Simply install one GFCI and connect whatever lawful number of ordinary grounded outlets to the LOAD terminals (not the line terminals!). Those go to the panel's supply (off of it), and it will safeguard them all. There is no need for any additional GFCI outlets on that circuit. If anything goes wrong with this first outlet, it will shut off the power to the entire chain.
However, if you want more than one GFCI protection in a circuit, you have two options: use GFCI outlets or GFCH circuits. Outlets are easy to install and cost less than circuits. However, circuits can provide more reliable power since everything will be connected to each other on a single wire. Also, if you ever want to change something about your GFCI outlets, such as add more receptacles, replace a receptacle, etc., you can do so without having to replace the whole circuit breaker because outlets are part of the circuit breaker load zone. The only real disadvantage of using circuits is that you cannot simply turn ones off when not needed. You must remove the power from all the outlets on a circuit to ensure no one is using them.
In conclusion, you can daisy chain as many GFCI outlets as you want on one circuit as long as they all receive power from the same LOAD terminal.
To save money, install a single GFCI and then connect extra conventional outlets to the "LOAD" output of the single GFCI. This gives the same level of security as installing a GFCI at each place. Connecting multiple devices directly to a GFCI without any additional protection can be dangerous because if one device gets too hot or corrodes then other devices may suffer from the problem too. A GFCI can only protect those connections it is connected to, so adding more outlets increases your risk of electric shock.
GFCIs can be used in much the same way as regular outlets except that they always give off a voltage even when no appliances are plugged in. Thus they can be used as safety devices to prevent shocks from electrified objects such as wires, metal doorbells, etc.
The good news is that most utilities include GFCIs in their wiring standards. The bad news is that this only protects people who use licensed contractors to do their home repairs. If you do some work yourself then you should consider having GFCIs installed for your own safety and that of your family.
Here's how to tell if there's a GFCI nearby: Look for a small black box next to the normal outlet. This is the GFCI breaker. It may say "RESIDENBL" on it instead.
Two responses Yes, in general. GFCI outlets are equipped with LINE and LOAD terminals. You can add extra outlets to the LOAD terminals, and these will be protected from ground faults as well. The LINE terminals cannot be used this way but they can be used to connect two circuits together.
In general, if one GFCI outlet on a circuit is working, then all its outlets are working. However, if there are multiple outlets on one terminal, then only those outlets are working that are connected up correctly - i.e., they're not also connected up to another LINE or LOAD terminal on the circuit.
You should check each outlet on every circuit for functionality before connecting up any other devices to the circuit. If an outlet is not working, you should replace it before connecting anything else to the circuit.
Yes, in general. You may also install a switch, but keep in mind that highly inductive loads (such as a powerful motor) might cause GFCI tripping. It's best to use switches with magnetic closures so they don't open during normal operation of your circuit breaker panel.
The installer should ensure that the load side of the GFCI is not wired to a metal surface if the outlet is in an area where metal-to-metal contact might occur (for example, inside wiring harnesses for vehicles). If this configuration is used, the outlet should be listed as "SPDT" or "TRANSFORMER TYPE". These indicate that the load side of the GFCI is not connected to the metal case but rather it is fed through the wall into another box or compartment containing the metal case of an adjacent GFCI receptacle.
An alternative method is to connect both sides of the GFCI to metal surfaces within 6 inches of each other. This ensures that no voltage can reach either terminal by way of the metal walls between them.
The final option is to have a non-metallic path between the two sides of the GFCI. This could be a pair of solid wires without any insulation or it could be two wires with some type of plastic insulation.
There is just one GFCI outlet required per circuit (assuming it is at the beginning of the line and the rest of the outlets are loaded). They are appropriately connected in parallel; if they were wired in series, you would not obtain the right voltage at the other outlets when a load is present. It is conceivable... that by accident you might connect two or more GFCIs in series instead of in parallel. This would cause all of the connected circuits to shut off together.
However, this is unlikely if you follow standard wiring practices. In this case, the GFCIs will control what has been labeled the "safe side" of the circuit, which in most cases will be the downstream side. If something goes wrong with one GFCI and no other GFCIs are involved, the only person who might get hurt is the person who tried to use the broken GFCI because he or she was not on the safe side of it.
The basic concept behind GFCIs is simple. If there is a fault in the cable between the utility box and this particular outlet, the current will flow through the downstream device anyway. The GFCI prevents electricity from flowing down the non-faulty parts of the cable when there is a problem with the main line.