A common complaint by manufacturers of industrial control panels is that there is often a lack of clarity regarding the available SCCR, and, therefore the SCCR requirements of the industrial control panel. It is not uncommon for the SCCR value to be unspecified, leaving industrial control panel manufactures in a bit of a quandary regarding the actual SCCR requirements of the industrial control panel. If the panel is built for a high (ie. 65K) SCCR, then the cost of the panel goes up. If the panel is built for a low (ie. 5KA) SCCR, then the panel may not be suitable for use in the required installation.
The 2017 edition of NFPA 70, the National Electrical code, addresses this issue by requiring end users to provide documentation regarding the available short circuit at the location of the installed panel. Per the National Electrical Code article 409.22 (B) “If an industrial control panel is required to be marked with a short-circuit rating in accordance with (article) 409.110(4), the available short-circuit at the industrial control panel and the date the short-circuit current calculation was performed shall be documented and made available to those authorized to inspect the installation.” This places the burden of specifying actual available short-circuit current squarely on the shoulders of the end user.Have an Inquiry for Siemens about this article? Click Here >>