Electrical Board

1) What is an electrical board?

An electrical board is the beginning of the consumers electrical installation that belongs to them. The incoming mains supply is a large thick cable that enters into a ‘supply cut-out’ and then from there goes to the electric meter. Once the supply has passed through the electric meter it enters into the electrical board where the supply is divided into various electrical circuits.%20

The electrical board is a large and normally rectangular box that contains various electrical devices such as fuses, trip switches and other components that enable the electrical system to function safely and offers protection to the cabling and electrical accessories within an electrical system.%20

2) Typical names for an electrical board

• Consumer unit – Typically a plastic or metal box containing switches with differing purposes
• Fuse Box – A metal or plastic box containing fuses, fuse carriers (containing fuse wire) or switches.
• Fuse Board – Essentially the same as a fuse box with a different name.%20
• Electric Panel – More typically used in the Americas to describe the consumer unit, distribution board or fuse box.
• Main Board – The primary electrical distribution board or panel in an electrical system.
• Distribution Board – The electrical enclosure containing the equipment that separates the electrical supply into electrical circuits.
• Trip Switch Box – This is a more modern version of the fuse box and is also known as the electrical panel or consumer unit. Named ‘trip switch box’ as it contains the electrical switches that typically trip in the event of an electrical fault.

3) What does an electrical board do and how does it work?

An electrical board receives the mains electrical supply and safely splits this into smaller supplies that feed various parts of an electrical system. How small the supply is split will depend upon the type of electrical circuit that is being fed, the cable sizes and the demand of any electrical equipment that needs to be powered.%20

The electrical board contains devices that protect cables from overload, damage, and overheating. More modern electrical boards contain devices that protect against ground (or earth) faults which also protect us against electric shock.%20

The electrical board has to be correctly designed and installed by a professional to ensure that there is adequate protection for circuits, equipment, and lives.%20

4) What are electrical circuits?

An electrical circuit is a continuous loop of electrical cable that allows electrical current to flow to electrical equipment that requires it. The circuit must contain Line and Neutral or Hot and Neutral wires to function correctly in most cases. The electrical equipment is connected in parallel across the Line and Neutral wires so electrical current can efficiently flow through it.

Typical examples of electrical circuits would be:

• Plug Sockets Circuit
• Lights Circuit
• Electrical Cooker Circuit

Each of these circuits would generally be protected by a different device at the electrical board. Each circuit would use larger or smaller cables depending upon the required design characteristics and anticipated electrical demand.%20

5) What are the various components within an electrical board?

The Main Switch is a point of Isolation for all electrical circuits within the electrical board. This device receives the incoming street power supply via the supplier’s fuse and equipment and allows for the supply to reach each of the electrical circuits via a busbar. We can see what a main switch looks like from the labelled photograph below.

The Busbar is the rigid metalwork that connects the Main Switch to all circuits. There are sometimes one or more Busbars in an electrical board depending upon the type of equipment that is installed. The Busbar typically has prongs that insert into the bottom of each circuit breaker to feed the supply in.%20

Circuit Breakers are the individual circuit protective devices that limit the amount of electrical current that can flow in the electrical circuit. It is important that careful design and planning is carried out when sizing these devices as they are in place to prevent electrical fire, overload, and short circuits from causing damage to cables, electrical installation, and the home.%20

GFCI or RCD switches are devices that detect any missing electrical current in a circuit and trip when there is an imbalance between the electrical current flowing in Hot and Neutral. These devices are in place to prevent electric shock and can also provide a small degree of fire protection. These devices will occasionally trip for no seemingly good reason. There is always a reason for these devices tripping and it should be investigated by a professional.%20

6) What different types of electrical board are there?

3 phase – This type of electrical board accepts three incoming live supplies. These are generally used in very large homes or more typically, commercial, and industrial applications where three – phase equipment requiring a lot of power will be used.

16th edition – UK 16th Edition electrical boards have GFCIs / RCDs installed on most circuits (except lighting) and were installed between 1991 and 2008.

17th edition – UK 17th Edition electrical boards generally have 2 GFCIs / RCDs installed protecting all circuits and were installed between 2008 and 2018.

18th edition – UK 18th edition electrical boards have so far been installed since 2018 and will continue to be installed until the 19th edition wiring regulations BS7671 come into force.%20

7) Is it safe to mix and match components in an electrical board?

