UL489 breaker is required for branch circuit protection. As long as the equipment is powered by a protected branch circuit, I don't think the UL489 breaker is "required" even at the entry to the PDU. UL1077 supplementary protectors should be fine for everything downstream of a UL489 breaker.
Jim Hulbert From: Steve Brody <[email protected]> Sent: Tuesday, October 29, 2024 9:32 PM To: [email protected] Subject: [EXTERNAL] [PSES] Circuit Breakers This message is from an EXTERNAL EMAIL system. Use caution and think before opening attachments, clicking links, or responding. Some clarification and/or education required. A client has a product that has an PDU that has a UL 489 CB where the branch circuit enters the PDU. All other CBs are UL 1077 supplementary protectors downstream from there. One of the downstream circuits with a UL 1077 supplementary protector is for internal servo motors, AC and DC. My understanding was that as long as the motors are not external to the product, that a 1077 device is OK for circuit protection in this scenario. Is this correct or am I wrong? Sorry I can't provide a circuit diagram. Thanks, Steve Brody [email protected]<mailto:[email protected]> C - 603 617 9116 ________________________________ 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]<mailto:[email protected]> All emc-pstc postings are archived and searchable on the web at: https://www.mail-archive.com/[email protected]/<https://urldefense.com/v3/__https://www.mail-archive.com/[email protected]/__;!!GXa4NB5MBjHR!XS_7jBF0hixrUJGhv_dN4sSbzu_sf1N8LsJECGKjIICQkEzyAUsE96sdlqZiVjALiwwymHgL1C8VwVl7CVD1XPWD1u85SEObJl39TQI$> Website: https://ewh.ieee.org/soc/pses/ <https://urldefense.com/v3/__https://ewh.ieee.org/soc/pses/__;!!GXa4NB5MBjHR!XS_7jBF0hixrUJGhv_dN4sSbzu_sf1N8LsJECGKjIICQkEzyAUsE96sdlqZiVjALiwwymHgL1C8VwVl7CVD1XPWD1u85SEOb-K9dwvo$> Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe)<https://urldefense.com/v3/__https://ewh.ieee.org/soc/pses/list.html__;!!GXa4NB5MBjHR!XS_7jBF0hixrUJGhv_dN4sSbzu_sf1N8LsJECGKjIICQkEzyAUsE96sdlqZiVjALiwwymHgL1C8VwVl7CVD1XPWD1u85SEObcgLAT7g$> List rules: https://ewh.ieee.org/soc/pses/listrules.html<https://urldefense.com/v3/__https://ewh.ieee.org/soc/pses/listrules.html__;!!GXa4NB5MBjHR!XS_7jBF0hixrUJGhv_dN4sSbzu_sf1N8LsJECGKjIICQkEzyAUsE96sdlqZiVjALiwwymHgL1C8VwVl7CVD1XPWD1u85SEObmo3CDVY$> For help, send mail to the list administrators: Mike Sherman at: [email protected]<mailto:[email protected]> Rick Linford at: [email protected]<mailto:[email protected]> For policy questions, send mail to: Jim Bacher at: [email protected]<mailto:[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<https://urldefense.com/v3/__https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1__;!!GXa4NB5MBjHR!XS_7jBF0hixrUJGhv_dN4sSbzu_sf1N8LsJECGKjIICQkEzyAUsE96sdlqZiVjALiwwymHgL1C8VwVl7CVD1XPWD1u85SEObFF3NyP0$> This email message may contain confidential, proprietary and/or privileged information. It is intended only for the use of the intended recipient(s). If you have received it in error, please immediately advise the sender by reply email and then delete this message. No one other than the intended recipient may disclose, copy, distribute or use the information contained in this message. - ---------------------------------------------------------------- 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: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://ewh.ieee.org/soc/pses/listrules.html For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher: <[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
