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Understanding NEC Section 517.14: Panelboard Bonding in Patient Care Areas
Understanding NEC section 517.14 on panelboard bonding is crucial for ensuring safety and compliance in electrical inspections, particularly in healthcare facilities. This section addresses the bonding requirements for panelboards in patient care areas, which are critical zones where electrical safety is paramount.According to NEC section 517.14, the equipment grounding terminal buses of both the normal and essential branch-circuit panelboards serving the same individual patient care vicinity must be interconnected. This connection should be made using an insulated, continuous copper conductor that is no smaller than 10 AWG. This requirement ensures that all panelboards serving a particular patient care area are bonded together, maintaining the same electrical potential and minimizing the risk of electrical shocks due to differences in potential.
The section further specifies that if two or more panelboards in the same patient care vicinity are served by separate transfer switches on the essential electrical system, their equipment grounding terminal buses must also be connected using an insulated, continuous copper conductor not smaller than 10 AWG. This conductor can be broken to terminate at each panelboard’s grounding terminal bus, ensuring flexibility and ease of installation.
An important exception to this rule allows for the use of busbars as a common grounding connection point. The busbars must be made of aluminum or copper, with a minimum thickness of 6 mm and a width of 50 mm (equivalent to 1/4 inch thick by 2 inches wide). These busbars must be long enough to accommodate all necessary terminations and must be securely fastened and installed in an accessible location. This exception mirrors requirements from Article 250 of the NEC, which permits the use of busbars for grounding and bonding, thereby facilitating easier inspection and ensuring robust bonding connections.
The primary goal of these bonding requirements is to ensure that all equipment in patient care areas maintains the same electrical potential. This is critical in healthcare settings where patients and medical staff interact with various electrical devices, and any difference in potential could lead to dangerous electrical shocks. By bonding the grounding terminal buses of panelboards, NEC section 517.14 helps create a safer environment in patient care vicinities.
In summary, NEC section 517.14 mandates that the grounding buses of normal and essential panelboards in patient care areas be bonded together using a minimum 10 AWG copper conductor or an accessible busbar. This ensures uniform electrical potential across all equipment, enhancing safety and compliance. Understanding and implementing these requirements is essential for any electrical inspector working in healthcare facilities to ensure patient and staff safety.