GB2545460A

GB2545460A - Distribution board

Info

Publication number: GB2545460A
Application number: GB1522279.7A
Authority: GB
Inventors: Alfred Huntley David
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-12-17
Filing date: 2015-12-17
Publication date: 2017-06-21
Anticipated expiration: 2035-12-17
Also published as: GB201522279D0; GB2545460B

Abstract

A distribution board for an electricity supply system distribution board comprises a plurality of ways 20 each connected to an input connection 10 for connection to a supply. A programmable controller 30 receives a measurement of current flowing through each of ways 20 using current sensing device 22 and, for each way, evaluates the measured current against a programmable fault condition and if the fault condition is met triggers a remedial action. The remedial action may use a controllable switch 26 to disconnect the output connection of the way, activate an alarm, send a warning message to a remote device, or record the fault occurrence in memory. The fault condition may comprise a current threshold, a comparison with a measure of current flowing in a neutral conductor using a second current detector 24, and a deviation of current form an expected value. The controller 30 may be programmed by a user interface, and monitor energy consumption of each circuit. The distribution board may be WAN, LAN, or WLAN connected.

Description

DESCRIPTION

DISTRIBUTION BOARD FIELD OF THE INVENTION

This invention relates to a distribution board for an electricity supply system.

BACKGROUND OF THE INVENTION A distribution board - as known as a circuit breaker panel, consumer unit (CU), electrical panel, fuse board, or fuse box - is a component of an electricity supply system that divides electrical power from an input into multiple circuits and typically provides independent protection of some form for each of these circuits. Each circuit may be associated with a specific purpose or class of electrical equipment. For example, one circuit may provide electricity for lighting; another circuit may provide electricity to power sockets; and another may provide electricity to an oven/cooker.

The distribution board therefore comprises a plurality of “ways”. Each circuit is associated with a respective “way”. Each way comprises a live connection and a neutral connection for providing electricity to the circuit. The distribution board also comprises a plurality of protective devices. Typically, each way has at least one protective device associated with it. The distribution board may also comprise additional protective devices which protect all of the ways collectively. Known protective devices include a fuse, a Miniature Circuit Breaker (MCB), a Residual Current Device (RCD), a Residual Current Breaker with Overload protection (RCBO), and an Earth Leakage Circuit Breaker (ELCB). A fuse protects against current overload by providing a component that fails (“blows”) intentionally in response to excess current. An MCB is a modern alternative to a fuse, comprising a switch and a current threshold detector. If the current drawn by the circuit exceeds a fixed threshold, the detector detects this and opens the switch in response, cutting off the flow of current. Unlike a fuse, an MCB is not destroyed by the excess current and can be reset manually (preferably after the fault that caused the excess current has been rectified). In many modern distribution boards, each way (and therefore each circuit) is protected by a respective MCB.

The purpose of an ELCB is to protect against electric shock. It is connected in series with the earth conductor to detect current flowing to earth. Typically this is done by detecting a voltage drop in a coil connected in series with the earth. When current is detected flowing to earth, the ELCB opens a switch, to cut off the electricity supply. A distribution board may have a single ELCB, which may provide earth protection for all of the circuits connected to the distribution board.

An RCD is a modern alternative to an ELCB. It works by detecting an imbalance in the current between live and neutral conductors. When there is no fault, the live current and neutral current are equal. When a fault occurs, and some current returns via ground, the live current and neutral current differ. The RCD detects this and opens a switch in response, cutting off the supply of current. An RCD may be wired to protect an individual circuit (way), or wired to protect multiple circuits (ways) collectively - including, for example protecting all of the ways of the distribution board collectively.

An RCBO combines the functions of an MCB and an RCD.

Each of the protective devices discussed above is typically provided as a single integral module, having a fixed protection threshold. For example, one MCB may be designed for a rated current of 6 A. Another type of MCB may be designed for a rated current of 32 A. The MCB for each way is chosen when commissioning the electricity supply system, according to the current-rating and type of the electrical equipment that will be connected to the corresponding circuit. Commonly-available preferred values for the rated current are 6 A, 10 A, 13 A, 16 A, 20 A, 25 A, 32 A, 40 A, 50 A, 63 A, 80 A, 100 A, and 125 A.

