What is not covered by BS 7671?
What is not covered by BS 7671?
Out of scope for BS7671 The circuit voltage is greater than 1,000 VAC, or 1,500 VDC. The installation is related to machines (aircraft, boats, vehicles, trains, industrial equipment, lifts) Mines and quarries. Distribution of electricity, lightning conductors, electric fences.
What is the chapter in BS 7671 that gives the maximum disconnection times for a circuit?
Chapter 41
Chapter 41 Protection against electric shock 1.2). The maximum disconnection times stated in Table 41.1 now apply for final circuits up to 63 A with one or more socket-outlets and 32 A for final circuits supplying only fixed connected current-using equipment (Regulation 411.3. 2.2).
What does BS 7671 apply to?
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).
Is BS 7671 a legal document?
Although not a statutory document, BS 7671 will set the standard for how electrical installations should be completed in the UK and enables compliance with the law.
What does BS 7671 not apply to?
There are, however, many types of system, equipment and hazard to which BS 7671 is not applicable; for example, certain installations at mines and quarries, equipment on vehicles, systems for public electricity supply and explosion protection.
Which installation is exempt from the scope of BS 7671?
Installations that are excluded from BS 7671: Systems for the distribution of electricity to the public. Railway traction equipment, rolling stock and signalling equipment. Equipment of motor vehicles, except those to which the requirements of the Regulations concerning caravans or mobile units are applicable.
What is maximum disconnection time?
Maximum disconnection time for distribution circuits up to 63A is 0.4 seconds (previously this time was for circuits up to 32A). Maximum disconnection time for supplying current using equipment up to 32A is 0.4 seconds.
How do you calculate Zs?
Therefore, where reliable measured values are available for the external earth loop impedance (Ze) and for the loop resistance of the line and protective conductors (R₁ + R₂) of the circuit, it is permissible to derive the loop impedance of a circuit by using the following formula: Zs = Ze + (R₁ + R₂).
Which of the following is excluded from the scope of BS 7671?
Who would use BS 7671?
BS 7671 is British Standard “Requirements for Electrical Installations”. BS 7671 certification only applies to electrical installations, not to people. There are some qualifications – e.g. City and Guilds 2382 – which may be used to show that someone has adequate knowledge of BS 7671.
What is a fundamental principle when considering the type of wiring and method of installation?
Equipment exposed to the environment should be protected to prevent dangerous conditions. The cross-sectional area of conductors, the type of wiring and method of installation, and protective equipment should all be factors in the design with respect to both normal current loads and fault current loads.
