This practical guide shows you how to complete a signed, QR-verified Cable Insulation Resistance & Polarization Index Calculator certificate in OhmCert Module #05 and how to troubleshoot non-compliant readings on site.

1. Step-by-Step OhmCert UI Workflow

  1. Open Module #05: Navigate to Cable Insulation Resistance & Polarization Index 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 "LV 400 V Rotating Machine / Cable (Test 500 V DC, Rmin=5 MOhm)") to populate target limits automatically.
  3. Enter Your Field Measurements: Fill in the measured inputs (Insulation Resistance at 1 minute, Insulation Resistance at 10 minutes, Insulation Resistance at 30 seconds, Insulation Thermal Class (IEEE 43-2013 Table 3), Applied Test Voltage, Winding / Cable Temperature). Blank inputs stay neutral PENDING.
  4. Complete the 13-Point Checklist: Grade each item, attach photos if needed, and export the SHA-256 signed PDF certificate.

2. Worked Numerical Field Case Study

Scenario: LV 400 V Rotating Machine / Cable (Test 500 V DC, Rmin=5 MOhm) (IEEE 43 Table 1/2) — Machines rated < 1000 V tested at 500 V DC with Rmin(40C) = 5 MOhm..

  • Applied Test Voltage: 500 V
  • rmin: 5
  • Winding / Cable Temperature: 25 degC

3. Engineering Troubleshooting: Corrective Actions When a Reading Fails

  1. Clean and dry cable terminations / motor junction boxes with isopropyl alcohol and re-test using the Guard lead to separate surface tracking from bulk moisture.
  2. Bake/dry out motor or transformer windings using controlled space heaters or low-voltage DC circulation until PI >= 2.0.
  3. Perform VLF tan-delta or partial discharge localization on cables with persistent PI < 1.5 and low R_40C.

→ Try This Worked Example Live in Module #05 (Insulation Resistance & PI)