Wow—that brings back memories. Found the same thing a highschool ag shop. It was a 3-foot span of ¾-inch liquidtight with it’s grey vinyl jacket ‘drooled’ off. The students had clipped the welder ground clamp on an I beam, and one kid had placed his work on an outdoor bandsaw “table.” That’s when I found out that ½- and ¾-inch UL-listed liquidtight has a helical ground conductor the size of 18AWG. The otherwise similar non-listed material had a piece of string in place of the copper(!) The circuitous ground-return/bandsaw/welding table had been used like this for several weeks previous. [The instructor wasn’t too happy.]
The one thing worse is a lazy welder who hooks his ground on the wrong end of a conveyor and strikes an arc in just the wrong place—it can destroy heaps of ball bearings in minutes.
