I think that’s the quote from Mr. Mom–Michael Keaton was talking electrical. In the United States, most smaller electrical requirements are satisfied by 120 volt circuits and larger demand appliances like clothes dryers or stoves use 240 volt power.
Typically, residential service from the street has 3 wires (conductors). Two of the wires (ungrounded conductors) carry 120 volts each, the third is the neutral (or grounded) conductor that the current returns on to the source–a transform. When you put them together you get 240 volts.
The house below had an old old electrical system
The service cable only has two conductors entering the house, so only 120 volt electric power is possible in the house: no electric dryer, central AC, baseboard heat, electric stove, are possible.
The capacity of a residential electrical service is usually 100-200 amps, this house was a 30 amp service, that is to say, the service conductors were 10 gauge wire with a 30 amp main fuse. But as you can see, there were two meter sockets (kind of new ones) and two separate electrical services in the house all from the 30 amp two wire service in the first picture.
Of course, the wiring in the house was all knob and tube wiring–seen above meter sockets. Knob and tube is the original method of wiring installed in residential houses. By now most of it is antiquated and ready to be replaced: the wire insulation gets brittle, people tap into the wires in inappropriate ways. Basically the older an electrical system is, the more chances there are for someone to make a crazy modifications.
The above picture shows someone’s misguided attempt to add a grounding electrode system: a copper wire loosely wrapped around a water pipe. The type of grounding attempted here is earth grounding, which is for electrical surges (like lightening) to go to ground, but I doubt this installation would have any effect.