As well as being designed for different rated currents, different types of MCB are designed to open the switch at different levels of instantaneous tripping current. For example, a Type B MCB is designed to break the circuit within 100 ms if the instantaneous current is in the range 3 ln to 5 ln, where ln is the rated current. A Type C MCB is designed to break the circuit within 100 ms if the instantaneous current is in the range 5 l„ to 10 ln. A Type D MCB is designed to break the circuit within 100 ms if the instantaneous current is in the range 10 ln to 20 ln. The different types permit different levels of overcurrent, because different types of electrical equipment may draw large currents transiently even in normal operation - for example, an inrush current or switch-on surge.

SUMMARY OF THE INVENTION

The invention is defined by the claims.

According to one aspect there is provided a distribution board for an electricity supply system, the distribution board comprising: an input connection for coupling to an electrical supply; and a plurality of ways, each way having an input coupled to the input connection of the distribution board and having an output connection for coupling to an electrical circuit, each way comprising first sensing device, configured to sense a current flowing through the way, to generate a first current measurement, the distribution board further comprising a programmable controller configured to, for each way: receive the first current measurement from the first sensing device; evaluate the first current measurement against a programmable fault condition; and if the programmable fault condition is met, trigger a remedial action.

This distribution board can be more versatile than prior distribution boards and can provide additional functionality. Because the fault condition is programmable, the electrical parameters of each way can be customised freely. For example, the programmable fault condition could be programmed to emulate an MCB with any desired tripping current.

Preferably, the programmable controller can be reprogrammed if desired. This can allow the electricity supply system to be modified, updated, or upgraded, without the need to replace the distribution board or its hardware components.

Preferably the distribution board is interactive and optionally provides a user interface, for a (qualified) user or installer to program the programmable controller.

The programmable controller can also be programmed with multiple fault conditions and/or multiple remedial actions. Different remedial actions may be performed in response to different fault conditions and/or multiple remedial actions may be performed in response to a single fault condition.

The remedial action may be programmable or may be predetermined. If programmable, the remedial action may be programmable in the same way as the programmable fault condition.

The sensing device may comprise a current transformer.

Each way optionally comprises an electrically controllable switch for selectively disconnecting the output connection from the input of the way; and the remedial action optionally comprises controlling the electrically operable switch to disconnect the output connection from the input of the way.

Opening the switch can allow the programmable controller to emulate the function of a circuit breaker. The electrically controllable switch may comprise a relay or a power electronic semiconductor device, such as a thyristor, TRIAC, or Silicon Controlled Rectifier (SCR).

The programmable condition may comprise a current threshold.

This can allow the programmable controller to emulate the function of an MCB. However, unlike a conventional MCB, the tripping current can be set at any desired current threshold.

Optionally, in each way: the first sensing device is configured to sense a current flowing in a live conductor of the way, and the way further comprises a second sensing device configured to sense a current flowing in a neutral conductor of the way, to generate a second current measurement.

Providing current sensing devices on both the live and neutral conductors can allow a wider and more useful range of fault conditions to be evaluated, improving the protection for the circuit.

The programmable condition may comprise a current difference threshold and evaluating the first current measurement may comprise: determining a difference between the first current measurement and the second current measurement; and comparing the difference with the current difference threshold.

This can allow the programmable controller to emulate the function of an RCD. However, unlike a conventional RCD, which trips at a fixed current threshold, the current difference threshold of the programmable controller can be programmed at any desired level.

The distribution board may further comprise a third sensing device configured to sense a current flowing through the input connection of the distribution board, to generate a third current measurement; and the programmable controller may be configured to: receive the third current measurement from the third sensing device; evaluate the third current measurement against a further programmable fault condition; and if the programmable fault condition is met, trigger a further remedial action.

The further programmable condition may comprise a further current threshold.

This can allow the programmable controller to provide collective protection for all of the ways together. It can also act as a second level of protection - for example, in the event that the first current sensing device fails.

The third sensing device may be configured to sense a current flowing in a live conductor at the input connection, and the distribution board may further comprise a fourth sensing device configured to sense a current flowing in a neutral conductor at the input connection, to generate a fourth current measurement.

The further programmable condition may comprise a further current difference threshold and evaluating the third current measurement may comprise: determining a difference between the third current measurement and the fourth current measurement; and comparing the difference with the further current difference threshold.

The remedial action may comprise at least one or any combination of two or more of: activating an alarm; sending a warning message to a remote device; and recording the occurrence of the fault condition in a memory.

