satisfying competence requirements should be qualifi cation as an electrician with up-to-date knowledge of requirements in BS 7671:2018 but also with specifi c knowledge of the requirements given in Section 722 Electric Vehicle Charging Installations. This type of installation is one of the special installations or locations given in Part 7 of BS 7671:2018. However, section 722 requirements have recently been amended with the publication of Amendment 1:2020 to BS 7671:2018.


By Bob Cairney I Eng MIET Technical Standards Adviser, SELECT


T


he Scottish Government’s plans for de-carbonisation of the environment are intended to help cut the levels of carbon in the atmosphere and reduce air pollution in our cities.


However, these measures are also providing opportunities for enterprising electrical contracting businesses who may be looking to diversify into new areas of work. The announcement to end sales of new petrol and diesel cars and vans by 2032 is one particular area which may interest these businesses. Such a move will require signifi cant investment to provide a charging infrastructure throughout Scotland to power the electric vehicle (EV) revolution currently gathering pace as we move forward into the decade ahead. Those who possess the necessary


knowledge and skills should be well placed and much in demand to become involved with this – however, appropriate training will be necessary. This will also help such businesses to satisfy current industry competence requirements and enable installers to become ‘approved installers’ which is a requirement to access government incentives on behalf of customers, e.g. the Offi ce for Low Emission Vehicles (OLEV) home charge scheme, which provides up to £500 of grant funding for such installations. As a minimum, the starting point to


When does A1:2020 come into eff ect?


Amendment 1:2020 does not need to be implemented until after 31 July 2020. However, it can be used immediately from its date of publication in February 2020, therefore it is recommended that if undertaking such work, you should have access to the document and be familiar with its content. A brief overview of some of the amended requirements is provided below for guidance.


New symbols New symbols are included in the list of symbols given in Part 2 of BS 7671:2018 including a symbol for Cmax Cmax


. is defi ned as the maximum


voltage factor to take account of voltage variations depending on time and place, changing of transformer taps and other considerations and for a low voltage supply given in accordance with the ESQCR is given the value of 1.1. This is used in the calculation of load balance and earth electrode resistance and makes an adjustment for the worst conditions of fault current that may exist during a fault which would be 253 V for a supply given with a nominal voltage of 230 V.


Load curtailment When determining the maximum demand of an installation, load


Amendment 1:2020 is currently published as a standalone document and is available free to view on the IET website at www.electrical.theiet.org/ bs-7671/updates/


An amendment to BS 7671 covering EV installation has recently been published


curtailment, including load reduction or disconnection, either automatically or manually, may now be taken into accou nt. Load curtailment is similar to load shedding, where electrical loads are switched off for variable periods of time to optimise demand.


PME earthing facility Regulation 722.411.4.1 now requires that a PME earthing facility shall not be used when charging outdoors unless one of the fi ve methods given is used. These are basically as follows: i. A balanced three-phase installation ii. The main earthing terminal of the installation is connected to an additional earth electrode iii. A device which electrically disconnects line, neutral and protective earth connections, when the supply voltage is greater than 70 V between the protective conductor and earth iv. A device which electrically disconnects line, neutral and protective earth connections, when the supply voltage is greater than


Continued on page 28 >>> CABLEtalk APRIL/MAY 2020 27


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