In U.S. homes, the hot wire is usually black; red, blue, or yellow can also be hot, while white or gray is neutral and green or bare is ground.
Quick Safety Check
Kill power at the breaker, lock it out if you can, then confirm with a non-contact tester before you touch a conductor. Keep one hand away from metal while testing, wear eye protection and insulated gloves, and replace damaged cords, boxes, or devices instead of trying to patch them. If a task moves beyond simple replacement, hire a licensed electrician.
Hot Wire Color In A House In The USA — Practical Rules
American homes follow conventions shaped by the National Electrical Code. The Code reserves white or gray for the grounded conductor and green or bare for the equipment grounding conductor. That leaves the ungrounded, or “hot,” conductor to be any color that is not white, gray, or green. Tradition fills the gap: black is the everyday hot in cable, red is a common second hot, and blue or yellow often show up as hots in conduit or as switch legs. If a white must serve as a hot in a cable, it needs bold re-identification at each accessible end so nobody treats it like a neutral.
For the letter of the rules, see NEC 200.6 on neutral identification and OSHA 1910.304 on wiring design and protection. The Code sets clear limits on what neutral and grounding colors must be. It also allows re-identification of a white used as an ungrounded conductor when it is part of a cable assembly; the marking must encircle the insulation at each visible termination. OSHA’s rule underscores the need to mark grounded and equipment-grounding conductors so workers can tell them apart from the other conductors.
U.S. Residential Wire Colors At A Glance
| Conductor Role | Typical Colors | Key Notes |
|---|---|---|
| Ungrounded (Hot) | Black; Red; Blue/Yellow in conduit | Feeds, switch legs, travelers; any color except white, gray, green |
| Grounded (Neutral) | White; Gray | Only for return path; re-identify to hot if code conditions are met |
| Equipment Grounding | Green; Green/Yellow; Bare | Bonding only; never used as a current-carrying hot |
Why Black Means Hot Most Of The Time
Most branch circuits in houses are built with NM-B cable. A two-conductor cable with ground (14/2 or 12/2) ships with a black hot, a white neutral, and a bare equipment grounding conductor. That pattern is simple, easy to remember, and it drives the “black is hot” habit across outlets, lights, and small appliances. A three-conductor cable with ground (14/3 or 12/3) adds a red conductor; that red is hot as well and often serves a second pole on a split receptacle, a 240-volt load, or a traveler between three-way switches. That is why black and red keep showing up in boxes even when devices have been replaced many times.
On 240-volt loads that don’t need a neutral, installers sometimes use two-conductor cable and re-identify the white as a hot. When that happens, the white must be marked at each accessible end with tape, dye, or sleeve in a color other than white, gray, or green. You’ll find this on water heaters, baseboard heaters, and older ranges or dryers where a neutral wasn’t required for the heating elements. The marking removes doubt later, so anyone opening the box understands that the white is not a neutral and should treat it as a live conductor.
Recognizing Hot Wires By Device Clues
Color helps, but devices give away the hot feed even when colors are faded. Standard receptacles use a brass-colored screw for the hot and a silver screw for the neutral; the small blade slot is the hot side and the larger slot is neutral. Light fixtures often ship with a smooth black lead for the hot and a ribbed white lead for the neutral. Switches place the common terminal on a darker screw than the travelers. If your box contains multiple cables, cap the neutrals together and track the hot by the terminal colors and by meter readings. A pigtail from feed often lands on the common screw of a switch; the travelers go on the two brass screws of a three-way. On a standard receptacle, the tab on the hot side links the two brass screws unless it has been snapped for a split circuit.
When you replace a device, match function before you match colors. Follow the terminal markings, not just the jacket color, because old splices and sun-bleached insulation can mislead you. A brass screw wants a hot. A silver screw wants a neutral. A green screw bonds the yoke to the equipment grounding conductor. That simple map holds across modern receptacles, switches, and many fixtures.