The programmable controller is optionally further configured to monitor an energy consumption of each circuit and report energy consumption measurements to a user or to a remote device.

The distribution board may further comprise a communications interface coupled to the programmable controller, configured to allow the programmable controller to communicate with a remote device.

The programmable controller may be programmable via the communications interface.

The programmable controller may be configured to send a warning message to a remote device via the communications interface.

The communications interface may comprise a wired interface, such as a Wide Area Network (WAN) interface or Local Area Network (LAN) interface, or it may comprise a wireless interface, such as a Wireless LAN (WLAN) interface.

The programmable fault condition may comprise a current deviation threshold; and evaluating the first current measurement against the programmable fault condition may comprise comparing the first current measurement with an expected current value, wherein the remedial action is triggered if the difference between the first current measurement and the expected current value is greater than the current deviation threshold.

This allows the distribution board to monitor changes in the current drawn over time. If the current drawn by the circuit changes by more than the current deviation threshold, the remedial action is triggered - for example activating an alarm; or sending a warning message to a remote device.

The inventor has recognised that, in many kinds of electrical equipment, failure of the device is often preceded by a period of operation in which the device draws an uncharacteristic amount of current. For example, before a motor fails, it is common to see an increase in the current drawn. The controller of the distribution board can monitor for such uncharacteristic variations and can warn the user accordingly.

The expected current value may be programmed, or may be a historical current measurement that was measured previously by the first sensing device. The historical current measurement may be stored in a memory of the controller.

Each way optionally comprises a manually operable isolating switch for selectively disconnecting the output connection of the way from the input of the way.

This offers a further level of protection. The manual switch may be opened to isolate the circuit when servicing the distribution board or when a working on the circuit.

The distribution board optionally further comprises a main isolating switch for selectively disconnecting the distribution board from the electricity supply.

At least one (and preferably all) of the following switches comprises a double pole switch: the electrically controllable switch; the manually operable isolating switch; and the main isolating switch.

The distribution board may further comprise a user interface coupled to the programmable controller.

The programmable controller may be programmable via the user interface.

The programmable controller may be configured to notify the user of the activation of an alarm via the user interface.

The programmable controller may be configured to report energy consumption measurements to a user via the user interface.

The user interface preferably comprises a touch sensitive display screen.

The touch sensitive display may comprise a Liquid Crystal Display (LCD).

According to another aspect there is provided a method of commissioning an electricity supply system, the method comprising: installing a distribution board according to any one of the preceding claims; and programming the programmable controller with at least one programmable fault condition for each way.

The method preferably further comprises programming the programmable control with a remedial action associated with each programmable fault condition.

The programmable controller may be programmed via a user interface of the distribution board or via a communications interface of the distribution board.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example with reference to the accompanying drawings, in which:

Fig. 1 is a schematic circuit diagram for a distribution board according to an embodiment of the invention;

Fig. 2 is a perspective view illustrating an external appearance of the distribution board in Fig. 1;

Fig. 3 shows the distribution board of Fig. 2 in a different configuration;

Fig. 4 shows the distribution board of Fig. 2 opened for commissioning or servicing.

It should be noted that these figures are diagrammatic and not drawn to scale. Relative dimensions and proportions of parts of these figures have been shown exaggerated or reduced in size, for the sake of clarity and convenience in the drawings.

DETAILED DESCRIPTION A distribution board according to an embodiment of the present invention is similar to known distribution boards in that it has “ways” to which the outgoing circuits connect and which serve the outgoing circuits, such as power socket circuits, lighting circuits etc. Unlike known distribution boards, a distribution board according to an embodiment is programmable, preferably interactively programmable by the user or installer. A schematic circuit diagram of a distribution board according to an embodiment is shown in Fig. 1. The distribution board, comprises an input connection 10 for coupling to an electrical supply; and a plurality of ways 20. Each way 20 has an input that is coupled to the input connection 10 of the distribution board and has an output connection 21 for coupling to an electrical circuit. For the sake of clarity and simplicity, four ways 20 are shown in Fig. 1. However, the distribution board can be designed with any desired number of ways. The number of ways will typically be greater than four, in practice.

Figs. 2-4 show the external appearance of the distribution board according to one embodiment.

The distribution board comprises an enclosure or housing 70, which is preferably manufactured from metal for improved fire containment. The external appearance of the distribution board is preferably aesthetically pleasing or attractive. This can allow it to be mounted more prominently would normally be considered for a distribution board.

