In a Chicago high rise, feeders to a fire pump are below the floor of a parking garage. Fire pump controller is from around 1959. 480V 3 phase/ 150hp.
About 250' from the meter, there is a junction box in the floor. It is about another 100' to the fire pump. There is 3" conduit, and fiber bushings, at opposite ends of the rectangle shaped box. The box is falling apart. The conduit end, at the fire pump side of the box, is collapsing and closing in on the wire. There are 3 feeders. The insulation from one of the feeders is not cut but is "bulging" from the squeeze.
If after I megger the wire and find it to be OK. Can I just repair the damaged feeder? Is it acceptable to "sleeve" the damaged conduit end with an insulator?