Should a white wire (ignition switched power) ever be continuous with a black ground wire when the ignition is off?
Dear John,
Yes and no.
Think of electricity as a system of canals carrying water. The different heights of the canal represent different voltages and the flow only ever goes from a high level to a low level. The different canals can be separated by lock gates and have large and small paddle wheels between them which can be motors or lights.
If the lock gate is shut, then no water is flowing from high to low and no work is done. Whichever side of the gate you are connected to will dictate what your level is.
In this case, with the ignition switch turned to off, everything on the battery side of the ignition switch will be at 12v and everything on the other side of the ignition switch will be at 0volts. If you have a motor, which is just a coil of wire, where one wire is white and one wire is black, then you would expect to see continuity all of the way from the chassis to the ignition switch along that circuit.
If there were no continuity, then no work could be done and nothing would work, even if the gate were open for current to flow.
The water analogy also extends to how the current flows, the rate of change of flow when a gate is thrown open, ripples, tsunamis, lakes (the battery is a large reservoir high up), waterfall (the alternator is generates water in pulses and dump them into the lake from a height of “14” to height of “12”), the size of the pipes or canals relative to the amount of water, the resistance to flow, etc.
The continuity in your case should only be present through one of the components where work is going to be done. A white wire which expects to be at 12v when connected to the battery should never be directly connected to a black wire which expects to be at 0v when both are connected to the battery. If there is no component (e.g. motor, relay coil, light) between them then work is still done, but that will be reflected as heat - and a lot of it.
kind regards
Marek
1 Like
Brilliant analogy Marek, well done.
Whew, I’ll say.
I think “loop” when I puzzle electrickery If not closed, the load" will not do what it is suppossed to do.
In this case, the ignition switch opens and closes loops.
Carl