The front of the distribution board comprises an interactive touch screen display 50, similar to a tablet computing device. This will switch off to exhibit a mirrored finish, when the display is idle. The display 50 is mounted by hinges to the housing 70. This allows the display to rotate outwardly when a release-button 72 in the housing 70 is pushed. Fig. 2 shows the distribution board with the display 50 in the closed position. Figs. 3 and 4 indicate the position of the display 50 when it is open. A separate lid 80 covers the main isolating switch 48. When operated, this will switch the whole distribution board on or off. Fig. 2 shows the lid 80 closed. Fig. 3 shows the lid 80 open, revealing the main isolating switch 48. The lid 80 and switch 48 are not shown in Fig. 4, for simplicity.

Behind the display 50 is a removable metal cover 90 which covers the internal electrical components. This increases the safety of the distribution board, by improving fire containment. When removed, as shown in Fig. 4, the removable cover 90 reveals manually operable isolating switches 28 to enable physical switching or isolation of each way 20. In this example, the switches 28 are sliding switches. These are lockable in the off position, to improve safety while an electrician is working on the circuit connected to the respective way 20.

The distribution board is interactively programmable, to allow a qualified installer or qualified post-installation electrician to select the ampere rating (current rating) of each way, the type of tripping characteristic of each way (Type B, C or D), whether the way is to be RCD protected and the tripping current of the RCD. These parameters can be configured by programming the distribution board. Preferably, the distribution board is programmed using a connected computer (not shown), loaded with custom software. The computer can be connected to the controller of the distribution board via a LAN, WAN or Wireless connection 60.

The distribution board has current transformers 22, 24 connected to the live and neutral conductors, respectively, of each way. These act as sensing devices, to monitor the current flow in and out of the way. Similarly, at the input connection 10 of the distribution board, the main supply also has current transformers 42, 44, monitoring the main supply flow and return current values, respectively.

Each way 20 can be switched off in an overload or earth fault condition by built in contactors 26 that are fitted to the way 20. The contactors 26 are electrically controllable switches. In this example, they are electromechanical relay devices. In other embodiments, they could be constructed using power semiconductor devices.

Each contactor 26 is controlled by the programmable controller 30. The controller comprises an electronic control circuit 32 provided on a Printed Circuit Board (PCB) and a programmable microcontroller (or microprocessor) 34. Each contactor 26 is connected to the control circuit. The control circuit in turn is connected to the programmable microcontroller or microprocessor. The current transformers 22 and 24 are also connected to the control circuit 32, to allow the microcontroller to monitor the instantaneous current usage in each way 20. If the instantaneous current flowing in the way 20 exceeds the programmed rating of the way, the contactor 26 is opened by the controller 30. For example, a lighting circuit might be connected to a way 20 of the distribution board, and that way might be programmed to trip at a current threshold of 10 A. If this current is exceeded (as measured by the current transformers 22, 24), the contactor 26 is opened to prevent an overload of the circuit.

For the sake of clarity and simplicity, the connections to the controller 30 are only shown explicitly for the left-most of the four ways in Fig. 1. However, it will be understood that each of the other three ways also comprises identical connections (i) between the controller 30 and the contactor 26; and (ii) between the controller 30 and the current transformers 22, 24.

In each way 20, the current transformers 22, 24 also measure the flow and return currents. If the controller 30 detects an imbalance in these currents, the contactor 26 will be opened. This programmable option is earth leakage protection as normally afforded by an RCBO in a known distribution board.

In addition to opening the contactor 26, the controller 30 can send a warning message notifying a user by LAN, WAN or wireless connection 60 that a way has been switched off. The controller 30 can also inform the user of the reason for switching of the way (such as overloading or earth fault). The notification can be made to a connected computer with custom software installed, or to any other remote device, such as a smartphone.

