The NEC 670.6 quote triggers some questions:
I wonder why industrial machinery with a safety interlock is required to have surge protection as opposed to machinery that does not have an interlock? Is an “on-off” or “run-stop” control considered a “safety interlock”? Is the “surge” a higher-than-normal power-line voltage or is it an impulse from switching or lightning? Does “effectively protected” mean passing the dielectric (hi-pot) test? Richard Nute Bend, Oregon, USA (Several inches accumulation of snow this morning, but above freezing.) From: Doug Powell <[email protected]> Sent: Tuesday, November 1, 2022 11:28 AM To: [email protected] Subject: Re: [PSES] Surge Protection Device required by NEC >From the 2020 Edition, emphasis is mine. "670.6 Surge Protection. Industrial machinery with safety interlock control devices not effectively protected from voltage surges on the incoming supply circuit shall have surge protection installed." It does not say where this protection needs to be applied, so I assume it can be within the machine or somewhere in machine supply. Also, does the product you are inquiring about fall under the definition of Industrial Machinery, NFPA 79? -Doug Douglas E Powell Laporte, Colorado USA <mailto:[email protected]> [email protected] <https://www.linkedin.com/in/coloradocomplianceguy/> LinkedIn (UTC -06:00) Mountain Time (US-MDT) On Tue, Nov 1, 2022 at 11:55 AM Brian Kunde <[email protected] <mailto:[email protected]> > wrote: It just came to my attention that section 670.6 of the US National Electric Code 2017 requires a listed Surge Protection Device (SPD) to be on any Industrial Machine that has an Interlock, or I assume any kind of safety function. Is this true? The only information I can find on the internet is from the companies that make and sell the SPDs which can often be very one sided. Is there more to this story that I am missing? Does the Surge Protection have to be listed? Are there specifications for the SPD? Is there a Surge Immunity Test that be used to validate and verify whether an additional SPD is required or not? Thanks, The Other Brian - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> _________________________________________________ To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