Special Cases You’ll See In U.S. Homes
240-Volt Appliances
Large appliances like ranges, dryers, mini-splits, and some window heat pumps use two ungrounded conductors that are each hot. Colors vary by cable or conduit, but black and red are common in cable, while conduit runs might pull any non-white, non-gray, non-green color. If a neutral is present, it will be white or gray; the equipment grounding conductor will be green or bare. Never assume a white in a 240-volt cable is neutral without checking for re-identification.
Switch Legs And Travelers
Modern code wants a neutral in most switch boxes, so you’ll often see 14/3 or 12/3. The red typically carries a switched hot or serves as a traveler between two three-way switches. In conduit, blue and yellow are popular for switch legs or travelers because they stand out next to the typical black feed. Function matters more than the exact hue: if it is not white, gray, or green, treat it as a potential hot until a tester proves otherwise.
Multi-Wire Branch Circuits
Some kitchens and workshops use a multi-wire branch circuit that shares a neutral between two hot legs on a handle-tied two-pole breaker. Colors are usually black and red for the hots with a white neutral and a bare or green equipment ground. Handle ties or a two-pole breaker are critical so both hots trip together; without that tie, you could kill one leg and still have live voltage in a shared box.
Old Cable And Remodels
Older homes may contain cloth-covered or discolored conductors. Labels and past repairs can mislead you, and painters often coat conductors near fixtures. The safest habit is to verify with a meter every time. If you open a box and find a white wire landed on a device’s brass screw and marked with black tape, that’s a re-identified hot. If you find a green on a brass screw, stop and call a pro—somebody miswired a safety conductor.
Common Home Wiring Scenarios
| Scenario | Hot Color(s) | Notes |
|---|---|---|
| Standard 15A/20A Receptacle Circuit | Black | White neutral, bare or green equipment ground |
| Split-Receptacle Kitchen Circuit | Black and Red | Shared white neutral, handle-tied or two-pole breaker |
| 240-Volt Heater (No Neutral) | Black and Re-identified White | White taped any color except white, gray, or green |
| Three-Way Switch Pair In Conduit | Black feed; Blue/Yellow travelers | White neutral present in box in many modern installs |
| Ceiling Fan With Light Kit | Black motor hot; Blue light hot | White neutral common to both; green/bare to metal parts |
Step-By-Step: Verify Which Conductor Is Hot
1) De-energize the circuit. Open the correct breaker and label it. If you’re unsure which one feeds the box, turn off the main and work by daylight.
2) Remove the device or cover. Keep track of screw locations so you return conductors to the same terminals after testing.
3) Prove your tester on a known live outlet. Then test the suspect conductors. A non-contact tester should light or beep near a hot even with the neutral disconnected. A two-lead meter will read about 120 volts between hot and neutral or between hot and ground, and near zero between neutral and ground.
4) Restore power only when everything is capped. Cap off any free conductors with wirenuts before energizing so accidental contact doesn’t arc.
5) Re-assemble neatly. Land the hot on the brass screw, neutral on silver, and the equipment grounding conductor on green. Tuck pigtails so the device seats flat and the yoke doesn’t pinch insulation.
Code Tips That Prevent Common Mistakes
Leave green alone for grounding. Use white or gray only for neutrals unless a white is re-identified with tape or sleeve to serve as a hot. Mark re-identified whites at every accessible end, not just one. When you share a neutral between two hots, tie the breakers so they trip together. When you extend a circuit, keep the same or larger conductor size, and always place cables under clamps or bushings so sharp edges don’t nick insulation.
If you’re pulling individual conductors in conduit, a simple color plan keeps boxes readable later: black for line, red for switched hot or second leg, blue or yellow for travelers, white or gray for neutral, and green for equipment grounding. Label the conductors with tape in the box as you land them, especially where a white has been re-identified. Clear labeling helps the next person stay safe.
Smart Wiring Habits
Neat work and a meter beat guesswork. Treat any non-white, non-gray, non-green conductor as a likely hot until your tester proves otherwise. When you must repurpose a white as a hot, mark it boldly at each visible end. When you see black on brass and white on silver, you’re looking at a standard, safe device connection. And when something doesn’t look right—painted insulation, mismatched colors, or a green on a brass screw—stop and bring in a licensed electrician.