Any advice on finding replacement fuses for 60 year old "DF" series(ex: DF8144-1 200A 230V 3Pole 30H.P.) from Square D? Square D told me that they were Class H fuses but I can not look at the fuses themselves without killing power to at least some part of a highrise apartment complex (sorry about that in the elevator). Thanks.
You're going to have to kill the power some time or other. The HP rating of the disconnect, it's amp rating, etc. aren't going to give you the answer. Shut it off, open it up, and look.
Welcome to ECN, I would recommend, you have a Licensed Electrical Contractor look at your problem, if a fuse opened, other issues may have caused it to open, in a High Rise building, the safety of many is at stake.