Ted's reference to the Ingalls study includes proposed changes to MIL-STD-1310. Furthermore: "It is recommended that the use of grounding washers in place of cleaning to “Bright Metal”..."
Best regards, Rich -----Original Message----- From: Brian O'Connell <[email protected]> Sent: Friday, August 10, 2018 4:09 PM To: [email protected] Subject: Re: [PSES] External toothed star washer used in earth connection MIL-B-5087 is superseded by MIL-STD-464, which says "Overpainting of structure for corrosion control prior to ensuring an electrical bond has been documented as the leading cause of poor or ineffective bonds." MIL-STD-464 points to MIL-STD-1541 - for space systems ARP187 - electrical bonding for aviation MIL-HDBK-419 grounding, bonding, and shielding for land systems MIL-STD-1310 bonding for ship systems Brian From: Edward Price [mailto:[email protected]] Sent: Friday, August 10, 2018 3:02 PM To: [email protected] Subject: Re: [PSES] External toothed star washer used in earth connection I seem to recall seeing an explanation in MIL-B-5087 (likely now superseded) that a star washer was not acceptable for military grounding. The rationale was that the points of the star washer created the conductive grounding path. Since the points were fairly small, and the ground fault current was high, a fault current would be forced to flow across those tiny point-contacts. This had the danger of causing the points to melt or arc. The military preference was strongly in favor of removing the paint below a ground-point’s footprint and then using a flat washer below and above the ground lug, with a split-ring lockwasher followed by a nut. I have read recent criticism of split-ring lockwashers, with machinery people now seeming to favor something like the Nord-lock locking system. Ed Price WB6WSN Chula Vista, CA USA - ---------------------------------------------------------------- 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]>