Another feature of the distribution board is that a “normal” or “expected” current value (in amperes) can be programmed for any of the ways 20. If the current measured by the current transformer 22 or 24 deviates from this expected current by more than a programmed threshold, an alarm signal is sent to the monitoring computer via the WAN, LAN or Wireless connection 60. This can be useful for monitoring important equipment. For example, if an important item of equipment is connected to a separate radial circuit, the normal operating current for that circuit can be measured by the built in current transformers 22, 24 and that operating current can be programmed into the controller 30 or stored automatically by the controller 30 in a memory 36. If the item of equipment becomes faulty, the first usual “symptom” is that the current drawn by the equipment increases. When the current drawn exceeds the programmed (or stored) level by a predefined amount, an alarm will be sent to the monitoring computer through the LAN, WAN or wireless connection 60. A further feature of the distribution board is the possibility to monitor energy usage in various ways. For example, the controller 30 could be programmed to monitor the overall energy usage through the distribution board in a user-defined period such as year, month, or week. Alternatively or in addition, the controller 30 could be programmed to monitor instantaneous usage of energy through the distribution board. In another example, the energy usage of each individual way could be monitored separately, in a user-defined period such as year, month, or week. Or, again, the usage could be monitored instantaneously. Monitoring of the individual ways may be particularly useful for determining which of the circuits is using the most energy and therefore causing the most cost to the user. This may assist the user to identify the electrical device or appliance that is using the energy. The user can then take action to reduce the energy consumption, if required.

Energy usage can be monitored by monitoring current only (using the current transformers 22 and 24) and assuming a constant supply voltage. Power (that is energy used per unit time) can be calculated as a product of current and this constant voltage. Alternatively, both current and voltage can be measured and a product of these measurements can be calculated by the controller 30.

In some embodiments, a user can remotely log-on to the distribution board via the LAN, WAN, or wireless connection 60, which functions as a communications interface. This allows the user to inspect information about the ways, such as status, power consumption, etc. The user may remotely log on from a remote device such as a connected computer loaded with custom software. Access may be controlled by password protection. Using this function, for example, a landlord could determine what current / energy has been used at a rented property. This would allow him/her to charge the cost of this usage to the tenant.

In another example, a maintenance company may maintain a portfolio of properties. A technician from the company can log-on to view the status of a circuit if an alert is received indicating that the circuit has switched off. The technician can view what caused the circuit to switch off. In some circumstances, it may be appropriate to reset the circuit remotely. This can be done by sending an instruction to the controller 30 via the LAN, WAN, or wireless connection 60. The controller 30 then closes the contactor 26, to restore power to the way 20. This may avoid the need to visit the property, thereby reducing costs.

The aesthetically pleasing design of the distribution board illustrated in Figs. 2-4 means that it can be mounted in full view wherever a customer wishes (subject to safety regulations). This can avoid the need to hide an unsightly distribution board out of sight as was often done in the past.

To commission an electricity supply system, the installer installs the distribution board. This can be installed in essentially the same manner as conventional distribution boards. In particular, each way has live and neutral terminals at its output connection 21, which can be wired by the installer in the same way as the terminals on a conventional distribution board. After installing the distribution board, but preferably before switching on the main isolating switch 48, the installer programs the programmable controller 30 with at least one programmable fault condition for each way. This may comprise inputting a current threshold, current difference threshold, or current deviation threshold, as discussed previously above. The controller 30 may be programmed via the communication interface (LAN/WAN/WLAN connection 60). Alternatively, the controller 30 may be programmed using a user interface displayed on the display touch screen 50. Optionally one or more remedial actions associated with each fault condition may be programmed as well. For example, a current threshold may be associated a first remedial action comprising opening the contactor 26 and a second remedial action comprising sending a warning message via the LAN/WAN/WLAN connection 60.

Embodiments of the invention may be useful in a variety of applications, for a variety of reasons. Some of these will now be discussed.

Most premises that have an electrical supply (including but not limited to houses, offices, and factories) have a distribution board of some kind. Conventionally, this distribution board contains MCBs, RCBOs, cartridge fuses or, in older installations, fuse wire carriers. These distribution boards are designed to protect the electrical installations of the buildings they serve by interrupting the electrical supply during a fault condition, such as an overload or earth fault. The technology of distribution boards has changed slowly and minimally over the decades. Embodiments of the present invention can overcome many problems that the known distribution board arrangements have not addressed.

The conventional modern distribution board contains either MCBs or RCBOs. These devices have various fixed sizes or ratings such as 6, 10, 16 or 20, 32, 40 ampere and many other sizes depending on the circuit that they are protecting. In conventional distribution boards, protective devices made by different manufacturers are often unique in some way, and each manufacturer has many different types, sizes and ratings of protective devices, meaning that a huge number of options is available. This causes problems when installing a distribution board. The desired sizes (or ratings) of the protection devices for a given electrical installation are usually chosen and purchased with the distribution board itself. If the correct sizes are not selected, the unused devices will need to be returned and new correct sizes ordered. If the mistake is only discovered at the installation site, this can be costly and it may cause considerable delay to obtain the correct parts.

