Here a receptacle is added to a 3 way light circuit before the first switch. It is not controlled with the switches but is instead always hot. The source hot, neutral and ground are spliced to a 2-wire cable that runs to the new outlet. The 3 way switches and light are then wired in the usual way with the common on SW2 spliced to the source hot and the light hot wired to the common on SW1.
It’s not unusual for an old house to have an old doorbell lurking about somewhere that hasn’t worked in years. Fortunately, it’s likely a simple matter to get things back in working order. As illustrated in the above diagram, the parts of an old doorbell circuit include the bell, a button mounted at the door, and a battery somewhere in between the two.
This arrangement is used for computers and sensitive A/V equipment such as a home theater, to eliminate noise interference in the audio and video output that can be caused by the grounding wires throughout a dwelling’s electrical system.
This circuit breaker wiring diagram illustrates installing a 50 amp circuit breaker for a 240 volt circuit. The 6 gauge cable for this circuit has 3 conductors and 1 ground. A 50 amp circuit like this is used for clothes dryers and new kitchen range installations.