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Educational use: ElectraCore supports learning and preliminary checks. It does not replace a competent electrician or engineer. Verify results, equipment data, and current local regulations before installation or live work.
Courses/Inspection & Testing/Test Sequence & Preparation

lesson · 8min · Lesson 1 of 36

Why test sequence matters: safety

Course syllabusCourse overview
01Test Sequence & Preparation
  1. ReadWhy test sequence matters: safety
  2. ReadDead tests before live tests
  3. ReadTest instrument calibration and leads
  4. ReadBS 7671 Appendix 6 test schedule
  5. quizPreparation quiz
02Continuity Testing
  1. ReadRing final continuity: three tests explained
  2. ReadProtective conductor continuity
  3. ReadMain and supplementary bonding continuity
  4. ReadContinuity test results: limits and recording
  5. exerciseContinuity exercise
03Insulation Resistance
  1. ReadIR testing principles: 500V, 1000V
  2. ReadTesting between live conductors and earth
  3. ReadLow IR readings: causes and diagnosis
  4. ReadElectronic equipment and IR testing
  5. quizIR testing quiz
04Earth Fault Loop Impedance
  1. ReadExternal impedance Ze measurement
  2. ReadTotal loop impedance Zs measurement
  3. ReadComparing Zs to Table 41.1 limits
  4. ReadCorrecting excessive Zs readings
  5. exerciseZs measurement exercise
05RCD Testing
  1. ReadRCD tripping current tests: half-rated and rated
  2. ReadRCD trip time testing at 1× and 5× rated current
  3. ReadMaximum trip time limits for different RCD types
  4. ReadRecording RCD test results
  5. quizRCD testing quiz
06Polarity & PFC
  1. ReadPolarity testing: dead and live methods
  2. ReadPFC measurement at origin and boards
  3. ReadVerifying PFC against device ratings
  4. quizPolarity and PFC quiz
07Certification & EICRs
  1. ReadEIC: Electrical Installation Certificate
  2. ReadMinor Works Certificate: when to use
  3. ReadEICR: periodic inspection
  4. ReadObservation codes C1, C2, C3, FI
  5. exerciseEICR coding exercise
08Final Assessment
  1. exerciseFull mock test schedule: complete it
  2. quizFinal written assessment
Lesson · 8min
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In this lesson

PurposeCore theoryWorked exampleKnowledge checkSources

In this lesson

PurposeCore theoryWorked exampleKnowledge checkSources
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ElectraCore lesson handout

Why test sequence matters: safety

Inspection Testing · Lesson 1 · Advanced

AdvancedReview: professional review pending

Purpose

Plan test sequence so each result establishes safety prerequisites for the next stage.

Before you beginSafe isolation · Protective conductors and circuit topology

Learning objectives

  • Plan a defensible sequence
  • Verify instrument and test boundary
  • Interpret topology from patterns
  • Record evidence without invented limits

BS 7671's verification sequence starts with inspection and dead tests because continuity, polarity, separation and insulation defects should be found before energisation. Sequence is a safety dependency, not a mnemonic contest.

SAFE TEST SEQUENCE AND EVIDENCESAFE TEST SEQUENCE AND EVIDENCEORIGINCIRCUITtest pointinspect · isolate · prove · measure · interpret · restore · record

Core theory

Define work type, applicable edition, supply/earthing, extent, drawings, protective measures, special installations and who controls isolation before testing.

Complete relevant inspection and dead tests, resolve dangerous anomalies, restore connections, then perform only justified live tests under a risk assessment and controlled access.

A competent person may vary sequence where necessary, but must avoid danger and record reasons, limitations, omissions and alternative evidence. Never mark an unperformed test as satisfactory.

Terms, symbols, and units
TermMeaningSymbolUnit
Initial verificationInspection and testing of new or altered work before serviceNot applicableNot applicable
LimitationAgreed restriction on the extent of inspection or testingNot applicableNot applicable
Test dependencyEarlier evidence required to make a later test safe/meaningfulNot applicableNot applicable
Worked exampleProtective-conductor continuity fails on a new circuit, but the tester proposes live Zs next.

Assumptions: Values are supplied test data; The installation is safely isolated for dead testing.

  1. Stop: The fault path is unproved.
  2. Diagnose: Keep isolated and locate/correct the continuity defect.
  3. Resume: Repeat affected dead tests, restore the system, then reconsider live tests under the plan.

Do not energize for Zs; correct and re-verify the protective path first.

Reasonableness check: The conclusion uses expected topology and comparative patterns; no single convenient reading overrides inspection or missing evidence.

Common mistakes
  • Starting live tests before dead-test defects are resolved
  • Calling a calibration label a pre-use functional check
  • Declaring a universal maximum continuity value without design context

Where this appears in practice

Initial verification combines inspection and ordered tests to prove protective measures before energisation; periodic work records the extent, limitations and observed condition.

SafetyTesting can create exposed conductors, remove protective paths or inject hazardous test voltage. Isolate and lock off, prove dead, control the area, discharge capacitance, reconnect every protective conductor and never leave a test link or bonding conductor removed.
Local code checkUse the edition of BS 7671 applicable to the work (noting the 2026 transition), current Guidance Note 3, the correct Appendix 6/model form, instrument manufacturer instructions, GS38, Electricity at Work Regulations and site safe system. Sequence may be varied only by competent risk-based planning with omitted/not-applicable tests and limitations explicitly justified and recorded.

Knowledge check

Can a failed dead test be ignored because a later live test may pass?

No. Resolve the defect and repeat dependent verification before energisation.

Answer: No. Resolve the defect and repeat dependent verification before energisation.

Practical exercise

Create a test dependency graph and safe hold points for a supplied new installation.

Summary

  • Inspect and dead-test before avoidable live testing
  • Instrument validity has several independent checks
  • Continuity patterns prove topology and support later calculations

Sources and review

  • BS 7671 and Guidance Note 3: Inspection & Testing: IET; BS 7671:2018+A4:2026 / GN3 10th edition; transition rules apply; United Kingdom
  • Model forms for BS 7671: IET; A4:2026 and earlier applicable editions; United Kingdom
  • GS38: Electrical test equipment for low-voltage systems: HSE; Fourth edition; Great Britain
  • Ring-final continuity Step 3 resistance readings: IET Wiring Matters; 2022; United Kingdom

Editorial review date: 2026-08-22. Professional electrical review is pending.

Educational material for learning and preliminary checks. Verify current local requirements and exact equipment instructions. This lesson does not replace competent professional work.

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