18th Edition of the wiring regs



The 18th edition of B.S.7671  Requirements for electrical installations, IET wiring regulations, was launched in June of 2018. The requirements come into effect for all work designed and installed after 1st January 2019. The three biggest changes are;

1) the use of Arc Fault Detection Devices (AFDD’s). This recommendation is to mitigate the risk of fire in an electrical circuit from arc fault currents. Arc fault detection devices have been around for some time and are used extensively in countries like the United States and Germany. However, in the United Kingdom designers are now asked to consider installing these devices. Presently, AFDD’s are quite bulky, typically, the size of two or three circuit breakers. This will mean therefore that the size of distribution boards will have to be much bigger to accommodate the AFDD’s. The onus is now on manufacturers to design AFDD’s to make them more compact and affordable.

2) The Use of Surge Protection Devices (SPD’s).  While this recommendation was put in the previous edition of the wiring regulations, it has now been given more emphasis. Regulation 443.4 says that SPD’s must be installed where over-voltage spikes caused by switching or of atmospheric origin (lightning), would result in serious injury to, or loss of human life. Result in disruption to public services. Result in interruption to commercial or industrial activity. Affect a large number of co-located individuals. All other cases must have a risk assessment to determine if protection by use of an SPD is required.

3) Where in the 3rd amendment of the 17th edition of the wiring regulations it was mandatory to secure wiring systems using metal ties and fixings on all escape routes, so that in the event of fire, the fixings would not melt and cause the wiring system to drop and hang, causing a hazard to any fire fighting crews. This has now been upgraded to cover the whole installation in a building.

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