Generally, it is NOT safe to mix and match components in an electrical board. Manufacturer’s design and build their equipment to different specifications of size, fault current discharge direction and heat dissipation locations. Manufacturers test their equipment inside their enclosures under fault conditions and normal operating conditions and declare the switchgear and equipment safe to use as assembled.%20

When other manufacturers equipment is installed within another manufacturers enclosure it is often a different size or shape meaning modification is necessary in order to obtain a fit. Even if the equipment appears to be moulded in exactly the same way this does not mean that the other characteristics of the equipment are compatible or safe to use with different brands.%20
We can see from this close up photograph that there are 4 or 5 different brands mixed in this consumer unit and this is causing problems!!!

Express permission should be obtained from the manufacturer before installing other branded equipment into enclosures such as electrical boards. Occasionally, brands change name and model names and confirmation of compatibility can be obtained.%20
Under the United Kingdom wiring regulations BS7671, regulation 536.4.203 covers the circumstances around mixing differing manufacturers equipment in enclosures. A copy of the IET wiring regulations can be purchased HERE

8) What is a main board in electrical speak?

The Main Board often refers to the master panel or primary electrical board in an electrical installation. In Larger electrical systems it is not uncommon to have several electrical boards installed that control different parts of an installation. Occasionally these boards are within different buildings or rooms and will often be fed from a larger or main board at the origin of the installation.

9) Can a main board be repaired?

The likelihood of repair to a main board will depend upon many factors such as:

• The age of the board
• The availability of equipment
• The extent of any damage
• The likelihood of a successful repair
• The wiring regulations and limitations within these for safe repair
• The financial implications of the repair vs replacement
• Any damage to wiring within the board

10) Is an electrical panel a fuse box?

Essentially, they perform the same job. An electrical panel, electrical board, distribution board, consumer unit, fuse box, fuse board, trip switch box or electrical box all contain the incoming electrical supply and distribute it around the electrical installation through the electrical wiring. They all offer some degree of cable protection and overload protection for the electrical installation. More modern electrical panels will have up to date equipment that offers protection beyond that of a simple fuse box.
The fuse box typically contains fuse wires or fuses which are basic technology compare to an MCB (Miniature Circuit Breaker) or RCBO (Residual Current Breaker with Overload). Fuses still offer protection from overload or short circuits but the more modern equipment offers better protection such as electric shock protection and protection against electrical arcing and fire.%20

11) How big can an electrical board or panel be?

Electrical panels can range from a single Main Switch and circuit breaker through to many circuit breakers. Smaller electrical panels tend to be installed into domestic premises and contain fewer circuit breakers that control fewer circuits.%20

Typically, a garage consumer unit will contain just two circuit breakers and be no larger than 10 x 15 inches in size. These two circuits will generally power a plug socket circuit and a lighting circuit. Any powered garage doors will normally be installed on the circuit that power the plug sockets.%20

The electrical board / panel for the main home will range from 6 circuit breakers for small homes up to 20 circuit breakers for larger homes. Where more circuit breakers are required then the panel is normally a three-phase panel but these would be installed in to manor homes or commercial premises.%20

Commercial and Industrial electrical boards / panels can reach several feet in height and width.%20

12) How much should it cost to replace an electrical board?

Unsurprisingly, it depends. I appreciate that this answer is not helpful to most people reading this but let me explain.%20

The larger the premises, the larger the electrical installation and the more circuit breakers and the more testing is required in order to complete this type of job. There can also be pre-existing electrical faults hidden in the system that require rectification before the electrical board can be safely installed or the circuits safely connected and re-energised.%20

As a general rule in 2024 the costs for replacing an electrical panel in the US can be anything from $400 to $5000 depending upon the size of panel and any issues that require putting right.%20

In the UK in 2004 the average cost can be £400 for a small garage panel with no existing problems up to £5000 for a large commercial panel that also has electrical issues in the system that require sorting first.

The best option is to have a conversation with your electrician about your electrical system and what may be required. It is often a good idea to have an electrical inspection carried out prior to the electrical board being changed. An electrical inspection will highlight any electrical faults that need to be found and corrected before a board is replaced and a quote for works can then be arranged.%20

13) How long does it take to replace an electrical board?

