Okay it wasn’t a strong shock, but non the less it was odd. I was feeling a water damaged plaster ceiling, trying to figure out why the ceiling was corroding and rusted. Upon entering the attic I saw some knob and tube coming out of blown in cellulose insulation. The ceiling was damaged from poor flashing around a chimney and therefore water was dripping from the chimney flashing onto the insulation and therefore onto the ceiling below the insulation. Would I be correct to assume that the knob and tube is likely in contact with either the “wet” insulation/ plaster ceiling, therefore energizing the ceiling? What would cause the plaster to rust like this? This house is probably about 100 years old.