ZS-Solid Core Post Insulators;ZSX-Catanary Post Insulators;C-Operation Post Insulators;W-Anti-pollution Type;Numerator after frist"-"-Rated Voltage;Denominator-Catilever Failing Load;N-Torsion Failing Load;L- Pansi ndi Pamwamba Zonse zili ndi Screw Hole;Data pambuyo pa sekondi"-"-Class of Pollution Level.