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        # Maximizing Volume Resistivity in PVC Cable Insulation

        

**Topic:** Cables

        

Your cables look perfect, but they're failing the electrical insulation tests. The leakage current is too high, and your batch is being rejected by the QC department.

        
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## Problem

Volume resistivity in PVC cables is highly sensitive to the purity of the raw materials. Impurities in CPW or the presence of moisture-absorbing fillers can drastically reduce the insulation resistance. Even a small amount of residual catalyst in the resin can create conductive paths.

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## Likely cause

This issue often stems from inconsistent compounding temperatures, inferior raw material purity, or unbalanced stabilizer ratios within the formulation matrix.

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## Corrective direction

Using high-purity NBT DOTP or specialized electrical grade DOP is the first step. More importantly, using NBT Diamond Grade CPW ensures that no acidic by-products are formed during extrusion, which would otherwise lower resistivity. We also recommend using treated Calcium Carbonate to minimize moisture absorption.

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          ## Frequently Asked Questions

          
### How does CPW affect electrical properties?

High-quality CPW acts as a flame retardant without significantly impacting resistivity, provided it is free from ionic impurities.

### Can I use recycled resin for electrical cables?

It is highly risky due to unknown impurities. We always recommend virgin NBT PVC Resin for insulation layers.

        
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By NBT Technical Desk · Updated 2026-06-07

        

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