Proficiency Testing as a Method of laboratories External Quality Control- Case Study of Wire and Cable Laboratories

Proficiency testing is one of the external quality control techniques that can determine quality control program efficiency in each laboratory. The purpose of this paper was studying laboratories’ skill in measurement of conductor electrical resistance and determining factors to improve the performance of laboratories. In this paper, according to the results of implementation of the standard harmonized project (Taha) in Iran in 1392, number of standard Co. laboratories and also the importance of safety in electricity industry, Solid conductor cable is selected as proficiency test item. In this article, some significant factors affecting in the test results like complying with isothermal conditions, type and calibration status of instruments and implementing laboratory quality management system based on international standard ISO/IEC17025 were studied. This process was done with 19 participants based on sequential participation scheme. According to the statistical analysis, laboratories were ranked based on Z-score and the difference, D. 63.15% of participants obtained acceptable Z-score and D in measurement of electrical resistance parameter in the conductor. Statistical analysis shows that 60% of participants who achieved “A” quality level, have appropriate and calibrated instruments and isothermal condition and implement ISO / IEC 17025 on their management system.