Editing Distribution board (section)

==== Examples ====
In the UK, consumer units (CU) have evolved from basic main switch and rewireable fuses, that afforded only overload and short circuit protection, into sophisticated control units housing many safety features that can protect against different types of electrical fault. The choice of circuit protective device will depend upon the type of electrical circuit it is protecting and what level of protection needs to be afforded. BS7671:2018 Requirements for Electrical Installations, also referred to as the IET Wiring Regulations, gets regularly updated and its latest edition at the time of writing is amendment 2:2022 released on 28 March 2022.
Typical configurations of CU:
* Main switch consumer unit - Consists of a main switch that will disconnect power to all circuits simultaneously which has one busbar linking all protective devices to a common live source, and one neutral conductor or link bar connecting to a common neutral rail. There will be a separate earth rail to allow the main earth conductor to be connected. This example offers the highest degree of circuit separation as all circuits are independent. This particular example amay not be suitable as a standalone solution with only overload and short circuit protection [[circuit breaker|MCBs]] for each circuit. Additional protection from earth leakage [[residual-current device#RCBO|RCBOs]] faults and arc faults [[AFDD]] may be required by BS7671 making this an expensive solution.
* Main Switch and Dual RCD consumer unit - Consists of a main switch that will disconnect power to all circuits simultaneously and two 30mA RCDs [[residual-current device|RCDs]] each with its own live busbar each protecting a separate bank of circuits, typically half-and-half but other combinations are available, from earth leakage faults. Offers a cost-effective solution by using a combination of cheaper mcbs and only two, more expensive, RCDs. 
* High integrity consumer unit - Consists of a main switch that will disconnect power to all circuits simultaneously and three separate live busbars, one linked directly to the main switch and two others on each main RCD. The live busbar on the main switch allows the use of mcbs only where more sensitive devices such as RCBOs and AFDDs would not be appropriate, or the independent use of RCBOs, and may be limited to only one or two ways. The remainder of the circuits are divided in the same way as a dual RCD CU. This type of consumer unit offers improved circuit separation over a dual RCD CU whilst allowing for more flexibility.
* RCD incomer consumer unit - This is the least convenient solution in terms of circuit separation because the main switch is an RCD. Less common than the other types, it is no longer considered a standalone solution because power to all circuits is lost in the event of an earth fault causing the main switch RCD to activate.

Modern consumer units are now required to be metal (non-combustible) and usually use [[DIN rail]] mounted devices. The DIN rail is standardized but the [[busbar]] arrangements are not. Mixing of different brands devices is against the manufacturers requirements and should generally be avoided.

The choice of consumer unit will reflect several factors such as the size and layout of the dwelling, number of floors, outbuildings, the expected loads (lighting, sockets, ovens, showers, immersion heaters, car-chargers etc.), and how much protection is required for each circuit.

The box pictured top-right is a "Wylex standard" fitted with rewirable fuses. These boxes can also be fitted with cartridge fuses or miniature [[circuit breaker]]s (MCBs). This type of consumer unit was very popular in [[United Kingdom|Britain]] until 2001 when wiring regulations mandated [[residual-current device]] (RCD) protection for sockets that could "reasonably be expected to" supply outdoor equipment ([[BS 7671]]:2001, {{ISBN|0-86341-373-0}}). There were a number of similar designs from other manufacturers but the Wylex ones are by far the most commonly encountered and the only ones for which fuseholders/breakers are still commonly available.<ref>{{cite web|title=Google search on UK availability of Modern breakers for older consumer units|url=http://www.screwfix.com/p/wylex-32a-sp-type-b-curve-mcb/87979|publisher=Screwfix|access-date=5 March 2016}}</ref>

Some manufacturers have added innovative features such as [[CPN Cudis]] who have added a [[LED]] strip light to their 'Lumo' consumer unit to enhance visibility in dark locations such as under staircases.<ref>{{cite web|title=Innovative Bury company recognised with three award nominations|url=http://www.burytimes.co.uk/news/business/11608891.Innovative_Bury_company_recognised_with_three_award_nominations/|website=www.burytimes.co.uk|access-date=6 May 2015}}</ref>