2 Conductor / 3 Wire – Residential Wiring Methods

  • This type of wire/cable is comprised of 3 total wires, 2 insulated conductors (typically black and white) and 1 bare copper wire.
  • Normally used to power a single-phase, 120 volt circuit by terminating the black wire on a single pole circuit breaker and the white wire on the electrical panel’s neutral bar.
  • Can be used to power a single-phase, 220 volt circuit by terminating the black and white wires on a double pole circuit breaker.  This wiring method DOES NOT provide a neutral to the equipment being powered, such as an electric heat pump or hot water heater.
  • In both of the above wiring methods, the bare copper wire is used for grounding purposes, and is terminated on the electrical panel’s grounding bar.
  • Shop NM-B (Inside) 2 Conductor / 3 Wire.
  • Shop UF-B (Outside) 2 Conductor / 3 Wire.

3 Conductor / 4 Wire – Residential Wiring Methods

  • This type of wire/cable is comprised of 4 total wires, 2 insulated conductors (typically black, red, and white) and 1 bare copper wire.
  • Normally used to power a single-phase, 220 volt circuit by terminating the black and red wires on a double pole circuit breaker, the white wire on the electrical panel’s neutral bar, and the bare copper wire on the electrical panel’s grounding bar.
  • This wiring method DOES provide a neutral to the equipment being powered, such as an electric range and/or clothes dryer.
  • Shop NM-B (Inside) 3 Conductor / 4 Wire.
  • Shop UF-B (Outside) 3 Conductor / 4 Wire.