Hi Chet:
I am not one of those who test and inspect physically large equipment. The question I have is: What hazard, if any, arises when the 480 volts insulation fails? Can it short to accessible parts? If a hazard arises, then you should do a hi-pot test of that insulation. Best regards, Rich ps: You don't need a test table! From: Chester Summers <[email protected]> Sent: Friday, February 27, 2026 12:27 PM To: [email protected] Subject: [PSES] hipot considerations for large electric machinery? Hello, colleagues- I'm looking at hipot testing a physically large electric machine and trying to determine the best approach to complete the task. NFPA 79 & C22.2 No. 301 say hipot is required, IEC 60204-1 leaves it to the manufacturer's consideration. The machine supports outdoor construction work, contains several 3-phase 480V motors and is powered by on-board genset, all mounted on semi truck trailer. Process control is done through simple pushbutton switchgear panels. There are no programmed electronics or PCBs. This is by far the largest product I've considered for hipot. Isolation of the product isn't feasible (won't fit on test table :) and disassembly is strictly limited. I'm looking for practical guidance from those that routinely test and inspect physically large equipment. IR and ground bond testing are already planned. Risk assessment thus far tells me hipot may not be essential, however, the standards say. How should I address this elephant? Thanks in advance & best regards, Chet Summers - ---------------------------------------------------------------- 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://pses.ieee.org/wp-content/uploads/2024/12/EM-PSTC-List-Rules.pdf 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