In the case of an alteration or addition to an existing electrical installation, additional protective devices or devices with a different size/rating may be required for the existing distribution board. If the existing distribution board is no longer in production, protective devices that are interoperable with that board may be difficult to obtain or no longer available. This may mean lead to delays and cost increases, or - in extreme cases - may mean that the whole distribution board has to be changed.

Distribution boards according to embodiments of the present invention allow each way to be protected by a set of programmable rules. These rules can be customised to emulate known protective devices, such as MCBs and RCBOs, but they have several advantages over the known protective devices. Because the fault condition can be customised freely, the system is not limited to using a fixed set of current ratings or a fixed set of MCB types. And because the fault conditions (and optionally remedial actions) are programmable, there is no need to choose a specific set of protective devices in advance. The distribution board can be configured to provide any desired combination of protection for the different circuits and this can be reconfigured easily later if necessary. All that the installer needs to ensure is that the distribution board has a large enough number of ways to match the number of circuits in the installation.

Some circuits - particularly in commercial electrical installations -provide power for very important or essential equipment. If, for some reason, a fault develops in one of these mission-critical circuits, and a vital piece of equipment fails, this may have serious and expensive consequences. For example, if a building has a basement or boiler room that is vulnerable to flooding, a sump pump is often installed to pump away the unwanted water. If the electrical supply to the sump pump were to fail this might not be noticed until it is too late - in particular, after a flood has already happened. This may have disastrous consequences, such as expensive repair costs and/or damage or destruction of potentially irreplaceable items Another example could be the electrical supply to a computer server in a business. If this were to fail it could inflict significant financial harm on the company through lost business and loss of reputation, if the server is responsible for a key operational function. Other examples may arise in the field of healthcare. A Hospital may have certain circuits that are essential for patient care and/or that run potentially life preserving equipment.

According to embodiments of the present invention a user may interact with a distribution board wirelessly or through a LAN or WAN connection, meaning that the distribution board can be programmed and inspected locally or remotely. According to one exemplary remedial action, the distribution board is operable to send messages to a user-programmed email address upon detection of a fault condition.

The distribution board may have built in current transformers that are configured to monitor the loading of every individual circuit in an electricity supply system. The controller may also monitor the status of the contactors -in particular, whether they are open or closed and whether or not they have been tripped in response to detection of a fault condition.

This can allow the distribution board to be programmed to monitor essential circuits (such as the examples detailed above). If a circuit fails and the controller switches off that circuit as a result of the fault condition, the controller can be programmed to electronically send notification of the problem via an email message or by prompting an alert on a monitoring computer that has appropriate monitoring software installed. A maintenance company could provide the service of monitoring for such events. Technicians of the maintenance company could be provided with access to log in remotely to the distribution board and reset the switch remotely. Alternatively, the remotely located technician could notify an engineer to attend and repair the faulty circuit or faulty equipment connected to it.

Embodiments of the present invention may also help to protect vital equipment in other ways. Many types of electrical equipment draw an approximately constant level of current when running normally. This is true in particular for electric motors, which are found in pumps and air-conditioning systems, for example. Pumps can be vital equipment if they protect against flooding. Air-conditioning can be vital when it is needed to cool a computer server - if the air-conditioning fails the server will overheat and will either shut down to protect itself or else it may fail. If the motor or other item of equipment becomes faulty, the current drawn begins to increase (either gradually or suddenly). In the case of a motor, this could happen as a result of the bearings becoming seized, but other equipment may fail in other ways with a similar characteristic increase in current. In the case of a computer server, for example, the current increase might be caused by the power supply becoming overloaded. In conventional electrical installations, the current eventually increases sufficiently to trip an MCB. This is often at a point of irreversible failure - the equipment can no longer continue to be used safely at this stage; therefore, it must be repaired or replaced before switching the circuit on again. In this way, the user only becomes aware of the problem at the point when the equipment fails and needs immediate attention. By that time, the equipment failure may have caused additional consequential damage or financial loss.

