Developing a new distribution test system (DTS) for evaluation of customer interruptions costs (ECIC) is described in this paper. The test system is obtained from a well known standard test system (RBTS) containing different load types and sizes. Using Matlab software, accurate and approximate procedures for ECIC are implemented on DTS. Effects of outages duration, events occurrence time, customers' type, customers load profile, customers' damage functions, customer demand values, etc. (i.e. cost affecting factors) on customers interruption costs are investigated and compared in two different ways. Simulation results confirmed the effectiveness of the proposed DTS in ECIC and demonstrated that the real value of customer interruption costs can only be obtained by considering all cost affecting factors. (C) 2009 Elsevier Ltd. All rights reserved.