Click here to enlarge imageCombinations cannot be created without testing and approval by a third-party testing agency. Most panel shops are ill-equipped to determine a combination. Electrical equipment suppliers, like Schneider Electric, assist control panel builders by testing various combinations for use. The result is a simple tool to aid the designer. Schneider Electric’s tool can be accessed via the Web by searching “Schneider Electric UL 508A Frameset Commitment.”
Ultimate Liability
In summary, NEC 110.9 says that equipment installed must be able to withstand the available fault current. However, NEC 409.110 only requires panel builders to mark the panel. It does not say that they have to provide a panel sufficient for the fault current. According to NEC 90.4 the “authority having jurisdiction” (AHJ) is responsible for compliance with the code. NEC 100 says that the AHJ can be a governmental entity, or person responsible for the facility. Therefore, the facility must ensure that consulting engineers require each panel builder to adhere to NEC 110.9 when complying with NEC 409. To accomplish this, the contract documents need to address this, and the plans should have SCCR ratings for each location where an industrial control panel can connect to the facility’s power distribution system.
Conclusion
While section 409 was added to the 2005 NEC, state and municipality adoption has occurred at different rates. Generally, when equipment is installed it only has to comply with the codes at the time of installation. This means that a control panel installed in 1984 only has to comply with the 1984 code.
However, successful lawsuits have been brought against building owners for not complying with current sprinkler codes in older buildings, setting a legal precedence. Therefore, a facility might want to create a proactive plan to address older control panels. A consulting engineer or well-qualified system integrator may have guidance on how to best proceed. More information also can be found at www.squared-water.com.
Compliance with NEC 409.110(3) will better enable industrial control panels to limit the damage from a fault, allowing municipalities to recover faster at a minimized cost, and better protect the health and safety of on-site personnel. WW
About the Author:
Grant Van Hemert is an applications engineer for the Schneider Electric Water Wastewater Competency Center. Van Hemert has over 12 years of water and wastewater experience. Previously he was a design and implementation engineer where he designed and commissioned automation and instrumentation systems dealing with aeration, screening, and clarification. Van Hemert, a licensed professional engineer in the state of North Carolina, can be reached at [email protected].