Paul Dawson from electrical accessories and consumables specialist, Niglon, discusses circuit protection and the impact of the 18th edition wiring regulations on specification choices and future product development trends.
Circuit protection has been recognised as an important element of electrical safety through several iterations of the wiring regulations, with a clear focus on ensuring the risk of fire, electrical shocks and damage to electrical appliances is minimised for all electrical installations.
Following the distressing events at Grenfell Tower last year, electrical safety has never been higher on the political agenda or more prominent in public consciousness. Unsurprisingly, therefore, the level of safety and risk management offered by circuit protection devices has come under increased scrutiny and additional requirements have been included in the latest wiring regulations. However, there are some grey areas surrounding what’s mandatory and what’s discretionary in the new rules, so it’s important to understand them in detail.
One key focus for circuit protection in the 18th edition is surge protection to reduce the risks to buildings and their occupants associated with transient voltages. To address this, the 18th edition stipulates that installers should assess whether there is a serious risk of injury or loss of life from electrical surges caused by transient voltages and install SPDs if the risk is considered high.
The new regulations do not make installation of SPDs mandatory, but that doesn’t mean the guidance can simply be overlooked. A close reading of the 18th edition highlights that including SPDs in the specification is much more than an advisory. Installers must carry out a comprehensive risk assessment if they decide not to install SPDs. This includes a calculation that requires knowledge of the length of the cables entering the building from overhead lines, from underground networks and from the final electricity supply point. It is likely that this information will only be available from the relevant utility company, which will probably involve applying for the figures and waiting for a response. It may even incur an administration fee.
Indeed, the stipulations for the risk assessment and information required to side-step installation of an SPD are so wide-ranging and time-consuming that installing an SPD is by far the less onerous option.
Of course, installation of SPDs is already considered a best practice approach to electrical safety by many, and the devices themselves are nothing new. Niglon has offered a popular range of SPDs for several years as part of our wide-ranging circuit protection portfolio. The difference now is that a comprehensive risk assessment must be carried out if an SPD is not included in the spec. Even for commercial premises, where the cost of multiple SPDs may have more impact than it would for the domestic electrical install sector, the increased complexity of the risk assessment and mandatory documentation is prohibitive.
Arc Fault Detection
The other major talking point when it comes to circuit protection guidance in the 18th Edition is the recommendation that an AFDD (arc fault detection device) should be installed as a means of providing additional protection against fire caused by arc faults. The key word in that sentence is ‘recommendation’, however, and it’s important to note that there is no mandatory requirement to install an AFDD in the new wiring regulations, nor any compulsory risk assessment.
It’s vital to clarify this point because, even in the short space of time since the 18th Edition was published, there has been a degree of panic and scaremongering about the implications of incorporating AFDDs in every new installation. The size and cost of AFDD units in comparison to standard circuit protection devices means that this would be an extremely onerous requirement, which may be why the regulations have recommended this measure, rather than requiring this change.
Though a risk assessment for AFDDs has not been stipulated by the updated wiring regulations, the decisions about whether or not to follow this recommendation should be taken on a project by project basis, aligned to the level of risk for a particular environment. For example, buildings that are more difficult to evacuate, such as hospitals and care homes, carry a greater risk to life from an electrical fire. Sites where some areas are unmanned and a fire may go undetected for longer should also be considered higher risk.
This area of circuit protection guidance has been introduced to the wiring regulations specifically to reduce electrical fire safety risk but we must remain mindful that existing circuit protection requirements and electrical standards already provide a high level of safety. In fact, the AFDD guidance in the 18th Edition can be seen as an indication to electrical suppliers that AFDDs may become mandatory at some point in the future so contractors can expect to see AFDD technology develop, with the advent of smaller and less expensive units over the next few years.