Apprentice Training Hub
NVQ Level 3, AM2 & BS 7671:2018+A3:2024 Knowledge Base
Required Test Sequence
Always Isolate Before TestingQuick Reference Data
BS 7671 Limits & Parameters- 6A Type B MCB 5.82 Ω
- 32A Type B MCB 1.09 Ω
- 40A Type B MCB 0.87 Ω
- 0.5 × IΔn (15mA) No Trip (>1999ms)
- 1.0 × IΔn (30mA) ≤ 300 ms
- 5.0 × IΔn (150mA) ≤ 40 ms
- SELV / PELV (≤ 50V) ≥ 0.5 MΩ
- Low Voltage (≤ 500V) ≥ 1.0 MΩ
- Over 500V ≥ 1.0 MΩ
- Final Circuits (≤ 63A Sockets) 0.4 s
- Distribution / Fixed Eq. (> 32A) 5.0 s
- TT System (230V) 0.2 s
C&G 2391 / AM2 Knowledge Quiz
460 Questions • 70% Pass MarkBeginner Modules
Visual Inspection
20 questions
Polarity Testing
20 questions
Functional Testing
20 questions
Safe Isolation Procedure
Interactive Simulator
Intermediate Modules
Continuity Testing
20 questions
Insulation Resistance
20 questions
Prospective Fault Current
20 questions
Advanced Modules
Earth Fault Loop Impedance
20 questions
RCD Testing
20 questions
Fault Finding Diagnostics
Scenario Simulator
On-Site Essentials
Field Guides & DocumentationCommon Questions
20 plain-English regulation answers covering frequently asked site queries.
EICR Coding Guide
Breakdowns of Code C1, C2, C3, and FI observations with real-world examples.
Compliance Checklists
Step-by-step verification lists for New Installs, CU Changes, EV, and PV.
RAMS Generator
Generate professional, site-specific Risk Assessments and Method Statements instantly.
BS 7671:2018+A3:2024 Inspection & Testing Guide
Mastering the statutory inspection and testing procedures is the most critical hurdle for any electrical apprentice working towards their NVQ Level 3, AM2, or City & Guilds 2391 qualifications. This TMUK Group training hub provides a centralized knowledge base to reinforce your understanding of the IET Wiring Regulations.
The Golden Rule: Dead Before Live
You must never energise a new or altered circuit without first proving it is safe to do so. The sequence of testing is dictated by BS 7671 Guidance Note 3 to ensure safety at all times:
- Dead Testing: Carried out with the supply completely isolated and locked off. This includes verifying the continuity of your circuit protective conductors (CPCs) and ring finals, checking insulation resistance (IR) to ensure no shorts exist, and verifying correct polarity.
- Live Testing: Only commenced once dead tests confirm the installation is safe to energise. This phase verifies Earth Fault Loop Impedance (Zs/Ze), Prospective Fault Current (PFC), and the mechanical trip times of RCDs/RCBOs.
EICR Coding & Quick Reference
When carrying out an Electrical Installation Condition Report (EICR), inspectors must classify deviations from BS 7671 using standard codes. Memorise the critical thresholds provided in our Quick Reference grid, such as maximum Zs limits (temperature-adjusted to 80%) and RCD trip times, to accurately assign C1 (Danger Present), C2 (Potentially Dangerous), or C3 (Improvement Recommended) codes.