Very Old Receptacle with GFCI

[bowbridge]

I was replacing an old (about 1959) two prong receptacle with a GFCI. It was the first one (of four more downstream) from the breaker box. The old one only had back stab holes (no screw terminals at all). I cut the wires (one black, one white) that were going in to the two top back holes on the old receptacle, turned the breaker on and took a voltage reading across the wires, got 120 volts. Then shut the breaker off and connected the wires two top terminals on the GFCI, took a voltage reading and got 14 volts, a red light on the GFCI, and no ability to reset GFCI. After about an hour trying different things, I saw that the white wire that I had hooked up to the top GFCI was the one that was going to the next downstream receptacle, and was not the white coming from the breaker box. Looking at it closer, I saw that on the old receptacal, the white coming from the breaker box was back stabbed into the bottom hole, the black coming from the breaker box was in the top hole, the white going to the next outlet was in a top hole, and the black going to the next outlet was in the bottom hole. After getting the line wires into the top terminals on the GFCI, everything worked.

My question is why were not the line white/black wires on the old receptacle not put into both top holes, but instead the black was in a top hole and the white in a bottom hole?

Thanks for any help.

Edit: Also, why did the voltage drop when I first connected the GFCI?

 

[KenC]

Wire placement was just bad worksmanship by the original backstabber. Top and bottom holes are connected by the bridge on the side of the recept, so it really makes no difference in the circuit. The voltage reading was likely because something was plugged in on one of the downstream recpts. That will create a partial circuit with and open neutral.

 

[bowbridge]

Thanks. Yes, I did have something plugged in downstream of the first receptacle.

 

[Bert_]

On a regular receptacle it doesn't matter. Sure it might be a little neater to have line in both on top but it's not worth wasting any time on for a regular receptacle

 

[sparky 1971]

I can all but guarantee I don't match up the sides with regular receptacles. I do the ground and neutral first, landing the neutral on the screw closest to me, which will be the top, then I roll the device over and land the hot on the side closest to me again, which will wind up being the bottom when installed with the ground pin down. It's different with the pressure plate back wired type devices because the screws are loosened from the factory on top and tight on the bottom so I put both on top but it doesn't matter which side the wires are on.