Except at points where necessarily left exposed, as at spot welder contacts, current-carrying parts of furnaces, welders, and control equipment shall be suitably guarded with enclosures or barrier guards.
34 Pa. Code § 39.263
This section cited in 34 Pa. Code § 39.197 (relating to grounding); 34 Pa. Code § 39.272 (relating to insulation); and 34 Pa. Code § 39.281 (relating to insulation).