British StandardBS 7671"Requirements for Electrical Installations. IET Wiring Regulations", informally called in the electrical communityThe "Regs", is the national standard in theUnited Kingdomfor electrical installation and the safety ofelectrical wiringin domestic, commercial, industrial, and other buildings, also in special installations and locations, such as marinas or caravan parks and medical locations
In general, BS 7671 applies to circuits supplied at nominal voltages (Uo) up to and including 1000 volts AC or 1500 volts DC. The standard therefore covers the Extra Low Voltage (ELV) range (0-50V AC, 0-125V DC), and the Low Voltage (LV) range (50-1000V AC, 125-1500V DC). The frequencies covered for AC are 50 Hz, 60 Hz, and 400 Hz, used in the UK for houses, offices, and commerce. It did not become a recognizedBritish Standarduntil the publication of the 16th edition in 1992. The standard takes account of the technical substance of agreements reached inCENELEC.
The current version is BS 7671:2018 (the 18th Edition) issued in 2018 and came into effect from 1 January 2019.Amendment 1 to the 18th Edition was published in February 2020 but the only changes were to section 722 (Electric Vehicle Charging Installations). These changes came into immediate effect upon publication release, unlike previous amendments where 6 months elapsed before changes became compliant.BS 7671 is also used as a national standard byMauritius,St Lucia,Saint Vincent and the Grenadines,Sierra Leone,Singapore,Sri Lanka,Trinidad and Tobago,Uganda,Cyprus, and several other countries, which base their wiring regulations on
Derbyshire (/ˈdɑːrbɪˌʃɪər, -ʃər/) is a county in the East Midlands of England. A substantial portion of the Peak District National Park lies within Derbyshire, containing the southern extremity of the Pennine range of hills which extend into the north of the county. The county contains part of the National Forest, and borders on Greater Manchester to the northwest, West Yorkshire to the north, South Yorkshire to the northeast, Nottinghamshire to the east, Leicestershire to the southeast, Staffordshire to the west and southwest and Cheshire also to the west. Kinder Scout, at 636 metres (2,087 ft), is the highest point in the county, whilst Trent Meadows, where the River Trent leaves Derbyshire, is its lowest point at 27 metres (89 ft).:1 The River Derwent is the county's longest river at 66 miles (106 km), and runs roughly north to south through the county. In 2003 the Ordnance Survey placed Church Flatts Farm at Coton in the Elms (near Swadlincote) as the farthest point from the sea in Great Britain.
The city of Derby is a unitary authority area, but remains part of the ceremonial county of Derbyshire. The non-metropolitan county contains 30 towns with between 10,000 and 100,000 inhabitants. There is a large amount of sparsely populated agricultural upland: 75% of the population live in 25% of the area.