[HayZee518]

Since you said fuses still, I'd have to ascertain that you are referring to old knob and tube wiring of the 40's.
Although a ground fault will trip on a two wire circuit - it's really better to be on its own dedicated circuit that has an earth ground. Knob and tube circuits never had a ground installed - just two jute insulated wires.
See if you can find a way to get a cable from the bathroom to the basement or where your fuses are located. You'll need to attach something called a sidearm disconnect to the existing system. This is just a fused disconnect switch with a neutral and ground bar inside.