Assuming that the electrical board contains 8 electrical circuits, there are no problems that need to be fixed and all equipment is on site ready to go then the electrical board, testing and certification can be completed within 8 hours.%20

The larger the electrical board, the poorer the access to the site and the more testing that is required the longer the job will take to complete. Other factors can affect the time taken to replace the panel such as:

• Other electrical equipment that requires moving
• Circuits that require extending
• Faults that need to be found and fixed
• Removal of the old panel and any complications
• Access to electrical points in the building for inspection and testing purposes
• Any making good that needs to be carried out

14) What are typical problems with an electrical board?

There are a few things that can go wrong with an electrical board and when they do, they can mean a total board replacement is necessary.

• Excessive power consumption causing burnouts to occur
  - Components can get hot and overheat causing melting
  - Neutral bars, Earth bars and Busbars can overheat causing damage to other components in the board
• Loose connections can cause fire or melting and require that components are replaced or in more serious cases, the entire board. The photograph below shows an entire electrical board that MUST be replaced.

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• Switches tripping
  - Often the reason for a switch tripping is an issue with the electrical circuit or connected equipment
  - Switches can also trip when they go faulty
• Fuses blowing
  - Fuses can overheat and blow through excessive power consumption in the electrical system
  - Fuses can blow when there are dangerous electrical faults in the system
• Main Switches can fail
  - Usually this occurs when loose wiring causes overheating
  - This can also occur when worn out main switches fail internally%20
• RCD / GFCI devices can fail through electrical faults and constant resetting of the device

15) What is the best make of electrical board?

There are many different brands and models of electrical boards on the market and each will have its strengths and weaknesses. One of the most important things to consider when purchasing an electrical board is the likelihood of replacement equipment in the future. In Europe for example there is a German brand of electrical board that has been in manufacture for years which has great backwards compatibility with older equipment from the same manufacturer. This type of board is generally more expensive to purchase than other manufacturers equipment BUT spares are available and it has a great reputation and company longevity.

There are many cheaper brands on the market that do the same job and are no doubt very reliable but will occasionally change the design of the equipment in the electrical boards which makes backwards compatibility difficult or impossible and will mean should the equipment fail in the future that the whole electrical board may need to be replaced.%20

There is also the unknown long term reliability question over new-to-the-market electrical board brands and of course whether the manufacturer will continue to produce the same equipment in the same dimensions and style!%20

There is no ‘best brand’ to speak of when it comes to electrical boards and it is best to talk with your electrician to establish what they recommend, what they will install and are happy to warranty for you. Electricians generally have a good idea of what brand of equipment is the best for various reasons and for your budget.%20

It is always possible to purchase extra components at the time of installation for the electrical board should the need arise in the future.%20

16) How do I choose the type of electrical board?

When choosing a new electrical board to install it is vital that the wiring regulations in force at the time of installation are consulted. Safety wiring regulations change occasionally and this will mean that some equipment on the market is no longer suitable for installation under certain circumstances.%20

GFCI and RCD devices are now virtually compulsory in many situations so simply installing an electrical board with MCB devices is often not compliant with the wiring regulations.%20

Other factors to consider for the type of electrical board that should be installed are:

• Material of construction
• Type of electrical board
  - Populated with equipment
  - Non-Populated equipment
• Ease of installation
  - Knock out holes make installation easier
  - Taller electrical boards leave room for installing wiring more easily
  - Din Rail and Busbar configurations can be better with different manufacturers
• Quality of equipment

17) Can I replace an electrical board myself?

No, this type of work is specialised and will require a variety of skills, qualifications, knowledge, and tools that the average DIY enthusiast or other trade does not possess. You may also be in violation of certain laws, rules and guidelines depending upon your country or territory.%20

Whilst it is tempting to try and save money on installation costs for your new electrical board, the selection, installation and testing of equipment and electrical installations is a professional job only and any attempt to install equipment by anyone other than an electrician is likely to lead to electric shock, harm, or danger in other ways.

18) Can an electrical board be in a cupboard, bathroom, or garage?

It is not uncommon to find this type of equipment installed in cupboards, bathrooms, or garages. The wiring regulations do change over time so it is possible that when the equipment was installed that everything complied at the time but now with a change in regulations, electrical equipment may be considered dangerous in its installed location.%20

Check with your local electrician to see if the equipment is installed safely in its current location and whether it needs to be moved. If you are based in the UK, we are happy to help you with this free of charge as we are always up to date with the wiring regulations BS7671 and can normally advise if an electrical inspection may be needed or a relocation of equipment. Use our contact form to get in touch.

