Quick answer: An AFCI breaker detects qualifying arc-fault conditions, a GFCI breaker detects ground faults, and a dual-function breaker combines both types of protection. The right breaker also has to match your panel's approved breaker types, the circuit rating, and the protection required for that circuit.
AFCI vs GFCI vs dual function at a glance
| Breaker type | Main protection | 20A Siemens example |
|---|---|---|
| AFCI (arc fault) | Detects qualifying arcing conditions associated with fire risk | QA120AFCN |
| GFCI (ground fault) | Detects current leaking from the intended path to help protect against shock | QF120AN |
| Dual function (AFCI/GFCI) | Combines both protection functions in one breaker | Q120DFN |
All three examples are 20-amp, single-pole Siemens plug-on-neutral breakers, but they perform different protection functions. Their shared amp rating does not make them substitutes for one another.
What is an arc-fault breaker (AFCI)?
An arc-fault circuit interrupter monitors for qualifying electrical arcs and trips when it detects a condition within its design. When comparing a Siemens 20 amp arc-fault breaker with other models, check whether the circuit needs AFCI protection alone or both AFCI and GFCI. An AFCI-only model does not provide the same GFCI protection as a dual-function model. See our AFCI breaker collection.
What is a ground-fault breaker (GFCI)?
A ground-fault circuit interrupter monitors for current leaving the intended circuit path and trips when it detects a qualifying ground fault. A GFCI-only breaker is different from an AFCI-only or dual-function breaker. For a 20 amp GFCI breaker, first confirm the exact panel family and whether the circuit also requires AFCI protection. Browse our GFCI breaker collection.
What does dual function mean?
A dual-function breaker combines AFCI and GFCI protection in one device. Dual function does not mean two-pole: for example, the Siemens Q120DFN shown below is a single-pole, 20A breaker. Other models have different specifications. See our dual-function breaker collection.
Compare three real 20A breaker examples
These photos link to the matching product pages in our store. They illustrate protection types within the Siemens line; always check the exact model and your panel label before ordering.
How to choose a breaker for your panel
- Read the panel label. Open only the hinged door; leave the protective cover in place. Record the manufacturer, panel model, and approved breaker types.
- Confirm the required protection. Determine whether the circuit needs AFCI, GFCI, or both. Requirements vary with the installation and applicable code; ask a qualified electrician when uncertain.
- Match the electrical rating. Check amperage, number of poles, voltage, interrupting rating, and the exact breaker catalog number. Do not increase the amp rating simply because a larger breaker fits.
- Check the neutral connection. Plug-on-neutral and pigtail-neutral designs have different connection methods. Verify the exact breaker against the panel labeling and manufacturer documentation.
Turning off the main breaker does not necessarily de-energize incoming terminals. Have a qualified electrician handle installation or work inside the panel.
For another panel-family comparison, see our Eaton BR vs CH breaker guide.
Frequently asked questions
Is an AFCI breaker the same as a GFCI breaker?
No. They detect different fault conditions. If a circuit requires both protections, look for a listed dual-function solution approved for the panel.
Does a dual-function breaker replace two breakers?
Dual function means AFCI plus GFCI protection, not two poles or two independent circuits.
Can I choose any 20 amp breaker for a 20 amp circuit?
No. The protection type, panel listing, poles, neutral connection, and other ratings also have to match.
Will a plug-on-neutral breaker work in every panel from the same brand?
No. Check the specific panel label and the manufacturer's compatibility information for the exact model.
Which breaker do I need for my room or appliance?
That depends on the circuit, panel, installation, and applicable electrical code. Share the panel model and existing breaker number with a qualified electrician before choosing a replacement.