How does Article 230 approach service load calculations for multifamily dwellings?

Article 230 of the National Electrical Code provides guidelines for service load calculations in multifamily dwellings, emphasizing a comprehensive approach that takes into account both individual and common loads.

Individual loads refer to the specific electrical demands from each unit or living space within the multifamily setting. These loads can vary significantly depending on the type of appliances, HVAC systems, and other electrical devices used by the residents. By considering individual loads, the calculation ensures that the service is adequately sized to meet the needs of all occupants without risking a shortage during peak usage times.

Common loads, on the other hand, pertain to shared facilities and amenities such as hallways, laundry rooms, exterior lighting, and any other collective electrical systems that serve the entire building. These loads are essential to account for, as they contribute to the overall demand on the electrical service.

By approaching service load calculations this way—incorporating both individual and common loads—Article 230 ensures that the electrical system is designed not only to handle the specific demand of each unit but also the shared facilities, ultimately contributing to the reliability and safety of the entire multifamily dwelling’s electrical system. This methodology helps prevent overloading and ensures that there is adequate capacity for all electrical needs across the building.