Dead Tests Continuity Testing

Page 1

  • Key Focus Areas:

    • Continuity of conductors

    • Continuity of Main Earthing Conductor

    • Dead Tests: Continuity Testing

    • Inspection and Testing

Page 2

  • Resistance Values for Cables:

    • Reference: Table B1 of Guidance Note 3

    • Expected resistance values for copper conductors

    • Importance for verifying test results

    • Typical single-phase installation example:

      • Earthing conductor (16 mm²)

      • Main Protective Bonding Conductors (10 mm²) connected to gas and water service pipes

Page 3

  • Continuity of Main Protective Bonding Conductors Test:

    • Purpose: Ensure conductors are continuous with no breaks

    • Low-resistance ohmmeter used

    • Preparation involves disconnecting bonding conductor at the MET

    • Health and Safety:

      • Ensure installation is isolated before bonding removal

      • Risks of disconnecting bonding: potential electric shock due to voltage differences

Page 4

  • Testing Method:

    • Test conductor resistance end-to-end

    • Use IET On-Site Guide or GN3 for expected resistance values

    • Calculate resistance for a conductor using: R = (mΩ/m) x (length in m)

    • Bonding issues: parallel paths can affect resistance measurement

Page 5

  • Continuity of cpc for Radial Circuits:

    • Purpose: Confirm cpc connection throughout the circuit

    • Equipment: Low-resistance ohmmeter

    • Two methods: R1 + R2 and R2

    • Health and Safety: Circuit must be isolated

    • Testing involves ensuring no parallel paths interfere

Page 6

  • Recording Results:

    • Highest reading during tests recorded in the schedule

    • Use R1 + R2 for future fault impedance tests

    • Importance of R1 + R2 values as benchmarks for circuit health

Page 7

  • Continuity Testing Example:

    • Figure 6.28: Testing at light switch using R1 + R2 method

Page 8

  • Testing Continuity of Ring-Final Circuits:

    • Purpose: Ensure ring is wired correctly with no breaks

    • Steps for conducting tests, including interconnections for figure 8 setup

    • Importance of isolating circuit before testing

Page 9

  • Expected Results for Ring Testing:

    • Results dependent on conductor size and loop length

    • Recordings for each step with a focus on consistency across outlets

Page 10

  • Conclusion of Testing:

    • Verify consistency of results before concluding the circuit is correct

    • Importance of documenting all readings for fault tracing

    • Recommended practice: Create a reading schedule for better analysis of results.