Current direction clarification?

Ok, to give you an idea of where I am coming from, the majority of my experience is from many years as an Electrician doing installs and troubleshooting & repair of AC systems and controls from residential to commercial with very little "real" industrial work.

I have always had a love for electronics and electricity since I was young and dumb discovering electricity via sticking my fingers in a lamp to see what electricity was and felt like. I think I was about 10 years old then.

Now my question, or really confusion is the way DC is treated in relation to AC. We always fused, switched, and controlled the "line" side of a circuit. That is where the voltage "potential" originates. So when a circuit was shorted or damaged or worked on we could use "lockout tagout" procedures. That way there was no electrical potential in the circuit beyond the means of disconnect.

Why is DC completely backwards from the way we do AC?

It is my understanding in a DC circuit, the "voltage potential" is at the negative pole and travels to the positive pole. The way everything I have seen in video animations and schematics like you have above have things like the fuses on the "wrong" side compared to AC. If the fuse blows, is there still not electrical "potential" in the circuit energized and just begging to find a way to get back to the battery?

I am confused with this. Am I thinking about it wrongly? Or overthinking current flow?



randofo26 days ago

It is commonly taught that electricity flows from positive to negative. Obviously, this is wrong, but it would be more fair to say electricity flow between the two. And, if possible, electricity always finds a pathway to ground.

Given that, the fuse is put on the positive side of the circuit because if it gets blown, the majority of the circuit gets grounded, keeping the majority of the circuit at low potential. So, if you were to short circuit connections in this state, little will happen because the circuit is 'off.'

At low voltages, human safety isn't as big of a consideration because we are terrible conductors, but this also becomes a factor with higher voltage systems.