[VAL] 12v wiring

["Stan Truitt" <stan.truitt@xxxxxxxxxxxxxxxx>]

hi all
12vdc current continues to baffle me at times. my understanding is that my
trailer (1966 safari) is a negative ground 12v with the white dc wiring being
negative and black being positive. there may also be other colors of positive
wiring (blue and orange) in the trailer but that the white is always negative.
this weekend, i wired up a 12v auto radio and blew the radio fuse. upon
looking closely, i discovered that i had wired the ground wire of the radio to
the positive side of the 12v. i reversed the wires, replaced and fuse and it
worked just fine. the only reason i bring this up is that i was running
speaker wire behind the rear gaucho and water pump area. it is a fairly new
atwood pump installed by a shop for the PO. i noticed that the red wire (+)
from the pump was wired to the white wire (-) of the trailer and the black
wire (-) of the pump wired to the black wire (+) of the trailer. further the
red wire from the pump also had an inline fuse, something i always thought
should be on the positive side. now, is this not in reverse of how it should
be? does it make any difference in this circumstance? i have turned the pump
on for just a second and it powered up. i cannot (do not wish to) test it
further as the water system has been winterized.
confused in colorado
harry
66 safari