18th Edition Mythbuster

Recommendations

Info

www.cudis.co.uk Introduction <strong>18th</strong> <strong>Edition</strong> of the IET Wiring Regulations (BS7671:2018 Requirements for Electrical Installations) is now fully effective and installations designed after January 1st 2019 must comply with these requirements. The Regulations apply to the design, erection and verification of electrical installations, also additions and alterations to existing installations. In this guide we provide an overview of some of the changes including those regarding surge protection and RCD types. This information provided is no substitute for the BS7671:2018 regulations and designers & installers should follow the requirements & recommendations within the regulations. Low Voltage Assemblies (421.1.201) There has been no change in this regulation or any other regulation which results in the way consumer units and distribution boards are constructed. Within domestic/household premises, consumer units and similar switchgear assemblies shall comply with BS EN 61439-3 (effective January 2016) and shall have their enclosure manufactured from non-combustible material or be enclosed in a cabinet or enclosure constructed of a non-combustible material. Integration of Devices and Components (536.4.203) In low voltage assemblies e.g. consumer units/distribution boards and incorporated devices/components shall only be declared suitable according to the manufacturer of the assembly. Essentially this means that you must use the board manufacturer’s approved control devices (MCBs, RCDs, etc). So, typically, the board and it’s component devices will come from the same manufacturer. Cudis only declare Cudis devices to be suitable for it’s boards. If a deviation from assembly manufacturer’s instructions is introduced then the person introducing the deviation becomes the manufacturer and takes on the corresponding obligations. Additional Requirements for Socket Outlets (411.3.3) Additional protection by use of a 30mA RCD is now required for all socket outlets with ratings up to and including 32A and all domestic lighting circuits. Without exception, every socket outlet in a dwelling must have RCD protection. If the installation is not a dwelling and if RCD protection may not be desirable for certain applications (such as supply to a computer server), a documented risk assessment will be required to determine that RCD protection is not necessary. 2
www.cudis.co.uk Caravan Parks (708.415.1) Every socket outlet and also a final circuit intended for the fixed connection (from the connection/metering point to the consumer) of a supply to a mobile or residential park home shall be both individually protected by an RCD having a rated residual operating current not exceeding 30mA. Devices selected shall disconnect all live conductors. Arc Fault Detection Devices (421.1.7) The use of Arc Fault Detection Devices (AFDDs) conforming to BS EN62606 is a recommended method for providing additional protection against fire caused by arc faults in AC final circuits. This device is specifically to detect and disconnect dangerous electrical arcs in both the fixed wiring and the connected equipment which could be the source of a fire. If used, AFDDs should be installed in consumer units/ distribution boards at the origin of the circuit to be protected. Following are examples of when additional AFDD protection may be want to be considered: - Premises with sleeping accommodation - Locations with a risk of fire due to the nature of processed or stored materials (i.e. BE2 locations such as barns, wood-working shops, stores of combustible materials) - Locations with combustible construction materials (i.e. CA2 locations such as wooden buildings) - Fire propagating structures (i.e. CB2 locations) - Locations with endangering of irreplaceable goods In the schedule of inspections, under the section dealing with consumer units and distribution boards there is a reference to check for the AFDD six monthly test notice, similar to what is already common practice for RCDs and RCBOs. Although the use of AFDDs is not mandatory, at this time, Cudis are currently developing compact AFDD devices which should become available during 2019. Overvoltage Control (443.4) Protection against transient overvoltages is now required in a number of specified situations where overvoltage could result in: - Serious injury or loss of life - Interrupted public services - Damage to cultural heritage - Interrupted industrial and commercial activity - Affect a large number of co-located individuals or - In any building which has lightning protection system installed or is supplied via overhead lines. For other circumstances a risk assessment must be carried out to determine if protection against transient overvoltage is required. Designers should note that if they do not do a risk assessment, protection against transient overvoltage must be provided. The only exception is for individual dwellings if the total value of the electrical installation and electrical equipment therein fails does not justify such protection. 3
Page 1: GUIDE TO THE NEW 18 TH EDITION WIRI
Page 5 and 6: www.cudis.co.uk Unwanted Tripping (
Page 7 and 8: www.cudis.co.uk Can I use another b

18th Edition Mythbuster

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?