GFCI (ground-fault circuit interrupter) protection is required for many outlet receptacles throughout the house and in outdoor locations. This protection can be provided either by a GFCI circuit 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 for how to provide GFCI protection.
Protecting Entire Circuits vs. Individual 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. In cases where AFCI protection is also called for (increasingly common), there are dual function GFCI/AFCI circuit breakers that can be used.
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 portion of the circuit that lies between itself and the main service panel.
GFCI Receptacles Must Be Accessible
When a GFCI breaker trips, you must go to the service panel to reset it. When a GFCI receptacle trips, you must reset it at the receptacle. The National Electrical Code (NEC) requires that GFCI receptacles must be installed in readily accessible locations, ensuring that if a receptacle trips, there is easy access for resetting it. Therefore, GFCI receptacles are 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, but remember that if you wire a circuit for multiple-location protection from a single GFCI receptacle, that receptacle controls everything downstream. Anything wiring issue downstream can cause that receptacle to trip, and you will have to find the GFCI receptacle to reset the entire protected portion of the circuit.
Efficiency of Installation
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 at those locations. Also, if you're a DIYer and are not familiar with working on a service panel, adding a receptacle is a simpler and safer job than replacing a circuit breaker.
In other situations, GFCI circuit breakers make more practical sense. For example, let's say you're adding a receptacle circuit for a garage workshop or a large outdoor patio space. Because all of these receptacles require GFCI protection, it is probably more efficient to wire the circuit with a GFCI breaker so that everything on the circuit is protected.
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, which may have particular GFCI requirements that are different than those suggested by the NEC. Consult the local building department for details.