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Interactive home wiring diagrams
Most wiring diagrams are flat pictures. These are live circuits: pick your setup, flip the switches, and watch which wires carry power. Every diagram is checked by a circuit simulator for shorts, polarity and grounding, then broken down into box-by-box steps.
Interactive wiring diagrams
- Light switch wiring diagram3 setups: power at the switch, power at the light (14/3 switch loop), power at the light (old 2-wire loop)
- 3-way switch wiring diagram3 setups: power at the first switch, power at the light, light between the switches
- 4-way switch wiring diagram2 setups: power at the first switch, power at the light
- Dimmer switch wiring diagram3 setups: single-pole dimmer, 3-way dimmer + 3-way switch, smart dimmer (needs neutral)
- GFCI outlet wiring diagram3 setups: single gfci (line only), protect outlets downstream (line + load), middle of run, protect only this outlet
- Electrical outlet wiring diagram3 setups: end of run (one cable), middle of run (pigtails), half-switched outlet (split)
- Ceiling fan wiring diagram3 setups: one wall switch (fan + light together), two switches (fan and light separate), no wall switch (pull chains or remote)
- Doorbell wiring diagram2 setups: one chime, front button, front and rear buttons
Wiring checkers
- Video doorbell transformer checkerRing and Nest voltage and VA requirements
- Do I have a neutral wire?Check your switch box before buying a smart switch
House wire colors
| Color | Job | Where you’ll see it |
|---|---|---|
| Black | Hot | Incoming power, switched hot to a light, a 3-way traveler |
| Red | Hot | Second switched hot (fan light, split outlet) or a 3-way traveler |
| White | Neutral | Returns current to the panel. Spliced in the box, never switched |
| White + black tape | Hot | Re-marked white in a switch loop, feeding power to a switch |
| Bare / green | Ground | Every box, device and fixture. Never carries current normally |
| Blue | Hot | Ceiling fan light kit lead; hot in conduit |
Tools for any wiring job
- Non-contact voltage testerThe one tool you should never skip: confirms the power is off.Check price
- Lever wire connectorsEasier, more reliable pigtails and splices.Check price
- Wire stripperClean strips on 12 and 14 AWG with a strip gauge.Check price
- Outlet testerFinds reversed polarity, open grounds and GFCI faults.Check price
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Frequently asked questions
What do the wire colors mean in house wiring?
Black and red are hot, white is neutral, and bare copper or green is ground. A white wire wrapped in black tape has been re-marked as a hot, which is common in switch loops.
What size wire do I need?
Match the breaker: 14 AWG copper on 15 A circuits and 12 AWG on 20 A circuits. When replacing a device, match the wire already in the box.
Are these diagrams code compliant?
They follow common US practice and the National Electrical Code, and every circuit is checked by a simulator for shorts, polarity, grounding and switching. Local codes vary, so check with your building department.
Can I do my own electrical work?
Many US homeowners may replace switches and outlets in their own home, but rules and permit requirements vary by city and state. When in doubt, hire a licensed electrician.
Thermostat wiring
Replacing a thermostat? Our thermostat wiring tool maps your old wire letters to Nest, ecobee, Honeywell and Amazon smart thermostats.