Edinburgh Napier University

  Cost estimating techniques are approaches towards delivering reliable estimates for any projects or endeavour. However, the usage of the different estimating techniques available depends on prevailing circumstances revolving around such project while the reliability and accuracy of each of the estimating techniques quite differ from each other. This study had through literature review identified six (6) electrical cost estimating methods and through a structured questionnaire assessed the causal factors influencing the usage of the six estimating methods. Data were retrieved from 80 respondents and analysed. The results of the study indicate the most critical causal factors as incomplete details in electrical working drawings, the absence of electrical design drawings and unclear/ambiguous electrical specifications. The study also proffered probable solutions to five of the most critical causal factors. In addition, site-observed productivity constants of electrical technicians at three different residential project sites were obtained which will serve as a valuable cost tool for estimators when carrying out electrical cost estimating jobs. The findings of the research have considerable implications for the education, training and practice of estimators in the construction industry.