BS 7671: 2018 (2022) REQUIREMENTS FOR ELECTRICAL INSTALLATIONS Flashcards
Which regulation in BS 7671 defines the comprehensive list of installations to which it applies?
Section 514 Identification and Notices
What does a regulation ending in a “200 series number” indicate in BS 7671?
It is a regulation specific to the UK.
According to the provided information, what is the purpose of load shedding?
To reduce the impact of excessive loads during peak demand
What is the legal status of BS 7671: 2018 (2022) The IET Wiring Regulations, 18th Edition?
Non-statutory document
When was Amendment 2 of BS 7671: 2018 published, and when did it become the sole regulation?
Published in March 2022, became sole regulation in September 2022
What is the expected timeframe for the release of the 19th Edition of BS 7671?
Between 2025 and 2029
: Which chapter of BS 7671 sets out the scope of the regulations?
Chapter 11: Scope
What is the purpose of Chapter 36 in BS 7671?
To address the continuity of services, especially in emergency situations
In which chapter of BS 7671 can you find information about protection against electric shock?
Chapter 41: Protection Against Electric Shock
What is the main goal of fault protection in BS 7671?
To reduce the risk through contact with live parts during a fault
What is the purpose of the contents pages in BS 7671?
To list the topics covered in each part, chapter, or section
Which document specifies legal regulations that may be used as a tool for prosecution in a court of law if an electrical installation is not safe or suitable?
Electricity at Work Regulations (EWR)
What is the primary reason for the publication date of BS 7671 amendments being six months earlier than their implementation date?
TT
Why is additional source electrode connection necessary in PME (TN-C-S) systems?
To provide alternate paths for diverted neutral current
In a TN-S earthing system, what is typically used as the installation’s means of earthing?
Separate supplier’s earth
Which section of BS 7671 focuses on the assessment of maximum demand and diversity?
Section 311
What is the purpose of conducting an external earth fault loop impedance (Ze) measurement?
To calculate the prospective fault current (PFC)
According to BS 7671, why should every circuit be independent?
To ensure each circuit has its own line and neutral conductors
In Chapter 32 of BS 7671, what external factors are considered when deciding on the type of wiring system to install?
Environmental, such as temperature and moisture,
Utilization, such as the purpose of the installation,
Building materials, such as construction materials
What does Chapter 33 of BS 7671 primarily address?
Compatibility of electrical equipment
In Chapter 36 of BS 7671, what is the main consideration for circuits that require a continuous supply of electricity?
Using uninterrupted power supplies (UPS)
Which main risks associated with electricity are addressed in Part 4 of BS 7671?
Electric shock and overcurrent
What is the primary purpose of protection against electric shock in BS 7671?
To prevent electric shock hazards
In Part 4 of BS 7671, what does “fault protection” primarily aim to achieve?
Reducing the risk through contact with live parts during a fault
What is the primary purpose of basic protection in electrical installations?
To reduce the risk of electric shock
In BS 7671, what protective measure is the most commonly used for electrical installations to prevent electric shock?
Automatic disconnection of supply (ADS)
What is the purpose of protective earthing in electrical circuits?
To carry fault current and form part of the earth fault loop path
When should additional protection, such as an RCD, be provided in electrical circuits?
In circuits supplying socket outlets for Ordinary Persons
In a TN system, what is the purpose of the protective conductor (cpc)?
To carry fault current and connect exposed conductive parts to earth
Why are metallic enclosures required for consumer units in domestic installations?
To prevent the spread of fire in case of loose connections
In BS 7671, when should arc fault detection devices (AFDDs) be installed?
In certain residential premises with listed requirements
What are the two primary sources of overcurrent in electrical circuits?
Overload and fault current
Which protective device is commonly used to address overcurrent due to overload?
Circuit Breaker
In what situations should electrical equipment be spaced from stored or manufactured combustible material?
In locations with a fire risk due to stored or manufactured material
What is the primary purpose of arc fault detection devices (AFDDs) in electrical circuits?
To detect variations in the current sine wave
In BS 7671, what is the standard distance above which live parts are considered out of reach in controlled or supervised installations?
2.5 meters
What is the primary role of obstacles as a means of basic protection in electrical installations?
To prevent intentional contact with live parts
In electrical installations, what does the IPXXB rating for holes in enclosures mean?
Holes up to 12 mm in diameter are allowed
What is the primary purpose of placing electrical equipment out of reach in controlled or supervised installations?
To prevent accidental contact with live parts
In electrical installations, what is the primary purpose of a residual current device (RCD)?
To detect and disconnect in the event of a fault current to earth
What is the purpose of supplementary equipotential bonding in electrical installations?
To ensure equal voltages exist between equipment under fault and extraneous parts
In BS 7671, what type of equipment is permitted for double or reinforced insulation?
Class II equipment
What is the primary purpose of electrical separation in electrical circuits?
To create an independent circuit unaffected by earth
In electrical installations, what is the purpose of separated extra-low voltage (SELV) and protective extra-low voltage (PELV) systems?
To provide basic insulation
What does the value of earth fault loop impedance (Zs) indicate in an electrical installation?
The suitability of the circuit’s protective devices
In TT systems, what is the primary reason for using residual current devices (RCDs)?
To provide protection against electric shock
When is it necessary to use an RCD with a rated current not exceeding 30 mA in electrical installations?
In circuits supplying luminaires within domestic installations
What is the primary purpose of protective equipotential bonding in electrical installations?
To connect metal gas or water pipes to the earth
Which section of BS 7671 provides requirements for automatic disconnection of supply (ADS)?
Section 411
What is the purpose of the protective equipotential bonding conductor complying with Chapter 54 in electrical installations?
To connect extraneous conductive parts to the earth
In BS 7671, what are the required disconnection times for final circuits with a rated current not exceeding 63 A and a nominal voltage to earth of 230 V in a TT system?
0.4 seconds
When should additional protection by means of a residual current device (RCD) be provided in socket outlets?
In socket outlets with a rating up to 32 A with restricted use
In BS 7671, what is the purpose of Class II equipment?
To provide basic protection
What is the primary purpose of the IPXXD rating for accessible top surfaces of enclosures?
To prevent objects measuring 1 mm in diameter and 100 mm long from entering
Which of the following is NOT an overcurrent protective device?
Lighting rods
What is the purpose of a fuse in an electrical circuit?
To interrupt the circuit when current exceeds a certain level
What is NOT a characteristic of a rewirable fuse (BS 3036)?
High breaking capacity
What is the purpose of the breaking capacity (kA) rating for a fuse?
To specify the maximum fault current the fuse can safely disconnect
Which type of fuse is generally used for high prospective fault currents and comes in gG and gM categories?
BS 88 fuse
What is the primary function of miniature circuit breakers (MCBs)?
To provide protection against overloads
Which type of MCB is suitable for circuits with inrush currents, such as those with small to medium motors?
Type C MCB