According to embodiments of the present invention, the distribution board can monitor the current in each way, to detect the characteristic increase in current exhibited by failing equipment. The controller can be programmed to trigger an alarm if the measured current exceeds a preprogrammed maximum value. This value may be lower than the tripping current for opening the contactor to disconnect the circuit from the electricity supply. The alarm may comprise a signal that is sent to a computer configured to monitor the distribution board, via a LAN/WAN/WLAN connection. The monitoring of the current can be done using current transformers in each way of the distribution board, as described already above.

For example, if a pump draws a current of 12 A during normal (fault-free) operation, the controller could be programmed to monitor that load. If the pump develops a fault (such as a blockage, seized bearing, or the like), then typically the current load that it draws will increase. The controller would then detect this breach of the set value of load (for example, 15 A) for that circuit and would electronically communicate with a user or remote device to provide a warning that there is a problem This early warning may allow repair or replacement of the faulty pump, before the problem worsens or more significant and expensive damage occurs. In the case of a very sudden, rapid failure, preventative repair might not be possible, but the distribution board will still provide the earliest possible notification of the problem, so as at least to enable a quick response (for example, ensuring that an engineer attends as soon as possible).

Embodiments of the present invention can also support the monitoring of energy usage, without any increase in the cost or complexity of the distribution board. Modern regulations require any commercial installation having an area of greater than 1000 m2 to have load-meters fitted to the distribution board to monitor energy usage. Increasingly, domestic installations are also utilising load monitoring connected externally to the distribution board, so that consumers can monitor their energy usage carefully. This becomes more important as energy costs rise. Of the available solutions for monitoring energy consumption, most are retro-fitted and many are untidy and unattractive.

According to embodiments of the present invention, the distribution board can allow monitoring of the current or power usage through each way of the distribution board, and therefore in each connected circuit. It can also allow the overall load of the board to be monitored. The usage can be reported to a user locally, for example via the touch screen display, or to a remote device, such as a computer or smart phone. The energy used can be calculated by monitoring the current drawn in each way, using the current transformers as described previously above. The ability to monitor energy consumption can be useful for a “direct” consumer, such as an owner-occupier in his/her own home. It can also be useful in the context of “indirect” consumers of electricity, such as in rented accommodation. If a landlord or owner wishes to bill a tenant for electricity usage, then the landlord or owner (or letting agent or other representative) could log-on to the distribution board (optionally remotely) and could download a report of what energy the tenant used in a particular period.

Embodiments of the invention can also enhance fire protection. The latest amendment to the BS7671 wiring regulations requires distribution boards to contain fire (such as a fire caused by a loose connection within the distribution board). Manufacturers are now producing steel distribution boards to meet the regulation and plastic distribution boards will no longer be manufactured in future.

Embodiments of the distribution board can be manufactured from a steel enclosure to meet the latest regulations. The steel enclosure can enclose the contactors, current transformers and all mains elements of the distribution board. A metal cover can be provided behind the display screen to create the required fire proofing. A thermistor can be mounted on this internal metal plate, to monitor for excessive heat levels. Distribution boards and cables are designed to run at a temperature above ambient temperature in most cases, but heat generated by a loose connection can quickly rise to combustion levels. The thermistor may be connected to the controller of the distribution board. If the controller detects an increase in temperature above a set value determined to be the maximum safe temperature value, it may isolate the board by disconnecting the incoming electrical supply thereby preventing a more serious failure of the distribution board by opening contactors. If necessary, it could reduce the load to zero by opening all of the contactors or opening the main isolating switch, thereby removing the cause of a potential fire. Furthermore, this remedial action could be reported immediately to the user by the wireless, LAN or WAN connection and/or locally via a visual and/or audible alarm built into the display.

Conventionally, distribution boards are hidden from view - for example, in cupboards. In smaller dwellings, users have no choice but to have the distribution board on display somewhere. They are almost always an unattractive feature. According to embodiments, the aesthetically pleasing finish of the distribution board may allow the board to be installed in visible places that would not normally have been considered in the past for known distribution boards.

Although manufactured from a steel enclosure to meet the latest wiring regulations, distribution boards according to embodiments can be presented in an attractive and modern case. The front of the distribution board may present a glass touch screen display. When not in use, this display can appear like a mirrored glass finish. Optionally, when the screen is touched, it may display the status of each way (that is, on or off), the load being drawn by each way, the overall load of the whole distribution board, the voltage on the system and a log-in section.

