You might have some questions whenever you plan to power an outlet using any circuit. I think having those doubts is entirely reasonable. And I can also attest to being confused many years ago about using a 15 amp GFCI outlet on 20 amp circuits.
In general, you can practically and legally use a 15 amp GFCI outlet on a 20 amp circuit under the following conditions.
- There should be other outlets on the same circuit.
- Or you can use a duplex outlet.
Continue reading to get a clear-cut answer.
Can You Put a 15 Amp GFCI Outlet on a 20 Amp Circuit?
Yes, you can put a 15 amp GFCI outlet on a 20 amp circuit, but it is a little complicated. You should follow at least one of the following conditions.
- The 15 amp GFCI outlet cannot be the only outlet on that circuit. There should be another 15-amp or 20-amp receptacle on the circuit.
- Or you can use a duplex outlet.
Now let’s further discuss these two conditions.
Condition 1 – Two or More Outlets
If you put a single outlet on any circuit, that outlet’s power rating should not be less powerful than the branch circuit. It is clearly stated on the NEC 210. 21(B)(1).
That means in a 20 amp circuit, you cannot use a single 15 amp GFCI outlet. Instead, you can use a 20 amp outlet.
However, you can use two 15 amp GFCI outlets. Or you can use a 15 amp GFCI outlet with a 20 amp outlet. But remember, using a single 15 amp GFCI outlet on a 20 amp circuit is risky.
Condition 2 – Using Duplex Receptacles
A duplex receptacle is another way to put a 15 amp GFCI outlet in a 20 amp circuit. It ensures that you have at least two outlets on that particular circuit.
If you aren’t familiar with duplex receptacles, here’s a simple explanation.
What are Duplex Receptacles?
As the name suggests, duplex receptacles have two outlets. And you don’t have to worry about NEC 210. 21(B)(1) condition. These duplex outlets are capable of handling different power and amperage. So, putting a 15 GFCI duplex outlet on a single 20 amp circuit is completely safe.
Consequences of Using a Single 15 Amp GFCI Outlet on a 20 Amp Circuit
You now know the two ways to put a 15 amp GFCI outlet on a 20 amp circuit. But did you know what happens when you use only one 15 amp GFCI outlet?
Well, the GFCI outlet can get overloaded, and it might lead to overheating. And overheating can result in many issues, such as electrical fire or shock. Even though GFCI breakers are safe, we cannot completely rule out these risks regarding electricity.
Why are GFCI Outlets so Special?
Unlike ordinary outlets, the GFCI outlets have a safety feature that protects you from fatal or severe electric shocks. Also, GFCI outlets can detect ground faults. Hence, they are less vulnerable to electric fires. However, as I mentioned above, that doesn’t mean GFCI outlets are completely electric fireproof.
Safety Feature of GFCI Outlets
Without a doubt, GFCI outlets are the safest options for residential and commercial use. They come with a quick turn-off feature whenever a short circuit or ground fault occurs. Because of that, more and more people are leaning toward GFCI outlets.
The NEC recommends installing GFCI protections for all the following locations.
- Garages
- Bathrooms
- Outdoors
- Boathouses
- Sinks
- Kitchen Countertops
- Shower stalls and bathtubs
- Unfinished basements
- Laundry areas
- Crawl spaces
- All the single-phase outlets are rated 50 amp or less.
- All three phase outlets are rated 100 amp or less.
The Maximum Number of 15 Amp GFCI Outlets Allowed on a 120/240V Circuit
Knowing the maximum number of GFCI outlets is also good for you and your home’s safety.
With that in mind, representing the maximum number of GFCI outlets on a 120/240V circuit:
| Circuit (Volts) | 120 | 240 |
| Circuit (Amps) | 15 | 15 |
| Circuit (VA) | 1800 | 3600 |
| Outlet (VA) | 1800/180 | 3600/180 |
| Total Outlets | 10 | 20 |
Important: NEC recommends every outlet be measured at 180VA. Hence, for a 120V circuit, you can use a maximum of ten 15 amp GFCI outlets. And for 240V circuits, you can use a maximum of twenty 15 amp GFCI outlets.
Take a look at some of our related articles below.
- How to test GFCI outlet with multimeter
- How to wire a 2 pole GFCI breaker without neutral
- How to test an electrical outlet with a multimeter
Video References
This Old House
MegaSafetyFirst
Green Residential
