NEC Article 408 and Panelboards for Data Centers

Every piece of equipment that runs on electricity today needs to follow different legal and industry standards in order to run safely and efficiently. One of those industry standard organizations is the NEC.

What is the NEC?

The NEC (National Electrical Code) is a regionally adopted standard that provides guidelines for the safe installation of electrical wiring and its corresponding equipment. While the NEC does not provide any legally binding regulations, it is often used by states, cities, and towns, as a way to standardize the enforcement of safe electrical installation and use practices. It is part of the National Fire Codes services from the National Fire Protection Association and again works to ensure safe installation and use of electrical-based equipment.

In 2008, the NEC adopted new Articles that included the definitions of panelboards for data centers, making previous standards and definitions obsolete.

panelboards for Data Centers

According to the NEC 2005 Articles, panelboards were defined and segregated into two specific types of panelboards for data centers: light/appliance and power. This meant that lighting and appliance panelboards were limited to 42 branch circuits with over-current protection, while power panelboards have been limited to a maximum of 10 percent branch circuits. These restrictions have now been eliminated with the NEC 2008 articles. This means that 84 branch panels are now within standards of compliance.

Many professionals believe that the NEC 2008 Articles result in fewer potential failure points when using one 84 circuit panel as opposed to two 42 circuit panels. Eliminating the second panel and its breaker reduces the total number of connection points. It is important, however, to consider how heat generated from the simple use of this expanded equipment will affect other electrical equipment in the area. These areas should be well ventilated and cooled to avoid failure.

It is also important to be aware that the 2008 NEC Articles now require separate equipment for ground bus for the different panelboards for data centers. While this was always considered a “best practice,” it is now documented within the Article specifically.

Redundancy for Panelboards for Data Centers

It is important to understand the use of information and equipment within the data center to ensure redundancy in case of failure. Some panelboards for data centers should have dual power feeds to the same panel system to protect equipment through a power outage. While this can make an overall system more complex, it is always a good idea to consider this type of redundancy and balance that complexity against the type of business that uses the information housed within the data center.

Another change in the 2008 NEC Articles is the requirement of arc flash labeling on all panelboards for data centers. According to the new requirement, the equipment owner is required to label the electrical equipment for safety. What isn?t specific within the new Articles is how the label should look or what it should actually document. This is a section of the new articles that will surely be clarified as questions come forth.