Adds requirements for underground electrical installations. A ladder or other climbing device is used to enter and leave any manhole or subsurface vault deeper than 1.22 meters (4 feet), and nobody climbs in or out by stepping on cables or hangers. Hoisting gear for lowering tools and materials into a manhole or vault must be able to carry the load and be checked for defects before use, and employees inside must be clear of the area directly beneath the opening before anything is lowered. Whenever work is under way in a manhole or vault that holds energized electric equipment, a first-aid-trained employee must be available on the surface close to the entrance to give emergency help; that person may occasionally enter briefly to give nonemergency assistance (though an attendant required by 1926.953(h) may not enter). A lone employee may make short entries into a manhole or vault with energized cables or equipment in service for inspection, housekeeping, readings or similar work if the employer can show that person is protected from every electrical hazard. Reliable communication, by two-way radio or equivalent, is maintained among all employees on the job. Duct rods are installed in the direction presenting least hazard, with an employee stationed at the far end to ensure required minimum approach distances are kept. Where multiple cables are present, the cable to be worked is identified electrically, unless its distinctive appearance, location or some other ready means makes it obvious, and the other cables are protected from damage. Energized cables to be moved are first inspected for abnormalities (except where (h)(2) allows fault-risking work on an energized cable). A cable showing abnormalities that could lead to or signal a fault (leaks of oil or compound from a cable or joint, broken sheaths or joint sleeves, localized hot spots on cables or joints, or joints swollen past normal tolerance, unless the employer shows they cannot lead to a fault) is deenergized before anyone works in the manhole or vault; the same applies if the work itself could cause a fault. Only where service-load conditions and lack of feasible alternatives require the cable to stay energized may employees enter, protected by shields or other devices able to contain a fault. Metallic-sheath continuity is maintained during work on buried cable or cable in a manhole or vault, or the sheath is treated as energized.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.