I am replacing two 25-year-old (original) GFCI outlets in my kitchen with these:
I am confused as to why they are wired differently (one has both sets of leads in to/out of same contact screws, the other has leads in at one contact screw and out at the other end)? Why? Should I change anything or wire new ones exactly the same?
It depends what else is on the circuit. For example, if everything after the 2nd outlet there is ceiling lights, then there would be no advantage to putting them on the load side. It would just cause nuisance blackouts. Now if you trip that 2nd outlet the way it is, everything else can stay on.
Only the first outlet in a series needs to have the GFCI protection, as long as you connect the wires from the breaker to the LINE side of that first outlet. Then you can connect the rest of outlets to the LOAD side, and these outlets can be regular (=cheap) ones. If the outlets are to be GFCI by code (ie close to a sink), you must put a sticker on these regular outlets saying "GFCI protected."
However, this sometimes causes issues. For example, a ground fault occurs but the user of the kitchen does not understand why the whole series went off, and why it does not get fixed by resetting the breaker. It's not always obvious. For example, the first outlet in the series can be in a place far from the others, as it happens in old houses. So many people, including me, prefer to put individual GFCI outlets, so that when a fault occurs, only that outlet goes off, and most likely the user will figure out that they can press the "reset" button on that outlet. When all of the outlets are GFCI, you wire them all to the LINE side.
In general, cables run from one outlet to the next to provide power to several outlets.
If a GFCI outlet is in the chain, it can provide GFCI protection to the next (and all subsequent) outlets by attaching to the "Load" terminals (the ones not providing power, in your case the ones covered by yellow tape). The downstream outlets would all be ordinary ones,but would be GFCI-protected. They require special stickers if so.
Or, the chain can continue from the other, "Live" terminals, the same ones feeding the GFCI outlet. Then the downstream outlets are not GFCI protected.
You have one example of each.
It saves money to use the "Load" terminals if you want to provide a lot of outlets for convenience in a room that requires GFCI outlets everywhere.
The reason for the label is that your GFCI won't work if you get it wrong.
This is the power incoming from the circuit breaker. This side must be hooked up correctly, regardless of the setup.
This is the side with the tape over the terminals. This side connects to downstream outlets that need GFCI protection. It's common in, say, a new kitchen, that you have one GFCI protecting all the outlets on a given counter. Given how pricey GFCIs are (plus how they work) it's impractical to have multiple GFCIs in this sort of setup.
The most common mistakes are
You have a multi-room circuit. I have several stories about this, but the most relevant one here is that someone decided to add a GFCI in a bathroom that was inexplicably tied into the light circuit for the other end of the house. In fact, I found several GFCIs where the previous owner wired them into the series.
If you have downstream (LOAD) outlets that are in another room, they almost certainly do NOT need GFCI protection. The way you wire a GFCI for that is you nut the wires together, with a pigtail (branch) added for your GFCI (connected to LINE only). That way the GFCI does not affect any downstream outlets.
You have more than one GFCI in the same circuit. I have two GFCIs on a circuit in my house because the circuit goes
This got confusing when there was a GFCI trip because it's likely your upstream GFCIs will trip first. Plus the bedroom outlets don't need GFCI. So each bathroom got its own GFCI on a branch. The hallway bathroom has a downstream nightlight outlet, so it lives behind the the GFCI branch. A trip on either will not affect the bedroom.
