Judging by the insulation on the wires, I'm guessing that the CB is replacing a couple fuseholders that once occupied the same spot. I've seen an original 1920's installation that looked pretty similar to that.
Edited to add: I just noticed the "60 amp" part of the title. I betcha that there were originally 15 or 20 amp fuses there, and that that wire is #14 or 12.
[This message has been edited by SolarPowered (edited 07-07-2004).]
