Electrical Equipment Task-Based Risk Assessment: Using the Hazard Rating Number Method

This paper describes how a commonly used machine risk assessment methodology was ‘slightly’ modified for use to evaluate common tasks associated with electrical equipment. The method can be used to provide a hazard rating number (HRN) for a specific electrical task performed on a specific piece of electrical equipment. The author has applied this methodology to an entire site’s electrical distribution system from the incoming utility, on site power distribution, 24kV to 480V or 2400V substations, switchgear, and motor control centers. The method considers the effectiveness of the site’s maintenance program, health and age of the equipment, active / passive controls, engineering controls, use of procedures, and arc flash energies. This paper will present specific examples for the ‘as-found’ condition and then explore how mitigation methods affect the HRN score. The results can be used for decision making on how to spend capital to improve safety and prevent electrical injuries.