Data-driven probabilistic approach to assess electrical plug loads in healthcare facilities

Abstract

This paper examines the historical context and ongoing challenges associated with electrical load sizing in healthcare facilities, focusing on oversizing electrical distribution systems mandated by the National Electrical Code (NEC). While these codes have been designed to ensure safety and reliability, they often result in larger than necessary systems, particularly in healthcare settings where energy intensity is notably high. This study presents new evidence demonstrating that aggressive demand factors for receptacles—specifically, general 180 VA and dedicated 120-volt circuits—can be adjusted to reflect actual load conditions better. We utilized a probabilistic methodology to analyze more than six million electrical load readings collected on 1196 circuits in 14 hospitals in the United States. A total of 196 hospitals were chosen randomly across the United States, and due to the conceived data privacy, measurements were only carried out in facilities that agreed to participate. We present a probability model to analyze and recommend safe design requirements based on actual plug loads in the hospital. The findings suggest a convergence of demand factors as the number of circuits increases, showcasing up to 30% savings in copper and system sizing.