Product Certification
UL 508A & NEC 409 Resources
Information on Revised Standard
NEC 409 and UL 508A Summary
The National Electric Code requires compliance with NEC article 409 in April 2006. Some states are currently following this code, and additional states are coming on board every month. To ensure that your industrial control panels are in compliance, Rockwell Automation provides you education and tools through our "UL 508A & NEC 409 Resources" website.The New Article 409 covers "Industrial Control Panels". Industrial Control Panels are intended for general use, in ordinary locations, at 600V or less. One critical part of the new article is that Industrial Control Panels must be evaluated & marked for their Short Circuit Current Rating (SCCR). This is established by evaluating each feeder and branch circuits' SCCR and determining the smallest kA value. This weakest link will be the panel's kA value. In order to install a panel, the kA value must be greater than that of the incoming source.
How to Comply
The SCCR must be established using an approved method, one which is UL 508A, supplement SB. SCCRs must be evaluated for feeder circuits and branch circuits within the power circuit. There are three basic steps to this:- Establish the short circuit current ratings of individual power circuit components as specified in SB4.2, including all feeder and branch circuits.
- Modify (limit) the available short circuit current within a portion of a circuit in the panel due to the presence of current limiting components as specified in SB4.3 Current limiting components provide an option for obtaining a higher overall panel kA rating with smaller rated devices.
- Determine the overall panel short circuit current rating as specified in SB4.4