I'm Trouble shooting a house with a back feed from two circuits that go to old knob and tube wiring. One circuit has load coming back on the return wire from another circuit. Orig'l basement feed wiring is replaced with romex, two circuits were in seperate panels, now in one new panel, I'm a little concerned how to protect the circuit? leave it on 120/240 multi-wire ckt, count actual load and make all one, 1 pole circuit? find the combined neutral point in the new feeds (might be in walls). understand this house is loaded with furniture, and has had some remuddling. my concern is some loads are AV equip. and computers. I dont want loss of neutral to put 240 across equipment, anyone have experience using "Short Stop" tool. Owner has only been here since 2007 so has no knowledge of system.