I wanted to replace a single pole switch in a two gang box with a switch/outlet combo so the switch and outlet work independently (or the outlet is always hot). One single pole switch (switch #1) in the box seems to be on a switch loop powering an outside light as both the hot and neutral are wired to the switch. Switch #1 is connected to another single pole switch (Switch #2) that powers a separate outdoor light. There are only two incoming 12/2 lines that both have black, white and ground wires. The second incoming 12/2 has the white wire attached to switch #2 and the black wire does not terminate at all and is just curled up in the back of the box. I do not believe I can wire the switch/outlet combo (please comment) but I am now wondering if this is an unsafe wiring of these two switches. The lights these switches operate work independently now. See attached pic.
Your switch on the left has the HOT Wire coming in to it. The two blacks - one of those blacks is a jumper to the other switch.
The White wires are not neutrals otherwise when you flip the switch you would have a dead short between hot and neutral and your CB should trip!
The wiring violates code!
The box looks like a DIY'er installed it - and that would explain the wiring.
Normally - your hot run would come into the box (3-wires black, white and copper in a jacket : Romex wire) from the Circuit breaker panel or as part of a loop. You would then have 2 sets of Romex (jacketed wire - 3 wires in a jacket) going out from that box to each light.
Inside your box the whites would be tied together with a wire nut and the grounds would be tied together with a wire nut.
You would have the hots (black wires) Black from CB panel on bottom screw of switch - with the black jumper to the bottom screw of the other switch, and a black from your outside light 1 to the top screw of switch 1, and a black from your outside light 2 to the top screw of switch 2.
What this means is those outside lights are wired wrong as well - just looking at the wiring - as sharp minded Harper pointed out current is probably carried by the ground! - I would say he is right on point too - because a DIY'er went cheap with the wire runs - that is why those whites are being used as hots! Now I will bring up something else - the hot coming in to this box might be fed from another nearby circuit - near to the outside light or near to the switches there - either way probably SCREWY!
Now to add an additional outlet to that box as part of a combo - First FIX your wiring to be correct according to proper practices and CODE. Then you can put a combo switch/outlet in the place of one of those switches. You should be able to do this with 3 Romex cables - 1 From box to Light 1, 1 From box to Light 2, 1 From CB panel (or from a loop) to Box.
My answer is based on what I think is in the boxes of the two light fixtures.
We know incoming power plus neutral is entering in the box for the light controlled by left hand light, AND there is a cable from somewhere with a neutral for the right hand light. This cable may be from the left hand light or from somewhere else. This cable with the neutral surely also contains a black which is probably hot. If this is not the situation, then you will have to think about how to proceed and get expert advice. I am not sure how to list all the possibilities.
Is the coiled up black wire hot? If it is, then you are in business and you may not have to drop the light to see what's in the box for the light controlled by the right hand switch. If it is not hot, then you will have to drop the light fixture from the box to make some connections.
To wire the two lights correctly (without a receptacle) so that each light is independently controlled by one switch wire each switch with one cable. The black at each switch will be the always hot and the white will be switched hot.
Look in the box for the light controlled by the right hand switch and you should see two cables, (1) incoming power black and neutral white (This cable may come from the box for the other light or from somewhere else) and (2) one cable black and white to be used for the switch loop.
The cable with the incoming power will have an always hot black and a neutral white. The neutral white should be connected to the neutral side of the light fixture and the always hot black should be connected to the black wire in the cable going to the switch, which is then connected to one side of the switch. The white wire in the switch cable is a switched hot and is connected to the hot side of the light fixture and of course to the other terminal of the switch.
Cut off* the black on the left switch close to that switch right at the screw and this will separate the two lights. You could leave the cut black on the right switch and strip and wire nut it to the coiled black in the right cable.
EDIT *When I said to cut off the black I was assuming this was a continuous piece of wire. If this is two pieces, then just remove the jumper from the left hand switch and wire nut to the coiled black which looks a little short.