Brian, The best resource I know is to do an overcurrent protection and coordination study, the same as you might do in the preliminary steps in an arc flash study. Its not dependent on the load as much as the upstream wiring and OCP devices. Unfortunately, you must start at the top, the utility transformer and work your way down using the concept of available SSC in a bolted fault. Each device provides a certain level of protection, and until it is fully cleared, a certain amount of let thru current to the load. Transformers also provide some impedance to limit peak current. There is also an allowance for wire gauge and length.
Look into IEEE 1584. Best, Doug On Fri, Oct 30, 2020, 7:54 AM Brian Kunde <[email protected]> wrote: > Greetings to all. I hope this finds you well. > > Once again the subject of SCCR has come up. I have struggled for years to > find a document or someone who can explain this to me. The bottom line is > I need to know how I would determine the SCCR for my product. In one case > in particular I am currently working on, it is a 3 phase motor-driven > industrial device. It draws less than 8 amps at 230V. Internal to the > device, we have three "CC" type fuses with a SCCR of 200KA. However, ahead > of that we have a lockout/tagout disconnect device that is only rated 10KA > SCCR. > > How exactly can I determine the SCCR of my device? > > Thank you all. > > 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 > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in > well-used formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) <http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher <[email protected]> > David Heald <[email protected]> > - ---------------------------------------------------------------- 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 Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. 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: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
