Originally Posted by Reddevil2n
I am trying to connect a 12v fan from my composting toilet in the bathroom. There are, what looks like, a ton of white 12v wires running along the vent stack. Does anyone know if these are before or after the fuse box? Also any good way to tell which, if any, of these are positive, as they are all white, indicating neutral.
On my Keystone one of the wires has a color stripe which is the positive, and as you note, without color stripe mine is negative.
While yours does not have a color stripe I have to believe there is still a visual difference between the pos & neg. For instance, on lamp cord they're both the same color but one has ridges you can feel.
I suggest you take the cover off your fuse/breaker panel. On mine you can see the fuses when you open the door, but you have to remove the door to see the wires. Look closely at all the wires going to the fuses. Those are the positive wires. Maybe you'll be able to see some indication on the wire insulation that is different from the negative wires.
These might help if you can't find a visual difference. I bought these and some banana plug to banana plug multi meter wires. If you probe the positive wire with the red lead and get a +12v on the display, then the red lead is on the positive wire. If you see a negative sign on the display (-12v), then your black lead is on the positive wire.