Figures 2B. It will be appreciated that only two cores are shown here, corresponding to the signal outputs (for notification) from the two modules, but if a greater number of modules are used then a greater number of cores are required for individual notification. The ribbon cable 3050 may bear only some of the electrical connections. For example, the ribbon cable 3050 may bear the signal lines relating to notification, while those relating to isolation (that is, the wiring shown in Figures 3A and 3B) may be achieved by way of separate wires. However, it is also possible for the ribbon cable to carry signals relating to isolation.

Referring to Figure 6B, a further ribbon for connection to the line portion of the distribution box is shown. Here, only two modules 4000a and 4000b are shown for clarity, but in practice a larger number of modules (for example 10) may be provided on the same ribbon 4050. As with Figure 6A, external connections to other ribbons are made via plugs 4010. The structure of the ribbon based assembly of Figure 6B is substantially the same as that of Figure 6A, and thus description thereof will not be repeated here.

Claims

1. A sensor apparatus for sensing overheating, the apparatus comprising a plurality of heat sensing modules, each heat sensing module comprising a thermal switch connected between a first terminal and a second terminal, wherein the plurality of heat sensing modules are electrically connected to each other.

2. A sensor apparatus according to claim 1, wherein the heat sensing modules are for mounting at or near a plurality of electrical components.

3. A sensor apparatus according to claim 1 or claim 2, wherein the first terminals of the plurality of modules are electrically connected together on a common line.

4. A sensor apparatus according to claim 3, wherein the second terminals of the plurality of modules are electrically connected together on a common signal line, a fault notification signal being asserted on the common signal line if the thermal switch of any of the modules is activated.

5. A sensor apparatus according to claim 3, wherein the second terminals of the plurality of modules are electrically connected to respective different signal lines, a fault notification signal being asserted on a signal line if the thermal switch of the module electrically connected to that signal line is activated.

6. A sensor apparatus according to claim 2, wherein the first terminals of the plurality of modules are electrically connected together on an earth line.

7. A sensor apparatus according to claim 6, wherein the second terminals are electrically connected together and to a mains switch for disconnecting the power to the plurality of electrical components if the thermal switch of any of the modules is activated.

8. A sensor apparatus according to claim 6, wherein the second terminals of a first group of the modules are connected together and to a first mains switch for disconnecting the power to the electrical components being monitored by the first group of modules if the thermal switch of any of the modules of the first group is activated, and the second terminals of a second group of the modules are connected together and to a second mains switch for disconnecting the power to the electrical components being monitored by the second group of modules if the thermal switch of any of the modules of the second group is activated.

9. A sensor apparatus according to claim 6, wherein the second terminal of each module is electrically connected to an isolation devicefor disconnecting the power to the electrical component being monitored by that module if the thermal switch of that module is activated.

10. A sensor apparatus according to claim 2, wherein the electrical components being monitored comprise one or more of a neutral bar, common feeder busbar, mains switch and line connections for fuses, MCB’s, RCD’s and RCBO’s in a distribution board or consumer unit.

11 .A sensor apparatus according to any preceding claim, wherein each module comprises a housing containing the thermal switch and a pair of metal tracks which form the first and second terminals, the thermal switch mounted between the pair of metal tracks, activation of the thermal switch enabling electric current to flow across the thermal switch and between the first and second terminals.

12. A sensor apparatus according to any one of claims 1 to 10, wherein each module comprises a printed circuit board bearing mounting pins or plug and/or socket components forming the first and second terminals, the thermal switch being mounted to the printed circuit board.

13. A sensor apparatus according to any preceding claim, wherein the electrical connections between the modules are made using individual jumper wires and/or a loom of jumper wires.

14. A sensor apparatus according to any one of claims 1 to 12, wherein the modules are mounted onto a ribbon cable.

15. A sensor apparatus according to claim 14, wherein the ribbon cable comprises a plurality of plug or socket connectors distributed along its length, via which the modules can be electrically and mechanically connected to the ribbon cable.

16. A sensor apparatus according to claim 2, wherein the modules are physically mounted on the electrical components which they are intended to monitor.

17. A sensor apparatus according to any one of claims 3 to 5 and any one of claims 6 to 9.

18. A sensor apparatus according to claim 17, wherein the module comprises two thermal switches, the first and second terminals of claims 3, 4 or 5 being connected to one of the two thermal switches and the first and second terminals of claims 6, 7, 8 or 9 being connected to the other of the two thermal switches.

19. A sensor apparatus according to claim 18, wherein the two thermal switches and their associated terminals are electrically isolated from each other.

20. A sensor apparatus according to claim 18 or claim 19, wherein each terminal of each module comprise one or more terminal connectors for connecting that terminal to a terminal of another connector or externally of the sensor apparatus.

21 .A sensor apparatus substantially as hereinbefore described with reference to the accompanying drawings.

Intellectual

Property

Office

Application No: GB1617411.2