GFCI Requirements Checker

How It Works

A GFCI (Ground Fault Circuit Interrupter) monitors the current flowing out on the hot wire and back on the neutral. If it detects a difference as small as 4-6 milliamps (current leaking through a person to ground), it trips in 1/40th of a second. GFCIs prevent electrocution in wet or damp locations.

The Formula

Variables

• GFCI — Ground Fault Circuit Interrupter -- detects current leakage to ground
• mA — Milliamps -- 1/1000th of an ampere
• NEC 210.8 — National Electrical Code section covering GFCI requirements for dwelling units
• 2023 NEC — Latest code cycle expanded GFCI to 250V and 50A in most locations

Example

A 120V 20A circuit in a bathroom: GFCI is required per NEC 210.8(A)(1). Install either a GFCI outlet at the first receptacle position (protects all downstream outlets) or a GFCI breaker at the panel.

Tips

• Test GFCI outlets monthly by pressing the TEST button -- they can fail silently.
• A GFCI outlet at the first position in a chain protects all downstream outlets on that circuit.
• GFCI breakers protect the entire circuit and are easier to install than replacing outlets.
• The 2023 NEC significantly expanded GFCI requirements -- check which code cycle your jurisdiction has adopted.
• GFCI protection is about life safety -- never bypass or remove it, even if it trips frequently (fix the underlying issue instead).