14-3 wire both red and black hot w/ one breaker off.
This exemplifies one of the reasons that nowadays a multiwire branch circuit (two hots, typically with red and black wires, sharing one neutral) must have a double wide double breaker with handles tied so if one half trips, the other is flipped off too.
If a 240 volt appliance somewhere else is still connected (or plugged in) to that branch circuit and turned on and you flip off one breaker, current can flow from the other breaker through, say the red wire, through the appliance and be found at the disconnected side of the MWBC, say, the black wire. The voltage would vary depending on how many 120 volt lights and appliances are still plugged in on that side of the line but could be measured as high as 120 volts.
The disadvantages of crab apple trees. In summer, the apples are too sour to pick and eat. In winter the birds come and leave dropping all over the place.
Last edited by AllanJ; 10-16-2012 at 08:09 AM.