Cannon connector arc tracking fault in electron beam melter

While melting platinum-iridium in 1973, Tom heard repeated arcing inside a vacuum chamber for three weeks. Eventually traced to arc tracking inside an Army-surplus Cannon connector. Paired with the 1962 fatality on the same equipment.

I was working on the electron beam melter where the last time someone got killed in the laboratory was Christmas Eve of 1962. They used to have sparks here, and they knew it was this one wire. He reached out — it had been raining that night, Christmas Eve, the soles of his feet were wet — he reached down to pull the wire away so it would stop sparking, and electrocuted himself. Six thousand volts. In '73 I was using the same piece of equipment. I'd be sitting there for a couple of days, and I'd hear a zap inside the vacuum system, melting platinum-iridium. Of course there's a Faraday cage around it. This went on for about three weeks while I was working on it, before the technician finally realized we had to fix this. I didn't tell my wife the story for about 32 years.