Access controls may allow different levels of access to different users or classes of user. For example, a tenant renting a property may be able to turn a circuit on or off, in the same way as can be done with the circuit breakers on known distribution boards. However, the tenant would not be able to make any configuration changes to the distribution board without a correct password.

Wiring standard BS 7671 requires that domestic and commercial installations have a periodic electrical test and inspection - usually at a maximum interval of 5 years. Landlords, in particular, need to ensure compliance with this regulation, for insurance reasons as well as other legal and health and safety requirements.

According to embodiments, the distribution board can have a nonvolatile memory that can retain the programmed settings and that can also be used to store other information such as energy usage. A further use of the memory will be the facility to program the last test and inspection date and set the interval for the next due test and inspection. The controller can then generate a local message and/or an email message to the user to remind him/her of the due date.

The embodiments may be implemented by means of hardware comprising several distinct elements. In a device claim enumerating several components or functional units, several of these may be embodied by one and the same item of hardware.

In general, the various embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although these are not limiting examples. While various aspects described herein may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as nonlimiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The embodiments described herein may be implemented by computer software executable by a data processor of the apparatus, such as in the processor entity, or by hardware, or by a combination of software and hardware. Further in this regard it should be noted that any blocks of the logic flow as shown in the drawings may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD.

The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), gate level circuits and processors based on multi-core processor architecture, as nonlimiting examples.

Embodiments as discussed herein may be practised in various components such as integrated circuit modules. The design of integrated circuits is typically a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. A distribution board for an electricity supply system, the distribution board comprising: an input connection (10) for coupling to an electrical supply; and a plurality of ways (20), each way having an input coupled to the input connection (10) of the distribution board and having an output connection (21) for coupling to an electrical circuit, each way comprising a first sensing device (22), configured to sense a current flowing through the way, to generate a first current measurement, the distribution board further comprising a programmable controller (30) configured to, for each way: receive the first current measurement from the first sensing device (22); evaluate the first current measurement against a programmable fault condition; and if the programmable fault condition is met, trigger a remedial action.

2. The distribution board of claim 1, wherein each way comprises an electrically controllable switch (26) for selectively disconnecting the output connection from the input of the way; and the remedial action comprises controlling the electrically operable switch to disconnect the output connection from the input of the way.

3. The distribution board of claim 1 or claim 2, wherein the programmable fault condition comprises a current threshold.

4. The distribution board of any one of the preceding claims wherein, in each way: the first sensing device (22) is configured to sense a current flowing in a live conductor of the way, and the way further comprises a second sensing device (24) configured to sense a current flowing in a neutral conductor of the way, to generate a second current measurement.

5 The distribution board of claim 4, wherein the programmable fault condition comprises a current difference threshold and evaluating the first current measurement comprises: determining a difference between the first current measurement and the second current measurement; and comparing the difference with the current difference threshold.

6. The distribution board of any one of the preceding claims, wherein the remedial action comprises at least one or any combination of two or more of: activating an alarm; sending a warning message to a remote device; and recording the occurrence of the fault condition in a memory.

7. The distribution board of any one of the preceding claims, wherein the programmable controller is further configured to monitor an energy consumption of each circuit and report energy consumption measurements to a user or to a remote device.

8. The distribution board of any one of the preceding claims, further comprising a communications interface (60) coupled to the programmable controller (30), configured to allow the programmable controller to communicate with a remote device.

9. The distribution board of any one of the preceding claims, wherein: the programmable fault condition comprises a current deviation threshold; and evaluating the first current measurement against the programmable fault condition comprises comparing the first current measurement with an expected current value, wherein the remedial action is triggered if the difference between the first current measurement and the expected current value is greater than the current deviation threshold.

10. The distribution board of any one of the preceding claims, wherein the electrically controllable switch (26) comprises a double pole switch.

11. The distribution board of any one of the preceding claims, further comprising a user interface (50) coupled to the programmable controller.

12. The distribution board of claim 11, wherein the user interface comprises a touch sensitive display screen (50).

13. A method of commissioning an electricity supply system, the method comprising: installing a distribution board according to any one of the preceding claims; and programming the programmable controller (30) with at least one programmable fault condition for each way.

14. The method of claim 13, further comprising programming the programmable controller with a remedial action associated with each programmable fault condition.

15. The method of claim 13 or claim 14, wherein the programmable controller (30) is programmed via a user interface (50) of the distribution board or via a communications interface (60) of the distribution board.