This practical guide shows you how to complete a signed, QR-verified Cable Ampacity (Ib <= In <= Iz) & Voltage Drop (%ΔU) Verification certificate in OhmCert Module #31 and how to troubleshoot non-compliant readings on site.

1. Step-by-Step OhmCert UI Workflow

  1. Open Module #31: Navigate to Cable Ampacity (Ib <= In <= Iz) & Voltage Drop (%ΔU) Verification 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 "3-Phase 400 V MCC Feeder: 1x (4x70 mm2) Cu XLPE on Perforated Tray (85 m, 160 A MCCB)") to populate target limits automatically.
  3. Enter Your Field Measurements: Fill in the measured inputs (Circuit Supply System, Nominal Line-to-Earth Voltage Uo, Conductor Material, Conductor Insulation Thermal Rating, IEC 60364-5-52 Reference Installation Method, Conductor Cross-Section S, Parallel Cables per Phase, Design Load Current Ib, Protective Breaker / Fuse Nominal Current In, One-Way Cable Route Length L, Load Power Factor cos(phi), Ambient Air / Ground Temperature T_amb, Circuit Grouping Derating Factor Cg (Table B.52.17), IEC 60364-5-52 Annex G Voltage Drop Limit Category). 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: 3-Phase 400 V MCC Feeder: 1x (4x70 mm2) Cu XLPE on Perforated Tray (85 m, 160 A MCCB) (IEC 60364-5-52 Method E) — Industrial sub-main feeder at 35°C ambient and Cg=0.85 grouping..

  • Circuit Supply System: 3-Phase AC (400 V / 3 Loaded Conductors)
  • Nominal Line-to-Earth Voltage Uo: 230 V
  • Conductor Material: Copper (Cu)
  • Conductor Insulation Thermal Rating: XLPE / EPR (90 degC)
  • IEC 60364-5-52 Reference Installation Method: Method E / F - Perforated Cable Tray / Ladder in Air
  • Conductor Cross-Section S: 70 mm2
  • Parallel Cables per Phase: 1
  • Design Load Current Ib: 145 A
  • Protective Breaker / Fuse Nominal Current In: 160 A
  • One-Way Cable Route Length L: 85 m
  • Load Power Factor cos(phi): 0.85 cos phi
  • Ambient Air / Ground Temperature T_amb: 35 degC
  • Circuit Grouping Derating Factor Cg (Table B.52.17): 0.85 factor
  • IEC 60364-5-52 Annex G Voltage Drop Limit Category: Power / Motor / Distribution Feeder (Max 5.0% V-Drop)

3. Engineering Troubleshooting: Corrective Actions When a Reading Fails

  1. Upsize conductor cross-section S [mm2], add parallel cables per phase, or lower breaker thermal setting Ir so Ib <= In <= Iz is strictly satisfied.
  2. Upsize feeder cross-section or split load across sub-distribution boards whenever voltage drop exceeds 3% (lighting) or 5% (power).
  3. Replace steel gland plates on single-core cable entries with non-magnetic 3-5 mm aluminium/brass plates or cut anti-eddy slots between phase holes.

→ Try This Worked Example Live in Module #31 (Cable Ampacity & V-Drop)