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18th Edition · Electrical revision

Electrical — 18th Edition revision notes

BS 7671: shock protection and ADS, earthing and bonding, overcurrent and RCDs, cable selection, inspection and testing, special locations and safe isolation.

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  • 8notes, free to read
  • 315questions; 25 free to try
  • 8topics

Principles & definitions

  1. BS 7671 Status, Voltage Bands and Key DefinitionsHow BS 7671 fits with UK law, the ELV and LV voltage bands, SELV, PELV and FELV, and the core definitions used throughout the Wiring Regulations.

Protection against electric shock

  1. Protection Against Electric Shock: ADS, Disconnection Times and RCDsHow automatic disconnection of supply protects against electric shock, the maximum disconnection times, and the roles of the 30 mA RCD and SELV.

Earthing & protective bonding

  1. Earthing systems and protective bondingHow TN-S, TN-C-S (PME) and TT systems earth an installation, and why we bond extraneous-conductive-parts.

Overcurrent, RCDs & devices

  1. Overcurrent protection, RCDs and devicesOverload versus fault current, the Ib <= In <= Iz rule, MCB tripping curves, breaking capacity and RCD types.

Selection & erection: cables

  1. Selection and Erection of Cables: Ratings, Colours and Concealed-Cable ProtectionHow to identify conductors and coordinate a cable with its protective device, including derating, voltage drop, insulation temperatures, IP ratings and concealed-cable protection.

Inspection & testing

  1. Inspection and Testing: Initial Verification, Dead and Live Tests, CertificatesThe order and purpose of initial verification, the dead and live test sequences, and which certificate or EICR code applies.

Special locations

  1. Locations Containing a Bath or Shower: Zones and Protection (Section 701)Section 701 rules for rooms containing a bath or shower: the zones, 30 mA RCDs, IP ratings, SELV limits and when supplementary bonding may be omitted.

Safe isolation

  1. Safe Isolation: Proving a Circuit Dead under the EAWR 1989Safe isolation under the Electricity at Work Regulations 1989 using the GS38 prove-test-prove method and suitable test instruments.

Use 18th Edition practice to explain the selection

For 18th Edition exam revision, identify the installation conditions before selecting a protective measure or applying a requirement. Explain how the question’s circuit, environment and equipment affect the choice. Reading a familiar regulation number is different from applying it to a scenario.

Use the notes alongside the edition and amendment specified by your assessment centre. Inspection and testing revision develops the verification topics further, while the electrical safety notes revisit isolation and the plumbing-work boundary.

More Electrical modules

Every module has its own revision notes and question bank.

Inspection & Testing