On the annual christmas display I set up pn my layout each year, I’d like to wire the buildings/accesories that I’ve had but haven’t used because of layout progress. I’d like to know if the final accesory on the bus is a sawmill, will the power on the bus not return to the transformer on the neutral wire because of the sawmill power being turned off? Should I change it to a different accesory?
I’d like to help; but you’ll have to describe the situation a little better. The wires carry current, not power, which is the product of the voltage between the wires and the current through them; so power does not return to the transformer (unless you have a reactive load, which I doubt). I doubt you have a neutral, which would imply a three-wire circuit at least; you probably mean the common. What is wired to what? And what exactly is the problem?
If you wire it in “series” then the power would stop when the mill is turned off. You don’t want to wire it that way. That means the wire goes from one acc. to the next, so if you open the circuit the flow stops.
The idea of a bus is to have common power to all locations. For instance, have a common ground wire to attach each acc. to then a power feed off a central power supply to each accessory. The power side can also be a single wire that each acc. lead is attached to. The on/off switch is in one wire/side only, like a light switch in your house. That’s why some people get a shock when working on a light fixture. They think that the switch is off so the power must be off. They don’t know the hot side is still hot. That’s why you have to turn off the breaker to work on a light.
Some people like the switch in the negative lead and some like it in the positive lead. I’m not sure what is correct. I believe the negative lead should have the switch.
So the end result is that each acc. is wired to both negative and positive with a switch in one side.