I opened up my bathroom light switch and fan box to replace the switches. The light is for overhead and the fan is a standard bathroom fan.
Inside the box I found 4 sets of wires (1 black, 1 white, 1 ground per set). After measuring the voltage of each black wire, I found all 4 to be hot. When I wired up the single pole switches (1 black per side of switch with all 4 neutrals pigtailed together), not only did the light and fan not work, several outlets downstream of this particular box did not work. When tested with a 3 light outlet tester, they presented with a “hot/ ground reverse” result. When I tested the voltage of the neutral line in the same outlet, I received a small voltage reading which coincides with a “hot/ground reverse” result.
I did not take a picture of how the switches were initially wired but all 4 hot lines were used and 1 line was strung across the 2 switches (not sure which terminals). The neutrals were all pigtailed together.
I’m not quite sure where to go from here.