Can I Replace a 15-Amp Breaker with a 20-Amp Breaker?
This is one of the most common questions electricians get — and the answer is not simply yes or no. Whether you can safely replace a 15-amp breaker with a 20-amp breaker depends entirely on the wire gauge used in the circuit.
The Short Answer
You can replace a 15-amp breaker with a 20-amp breaker ONLY if the circuit wiring is 12 AWG or larger. If the circuit uses 14 AWG wire (the standard for 15-amp circuits), you must NOT install a 20-amp breaker — it is a fire hazard.
Why Wire Gauge Matters
The breaker protects the wire from overheating. 14 AWG wire is rated for a maximum of 15 amps. If you install a 20-amp breaker on a 14 AWG circuit, the breaker will allow up to 20 amps to flow through wire that can only safely handle 15 amps. The wire will overheat inside the walls — potentially starting a fire — before the breaker trips.
How to Check Your Wire Gauge
The wire gauge is printed on the outer jacket of the cable. Look for markings like '14-2 NM-B' (14 AWG, 2-conductor) or '12-2 NM-B' (12 AWG, 2-conductor). You can check at the panel where the wire connects to the breaker, or at any outlet box on the circuit.
If you cannot determine the wire gauge, do not upgrade the breaker — have an electrician verify it first.
When It Is Safe to Upgrade
If the circuit uses 12 AWG wire throughout (common in kitchens, bathrooms, and garage circuits), installing a 20-amp breaker is safe and code-compliant. In fact, many 12 AWG circuits were originally installed with 15-amp breakers and can be safely upgraded.
What About Outlets?
Standard 15-amp outlets (NEMA 5-15) are permitted on 20-amp circuits — the NEC allows this. However, if you are upgrading to a 20-amp circuit, the outlets should ideally be 20-amp rated (NEMA 5-20, which has a T-shaped neutral slot) for full compliance in new construction.
The Bottom Line
Check the wire gauge first. If it is 12 AWG: safe to upgrade. If it is 14 AWG: do not upgrade. If you are unsure: call a licensed electrician.
Related Circuit Breaker Resources
- What Size Circuit Breaker Do I Need?
- How to Find the Right Replacement Circuit Breaker
- Why Does My Circuit Breaker Keep Tripping?
Need a 20-amp replacement breaker? The AllBreakerSales.com catalog includes all brands and types. Request a written quote to confirm the required catalog number and current availability. Call (951) 903-9804.