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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 · 7min · Lesson 2 of 36

Dead tests before live tests

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 · 7min
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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

Dead tests before live tests

Inspection Testing · Lesson 2 · Advanced

AdvancedReview: professional review pending

Purpose

Distinguish tests requiring a dead installation from justified live measurements and minimize exposure.

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

Continuity and insulation-resistance tests require controlled isolation; polarity has dead methods and may have a final live confirmation; Ze, Zs, prospective fault current, supply parameters and many RCD tests require energisation.

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

Core theory

Identify all sources/backfeeds, isolate, lock off, prove the indicator, prove dead at the work point and re-prove the indicator. Protect electronic equipment and control stored energy.

Before live testing, restore protective conductors and covers as far as practicable, verify dead-test results, select a suitable instrument/range, restrict access and define probe placement before exposure.

Prefer calculation or safer dead evidence where it validly meets the objective. Live work/testing still requires the legal justification and precautions; convenience is not justification.

Terms, symbols, and units
TermMeaningSymbolUnit
Dead testTest performed with relevant conductors isolated from sourcesNot applicableNot applicable
Live testMeasurement requiring energized conductorsNot applicableNot applicable
BackfeedUnexpected energisation from another supply or sourceNot applicableNot applicable
Worked exampleAn installer wants to use a live socket tester to find line/neutral reversal before completing dead polarity checks.

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

  1. Objective: Polarity topology can be established dead.
  2. Risk: Live testing needlessly energizes potentially incorrect wiring.
  3. Method: Complete dead continuity/polarity inspection first; use any later live confirmation only when justified.

Use the dead method first and do not energize unverified wiring for convenience.

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

Is a live test acceptable merely because it is faster?

No. It needs a valid objective, justification and controlled precautions.

Answer: No. It needs a valid objective, justification and controlled precautions.

Practical exercise

Classify a supplied test schedule as dead/live and add prerequisite evidence and restoration hold points.

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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