Maintenance management is a relatively new academic discipline whose purpose is to reduce the adverse effects of breakdown and to maximize equipment availability at minimum cost. Staffing is concerned with filling, and keeping filled positions in the organization structure through identifying work-force requirements; this is one of the important steps and duties of maintenance management in the recent industrial environment. In this paper, a simulation-based approach is proposed for planning the maintenance workforce of an electricity distribution company in a province of Canada. Internal and external workforces are employed to perform maintenance actions and restore power after interruptions throughout the province. According to the electricity distribution network, the province is divided into 50 operating centres (OP), each having local crews to perform maintenance actions and fix power interruptions. However, determining the size of the crew in each OP and also for each month is challenging. The reason for this is that the frequency of the interruptions differs from one OP to another and from one month to another because it is affected by various factors such as system configuration, deterioration and failure of the equipment, weather conditions, etc. The company would like to know how many internal and external workers should be available during the year to cover possible interruptions across the province with minimum cost and minimum interruption duration.