The photograph shows an electrical board installed in a small cupboard. Whilst this does not comply with the most up to date wiring and building regulations in the UK for example, it is not illegal and does not require changing for this reason. It does however mean that anyone not able bodied would seriously struggle to operate switches which may be necessary following an electrical fault.

This was installed in a small kitchen cupboard at floor level with a shelf immediately above!!

19) What are the three types of conductors found in an electrical board?

You will find the Line / Hot conductors, the Neutral conductors, and the Earth / Circuit Protective / Ground conductors.%20

20) How long do electrical boards generally last?

Electrical boards generally have up to 10 years warranty on the parts inside and the enclosure itself. We regularly see electrical equipment in boards that are 20 years old that is still functioning. There is older equipment that is still in service and still functioning such as fuse wire fuse boxes and cartridge fuse boxes.%20

Trip switch boxes will generally be failing around the 30-year mark and in any case its best to replace them before they start to fail in this manner. When these trip switches begin to fail, they can mean several days without power as parts are sourced. Parts can be obsolete or difficult to come by and sometimes it is only second-hand parts that are available.%20

Fuse boxes will tend to burn out and fail in this manner before any other type of equipment failure occurs. Fuse boxes tend to be more simple devices and as such have fewer parts that can go wrong. Regardless of this, fuse boxes should generally be replaced in favour of trip switch style boxes these days as the latter offer far more protection but do require updating and replacing every couple of decades.%20

21) How do I know if my electrical board is bad?

There are a variety of symptoms that may indicate an electrical board is going or has gone bad. The severity of these does vary but generally, any symptom is not good and an electrician’s advice and attendance should be sought without delay.%20

• There is a buzzing noise from the electrical board
• There is noticeable heat from the board or its circuits breakers / trip switches
• There are holes in the board that you can get a finger in to (Guess don’t try it, please don’t put a finger in!)
• The cover is missing, damaged, cracked or otherwise not in accordance with the manufacturers intended design
• The enclosure / box is loose or hanging off the wall or other surface to which it is installed
• Trip switches trip regularly, don’t reset easily, or feel spongy when they are reset
• Trip switches are very stiff, GFCI or RCD / RCB test buttons do not work
• The electrical board is over 20 years old (testing is normally require to ascertain suitability of continued use)

The best way of ascertaining the suitability of your electrical board for continued use is to have an electrical inspection carried out. Wherever you are in the world, there are certain electrical tests that will be carried out by electricians to establish the safety of the electrical system. The UK has its own system which you can read more about on our website which talks about electrical inspections.

22) Do I need a new electrical board if I have a rewire?

This would almost always be the case in electrical systems, the possible exception being if the electrical board was installed within the last 5 years. Electrical safety regulations change often and this can mean that even recently installed equipment is now out of date in the eyes of the wiring regulations. When carrying out a rewire the whole system should comply with the up-to-date regulations including the electrical board but check with your electrician in your territory to confirm this is the case for your system.%20

Generally speaking, an electrical system is rewired because it is very old, has suffered extreme damage or is failing to supply the needs of the demand in the building in which it is installed. In all of these cases, a new electrical board would be required anyway.%20

23) How often should electrics be rewired?

Generally, wiring systems can last several decades depending on its use (or abuse) and any modifications that have been carried out.%20

Wiring systems that have seen little use and never been modified from new can see many years of service without requiring rewiring. In these instances, it is likely that rewiring would be carried out due to something else occurring in the property such as a new extension and a new owner that intends to live there indefinitely. It is often best to rewire an old system before installing new kitchens, bathrooms, plastering and decorating an entire home to later find that the electrical system begins to fail.%20

Where wiring systems have been subject to prolonged heavy use, they will require rewiring sooner than those that have seen little or light use. Think of a domestic property where a retired single person lives then the same house next door where a family of 6 live. You can bet that much more electricity will be required and used in the family home than that of the single person. It makes a difference. Cables heat and cool under use, components wear out, cables overheat. Constant use of electrical cabling can cause microscopic cracking in the cable insulation over time which leads to electrical current leaking to earth / ground and can begin to cause GFCI / RCD tripping.%20

Your wiring should be inspected and tested by a professional electrician every ten years as a minimum. The report that follows will detail any issues in the wiring system, the general condition, and the recommendations for improvement. You can have a conversation with your electrician about the likely need to rewire the system following this type of inspection.%20

Some wiring systems absolutely should be rewired and these tend to be very old systems. Your electrician can normally judge this from a visual inspection and recommend rewiring from there.

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