I am trying to set up a outdoor patio. I realized that I have this outdoor outlet that is not set up. I did some research online and learned that to set it up:
test electricity for which one is line and load
connect it to a gfci outlet.
However, I noticed that there are 2 white and 3 black with one green wire. Isn't it usually 3 whites and 3 black with green as ground?
I am super new to electricity and DIY things in general. So thank you guys for your help.
That's because your wiring is in conduit, which is actually the deluxe way to do things.
I disagree with the advice you are getting regarding "hook the supply wires to LINE and the other wires to LOAD". You should not use LOAD at all, ever, unless you are doing a very specific thing, you know exactly what you are doing, and you comply with Code in doing it. That "thing" is extending GFCI protection to other outlets. You must label those outlets "GFCI Protected", which obviously requires that you know which ones they are lol.
Protecting random downlines-you-know-not-where seems like a "can't hurt, might help" sort of thing... but actually, it can go badly wrong several ways, and you don't have the experience to resolve those problems. It is likely to turn into a fiasco... Just avoid LOAD altogether as a general rule.
Those wires don't appear to be color-coded. My guess is you are looking at
2 whites = neutral (supply and onward) 2 blacks = always-hot (supply and onward) Solo black = switched-hot
If there's a switch somewhere that appears to do nothing, that may switch this wire. (provision for Christmas lights?) Perhaps they wanted to give you the option of a "split receptacle" (one socket powered one not). That won't happen with a GFCI obviously, but you could choose whether to attach the GFCI to the unswitched or the switched wires.
So you'll be putting 1 or 2 wires on each LINE terminal... read the GFCI instructions for how to do that, and torque the screws HARD (preferably to spec with a torque screwdriver).
As described in my original comment and in the other answers, you likely have a switched hot in the mix and will need to figure that out in order to know which wires to connect.
But the other part is what to connect them to. Obviously, a GFCI receptacle. The catch is that GFCI doesn't do well with getting wet, because it is full of sophisticated electronics - at least compared to a standard receptacle. You definitely should use a weather resistant receptacle and it should also have an in-use cover.
A weather resistant receptacle costs more but is better able to handle the hot, cold, wind & rain. Even weather resistant, a GFCI receptacle on the outside of the house will not usually last as long as one on the inside, but it helps.
A proper in-use cover keeps most of the rain out while letting you leave a cord connected. That is different from some other covers which really only protect the receptacle when it is not in use.
There is an alternative: Place the GFCI inside the house. But without knowing what other receptacles or lights or other devices are on the circuit, that runs into the issue raised by Harper regarding LINE vs. LOAD.
It is common to have a red and black in this case with the red being a switched hot. Having 2 blacks would suggest you have conduit , and one could be a switched hot.
usually