Interactive diagram + guide

GFCI outlet wiring diagram

LINE or LOAD? Pick your setup and press TEST on the diagram to see exactly which outlets a GFCI protects.

Tool
Interactive gfci outlet wiring diagramThree steps: pick your setup, flip the switches, wire it

Step 1 of 3

Which setup do you have?

Look in the box with the breaker off: what matters is where the power cable comes in. Pick the one that matches, or keep the one already selected.

Step 2 of 3

Press TEST on the GFCI

Tap a switch, button or GFCI on the diagram. Glowing wires are carrying power right now. On a small screen, scroll the diagram sideways.

GFCI Outlet Wiring for a Single Location (LINE Terminals Only) wiring diagramPower inOutlet box14/2 cablebare copperwhiteblackFrom breakerHOThotNEUneutralGNDgroundGFCI outlet (reset)ONLINELINE brass screwLINELINE silver screwLOADLOAD brass screwLOADLOAD silver screwGNDgreen ground screw
  • Black: hot
  • White: neutral
  • Red: hot / traveler
  • White + black tape: hot
  • Bare copper: ground
  • Wire nut
  • Glow: carrying power now
Incoming power must go on the LINE terminals. Wired to LOAD by mistake, a modern GFCI won’t reset.

Step 3 of 3

Wire it box by box

Safety first. Turn off the breaker and confirm the power is off with a non-contact voltage tester before touching any wire. Follow your local electrical code; some areas require a licensed electrician or a permit. If you find aluminum wiring, cloth-covered wiring, scorched insulation or more than one circuit in a box, stop and call an electrician.

Outlet box

Guide

LINE vs. LOAD

The LINE terminals take incoming power from the breaker panel. The LOAD terminals feed other outlets that you want the GFCI to protect. New GFCIs ship with yellow tape over LOAD: leave it on if you aren’t protecting anything downstream. If power is connected to LOAD by mistake, a modern GFCI won’t reset.

Which wires are LINE?

With two cables in the box, only one brings power. Separate the wires with the breaker off, cap them, turn the breaker back on and test each black wire with a non-contact tester. The live one goes to LINE. If you aren’t comfortable testing live circuits, this is a good job for an electrician.

Where GFCI protection is required

The NEC requires GFCI protection for 125 V receptacles in bathrooms, kitchens (countertops and more), garages, outdoors, unfinished basements, crawl spaces, laundry areas and within 6 feet of sinks, with the details depending on your code edition.

No ground wire?

A GFCI may replace an ungrounded two-prong outlet. Mark it and any protected downstream outlets “No Equipment Ground” using the stickers in the box (NEC 406.4(D)(2)).

All gfci outlet setups

What you need

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Frequently asked questions

What happens if I wire a GFCI backwards?

Newer GFCIs detect a LINE/LOAD reversal and won’t reset or deliver power. Move the incoming power wires to the LINE terminals.

Why won’t my GFCI reset?

There may be no power reaching it (check the breaker and any upstream GFCI), LINE and LOAD may be reversed, or a ground fault downstream keeps tripping it.

Do I need a GFCI on every outlet in the kitchen?

No. One GFCI wired with its LOAD terminals can protect every outlet after it on the same circuit. Label the protected outlets.

Can I use a 15 A GFCI on a 20 A circuit?

Yes, when the circuit has more than one receptacle: 15 A receptacles are allowed on 20 A multi-outlet circuits and pass 20 A through. A single receptacle on a dedicated 20 A circuit must be rated 20 A.

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