Home Wiring Colors Red Black And White. According to standards in use since the mid 1900s a wire color code identifies the purpose of each wire in an electrical circuit. These colors for hot wires are not mentioned in the nec but recommended and used by electricians as general practice.
White wires are always neutral in 110 volt circuits but can be used as the second hot wire or switch leg in 240 volt applications and three way switches respectively. All nm cables contain the basic black insulation and white insulation wires plus the bare copper or green insulated ground wire. This wire may be red without an h attached to it depending on if you have a dual transformer setup.
Phase 3 phase 3 wiring should be blue.
As hot wires can be connected to each other a black wire can be connected to a red wire. Phase 1 phase 1 wiring should be black. Phase 2 phase 2 wiring should be red. Green electrical wires green wires connect to the grounding terminal in an outlet box and run to the ground bus bar in an electrical panel.
