Can I put GFCI outlets in every outlet in my house?
GFCI outlets can be used anywhere where an outlet has a pre-existing ground wire. This means if your ground in your outlet is connected to your home’s electrical panel and the wire is in good enough condition to conduct electricity, then adding a GFCI outlet will provide protection for that outlet and any other outlets wired to the line side of the GFCI. (more on that later)
However, unless required by NEC or you think you need the protection, GFCI outlets are not necessary, as the ground circuit is designed to provide protection in the case of an equipment malfunction.
Example of grounding in your home
A good example of this would be a wet/dry vacuum motor that has the hot wire insulation fray and the copper wire touches the motor case. The motor case is grounded through the ground prong of the plug, so the electrical path flows through the hot and the ground instead of through a person if they touch any part of the vacuum that can conduct electricity.
Grounding is classified as a “last resort protection”, meaning a person can still get injured when grounding is in use. GFCI outlets cut off the power so fast that the likelihood of injury is greatly lessened.
Example of GFCI protection
Most toasters for non-commercial use are not electrically grounded and have a two-prong power cord. If the toaster were to get wet or a wire frayed and was causing the toaster body to become electrified, there is no protection for a person if they were to touch the toaster.
GFCI outlets sense the current flow of a piece of equipment when in use, so if a person were to touch the electrically active toaster body, the GFCI outlet would sense the change in current and cut off the power to the outlet within a fraction of a second.
Money-saving tip: GFCI outlets are 10-20x the cost of standard three-prong outlets. Following the NEC’s rules for GFCI outlets will allow you to save money while having good protection when problems occur.
Can replace a two-prong outlet with a GFCI outlet?
You should not replace a two-prong outlet with a GFCI without rewiring from the main panel to the outlet box to provide a ground. It is against NEC rules to plug in a three-prong cord into any outlet not wired with a ground.
However, a GFCI will still stop the flow of electricity in the event of a fault if no ground is wired to it. NEC even allows a GFCI to be installed in place of a two-prong outlet IF labels stating “GFCI protected” and “no equipment ground” are placed near the outlet.
This is a good time to think whether the outlet you want to change matches the criteria of needing GFCI or not. Don’t go off of what someone else previously installed, because it may not be up to NEC rules.
Do I need a GFCI breaker or GFCI outlet?
I’ve been asked this question a lot, and the answer I give today is a lot different than the answer I gave two years ago. My change of heart is due to two things: arc fault circuit interrupter (AFCI) technology, and NEC changes in 2017 to incorporate AFCI into the code.