I'm parting out a 3 kV power supply built 40 years ago. It was stored, unpowered in a dry basement for 35 years. Had no doubt the fat 450V electrolytics were heading for recycling, but didn't expect the condition of the high voltage wire. It was a major brand, bought from Allied Electronics by the spool. My gut told me it would be cracked, stiff and maybe brittle. Wrong! It flexes fine, the #18 stranded conductor looks good, and not a sign of cracking. The outside diameter is 0.230" +/-. Is this normal for rubber insulation of that era?