This practical guide shows you how to complete a signed, QR-verified Loop Impedance (Zs) & Breaker Validation Calculator certificate in OhmCert Module #02 and how to troubleshoot non-compliant readings on site.

1. Step-by-Step OhmCert UI Workflow

  1. Open Module #02: Navigate to Loop Impedance (Zs) & Breaker Validation Calculator from the Dashboard.
  2. Load a 1-Click Standard Annex Preset: Open the blue Standard Annex banner at the top and click a preset (such as "B16 MCB Final Socket/Lighting (In=16A, Im=80A, 2.5mm2 PVC)") to populate target limits automatically.
  3. Enter Your Field Measurements: Fill in the measured inputs (Nominal Line-to-Earth Voltage Uo, Earthing System Arrangement (IEC 60364-4-41), Measured Loop Impedance Zs (or Ra in TT), Magnetic / Instantaneous Trip Setting Im, Nominal Current In, RCD Residual Operating Current IΔn, Fault Disconnection Time t (IEC 60364-4-41 Table 41.1), PE Conductor Cross-Section S_PE, PE Conductor Insulation (IEC 60364-5-54 k factor), Circuit ID). Blank inputs stay neutral PENDING.
  4. Complete the 12-Point Checklist: Grade each item, attach photos if needed, and export the SHA-256 signed PDF certificate.

2. Worked Numerical Field Case Study

Scenario: B16 MCB Final Socket/Lighting (In=16A, Im=80A, 2.5mm2 PVC) (EN 60898 Type B) — Type B 16 A MCB (Im = 5 x In = 80 A), TN-S, 30 mA RCD, 2.5 mm2 PVC PE conductor..

  • Nominal Line-to-Earth Voltage Uo: 230 V
  • Earthing System Arrangement (IEC 60364-4-41): TN-S
  • Nominal Current In: 16 A
  • Magnetic / Instantaneous Trip Setting Im: 80 A
  • RCD Residual Operating Current IΔn: 30 mA
  • Fault Disconnection Time t (IEC 60364-4-41 Table 41.1): 0.4 s (Final circuit <= 63 A)
  • PE Conductor Cross-Section S_PE: 2.5 mm2
  • PE Conductor Insulation (IEC 60364-5-54 k factor): PVC (k = 115)

3. Engineering Troubleshooting: Corrective Actions When a Reading Fails

  1. Install a 30 mA or 100 mA Residual Current Device (RCD / RCBO) so disconnection relies on I_delta_n rather than high magnetic fault current Im.
  2. Change a Type D or Type C MCB to Type B if load inrush current permits (halving or quartering required Im).
  3. Run a supplementary parallel Protective Earth (CPC) conductor or upsize the circuit cable cross-section to reduce (R1 + R2).

→ Try This Worked Example Live in Module #02 (Loop Impedance Zs)