Dont know exactly what you guys are talking about.....I only know from my experiance from working on F-16's that copper wire is used in the cockpit for safetying switches and the we used 32 and 20 thousands(spelling) depending on the location and what the tech orders require.

 

Yep, copper for "break-away" feature. In general for the Army the TI (technical inspectors) were called out to inspect any item that needed safety wire whether copper or .020 or .030 thousandths, and after all the work completed and paperwork done, anytime a component requires safety wire to be used.

Other fail-safe fasteners included cotter-pins, along with special irregularly shaped nuts, nuts with plastic inserts, etc.

It was always fun (well, sorta) to watch a new guy proudly standby his work on one of the contortionist safety-wire marathons only to be told "Looks great, but guess what it's backwards." *snip*