Newly Installed GFCI Won't Reset at Startup: Decision Tree

Why this matters

A GFCI you just installed that will not reset is almost always a wiring problem at the install, not a defective device, though dead-on-arrival units do exist. The overwhelming first cause is line and load reversed: modern GFCIs ship shipped-tripped and refuse to reset if power is fed to the LOAD terminals. After that comes a downstream ground fault, a shared or bootleg neutral, or no power reaching the line side at all. A short ordered routine - confirm power, confirm line/load orientation, then isolate downstream - resolves this in minutes and avoids returning a working device as defective.

Symptom presentation

You wire a new GFCI, apply power, and pressing RESET does nothing - the button will not latch, or it latches and immediately pops. Downstream receptacles fed through it are dead. The device may be in a kitchen, bath, garage, or exterior box, possibly feeding several other outlets.

Quick checks

• Confirm the breaker is on and the circuit is powered: meter line-side hot-to-neutral for about 120 V.
• Identify which conductor pair is the incoming feed and which goes downstream. The feed must land on LINE; downstream goes on LOAD.
• Verify the device is not a dead-tripped reverse-wire-protected unit being fed on LOAD - the most common cause.
• Unplug or disconnect all downstream loads before attempting reset.
• Observe the reset behavior: button will not latch at all (no power, or fed on LOAD), latches then immediately pops (a real leakage fault on the connected wiring or load), or latches and holds with nothing connected (device good, fault is on a downstream load).
• Read line-to-neutral and line-to-ground on the feed. Both near 120 V means a good feed with a ground present; 120 V to neutral but low to ground hints at an open or bootleg ground that can confuse downstream testing.
• On a multi-gang or multi-device box, confirm you have not crossed neutrals between two circuits sharing the box; a borrowed neutral keeps a new GFCI from holding.

Isolation tree

Confirm power, then orientation, then downstream.

1. Power present on the intended line conductors?
   • No 120 V on the feed pair: the device cannot reset because there is no source. Trace the upstream feed - a tripped upstream GFCI, an open splice, or a feed mistakenly run to the load terminals. Fix the source first.
   • Yes, 120 V on the feed pair: go to step 2.
2. Line and load oriented correctly?
   • Feed on LOAD, downstream on LINE: a reverse-wire-protected GFCI will not reset. Swap so the incoming feed is on LINE and downstream is on LOAD. This resolves the majority of these calls.
   • Orientation correct: go to step 3.
3. Resets with load side disconnected?
   • Disconnect the load conductors entirely and reset with only the line feed connected.
   • Resets and holds: the device is good; the fault is downstream. Reconnect load conductors with downstream loads unplugged and reset; if it now trips, the downstream wiring has a leak. Walk the downstream chain for a crossed or grounded neutral or a damaged cable.
   • Still will not reset with only line connected: the line feed has a fault, or the device is defective. Re-verify the line wiring; if clean and powered, replace the device.
4. Neutral integrity. A shared neutral with another circuit, or a neutral-to-ground bond downstream, leaks current outside the sensing window and prevents reset. De-energized, ohm the load neutral to ground and to other neutrals; isolate so the load neutral returns only through the GFCI. This is the dominant cause when a GFCI is added mid-run on a kitchen or bath circuit that historically shared a neutral - the device holds only after the neutrals are separated so its sensing toroid sees a balanced hot and neutral.
5. Wet-location and exterior installs. A new GFCI in an exterior or damp box that trips on reset is often reacting to moisture already present in the box or downstream cable, not a wiring error. Dry the box, confirm the in-use cover and gasket seal, and check for water sitting in a conduit low point. If it holds dry and trips only after water exposure, the leak is environmental and the box or run needs sealing or a weep point, not a new device.

Confirming diagnosis

• Miswire (feed on load): resets correctly once feed is moved to LINE.
• No power to line: no 120 V on the feed pair until the upstream source is corrected.
• Downstream leak: holds with load side disconnected, trips when the downstream wiring is reconnected.
• Shared/bootleg neutral: continuity neutral-to-ground or between circuits; resets after the neutral is isolated.
• Defective device: powered and correctly wired on LINE only, still will not reset; a replacement holds.

Remediation

• Line/load reversal: move the incoming feed to LINE, downstream to LOAD; reset and verify the on-board TEST/RESET both work.
• No line power: restore the upstream feed - reset an upstream GFCI, remake an open splice, or correct a feed routed to load terminals.
• Downstream leak: locate and repair the damaged cable, crossed neutral, or wet box; reseal exterior boxes.
• Shared/bootleg neutral: re-separate neutrals so each branch returns only through its own device.
• Defective device: replace with a listed GFCI and confirm function.

References

• NFPA 70 (NEC) Article 210 - GFCI protection requirements and locations.
• NFPA 70 (NEC) Article 250 - Grounding, bonding, and neutral separation.
• NFPA 70 (NEC) Article 406 - Receptacle installation and wet-location requirements.
• UL 943 - Standard for Ground-Fault Circuit-Interrupters, including reverse-wire protection and trip-on-shipment behavior.
• NFPA 70E - Energized testing practices and PPE.