GFCI (ground-fault circuit-interrupter) protection is required for many receptacles (outlets) throughout the house and outdoors. This protection can be provided either by a GFCI breaker or GFCI receptacles. There are advantages and disadvantages to each approach, depending on the installation. Also keep in mind that the local electrical code—the rules you must follow to pass electrical inspections—may have specific requirements about GFCI protection.
Protecting Circuits vs. Receptacles
GFCI circuit breakers are simple: You install one in the service panel (breaker box) and it adds GFCI protection to the entire circuit, including the wiring and all devices and appliances connected to the circuit. GFCI receptacles can be wired in two different ways to offer two different levels of protection. Single-location protection offers GFCI protection only at one receptacle. Multiple-location wiring protects the first GFCI receptacle and every receptacle downstream of it (including standard receptacles) in the same circuit. However, it does not protect the circuit between itself and the service panel.
Where are the Receptacles Located?
When a GFCI breaker trips, you must go to the service panel to reset it. When a GFCI receptacle trips, you reset it at the receptacle. The National Electrical Code (NEC) requires that GFCI receptacles are installed in readily accessible locations, ensuring that if a receptacle trips it's easy to get to reset it.
Therefore, GFCI receptacles are generally not allowed behind furniture or appliances. If you will have receptacles that need GFCI protection in these locations, use a GFCI breaker. Resetting a receptacle is typically more convenient than going all the way to the service panel to reset a breaker. On the other hand, if you wire a circuit for multiple-location protection from a single GFCI receptacle, that receptacle controls everything downstream.
Anything downstream can cause that receptacle to trip, and you have to find the GFCI receptacle to reset the entire protected portion of the circuit.
How Many Receptacles Need Protection
Sometimes the decision comes down to a question of efficiency. For example, if you need GFCI protection for just one or two receptacles—say, for a bathroom or laundry room—it probably makes the most sense to simply install GFCI receptacles. Also, if you're a DIYer and are not familiar with working inside a service panel, adding a receptacle is a simpler and safer job than replacing a circuit breaker. For a different scenario, let's say you're adding a receptacle circuit for a garage workshop or a large outdoor patio space. All of the receptacles require GFCI protection, and it might be more efficient to wire the circuit with a GFCI breaker so that everything on the circuit is protected.
A Few More Factors
GFCI receptacles have much larger bodies than standard receptacles, so in some instances the physical space within the wall box may affect your choice. With standard-size boxes, there may not be enough room to add a GFCI receptacle safely, making a GFCI breaker the better choice. Cost can also be a factor in the decision.
A GFCI breaker might cost you $40 or $50, versus $4 to $6 for a standard breaker. A GFCI receptacle often costs upwards of $10, compared to $2 or $3 for a standard receptacle (don't get the cheapest ones available, in any case). Finally, there's the local electrical code. Some GFCI requirements may or may not be allowed by the local building authority, regardless of what the NEC says. Consult the building department for details.