use power wire or ground/return wire?

For what I hope are obvious reasons, I switch the power side and also add the circuit protection there as well.

@gunrunnerjohn posted:

For what I hope are obvious reasons, I switch the power side and also add the circuit protection there as well.

Well, to state the obvious, switching the ground side of the circuit leaves more of the wiring (and the device being controlled) with a voltage potential to ground, raising the likelihood of a short to ground anywhere along that path even with the switch in the "off" position. By contrast, the voltage potential stops at the switch (or circuit breaker) if you interrupt the power side instead.

Always switch the power or hot wire!

Thanks for your comments. That’s what I thought but I wanted to make sure

My outlook on this is a little different.  This is AC power so there is really no difference in the power on the two wires. There is not, or should not, be anything connected to the house neutral or ground except the primary transformer coil. Some transformers have multiple posts with different voltages using different combinations, so there is no clear common. As for circuit protection, on some transformers there are circuit combinations on the secondary side that can cause over current situations and there is no over current protection. I like to put circuit protection in every terminal coming out of a transformer.   Lionel typically used the power to the outside rail as a common.  As where to switch a load, I just look at the situation and switch it where it is easy.  Lionel minimized the use of wire. On the flood light tower the metal tower is one side of the circuit, the steel rod up the center is the other. On the 156 passenger platforms they use the metal roof supports at each end as power in and and out.  Then a 6 volt lamp in a metal socket cast into the support and a steel rod between them for the final connection. The roof and platform are plastic to make this all work.  Best not to be to rigid on your wiring practices and look at and understand what Lionel did and how it works.

The diagram below shows the instruction sheet to the PW log ramp (if that's what it's called).  The directions do NOT specify what to connect 'A' and 'C'' to.  I'm not sure why I think it's so, but I assumed 'A' was to power and, thusly, the diagram cuts into the ground wire. 

I was having an issue with a short circuit and wanted to rule out any involvement of this setup.

@David Johnston posted:

My outlook on this is a little different.  This is AC power so there is really no difference in the power on the two wires. There is not, or should not, be anything connected to the house neutral or ground except the primary transformer coil. Some transformers have multiple posts with different voltages using different combinations, so there is no clear common. As for circuit protection, on some transformers there are circuit combinations on the secondary side that can cause over current situations and there is no over current protection. I like to put circuit protection in every terminal coming out of a transformer.   Lionel typically used the power to the outside rail as a common.  As where to switch a load, I just look at the situation and switch it where it is easy.  Lionel minimized the use of wire. On the flood light tower the metal tower is one side of the circuit, the steel rod up the center is the other. On the 156 passenger platforms they use the metal roof supports at each end as power in and and out.  Then a 6 volt lamp in a metal socket cast into the support and a steel rod between them for the final connection. The roof and platform are plastic to make this all work.  Best not to be to rigid on your wiring practices and look at and understand what Lionel did and how it works.

Well, fair enough -- most low-voltage wiring does not have a true earth ground as one pole, and thus does not technically risk a short circuit to true ground from the "hot" side of the wiring. However, as you point out, Lionel and other model railroad OEMs not infrequently used exposed conductors in their products, in a somewhat random fashion. I'll amend my earlier suggestions to say one should strive to minimize parts of the potential circuit that could short across a voltage potential. Sometimes (like an insulated/isolated outside rail used to activate a crossing gate) there is no choice but to interrupt the 'ground' side, leaving the device and the remainder of the circuit with a standing potential between it and that 'ground', but IMHO as a general practice it's best to switch the 'hot' side.

Any comments on the diagram that I posted of the PW Lionel Log 'ramp' = where would you suggest the wire from 'A' goes and where for the wire from 'C'?  It may not matter, technically, but as I asked up above, what would 'best practices' suggest?

thanks - walt

@walt rapp posted:

Any comments on the diagram that I posted of the PW Lionel Log 'ramp' = where would you suggest the wire from 'A' goes and where for the wire from 'C'?  It may not matter, technically, but as I asked up above, what would 'best practices' suggest?

thanks - walt

Simple- follow a standard, even if it's one you make up but ideally follow a convention like common is common.

By that, I mean OK, so this is a metal accessory right? So it's adjacent to track and outside rail. There is a chance, even if slight, that the metal structure of the accessory could touch either a train car, or the track, or a metal track tie- that in theory is common with outer rail and thus common. The switch would go in the hot terminal lead- the one not connected to metal frame of the accessory.

So- when wiring an accessory- I would ensure the terminals or posts to connect power- that the common and frame connection of the accessory- if so equipped- is common to my electrical common for accessory power, which is common to track common.

Why all this "standards and rules"?

Well it's your nightmare when troubleshooting, and even worse- say you ask a friend or get to that stage you need help. Imagine someone else walking into the willy nilly wiring system of no standard, no convention and then trying to figure out what the heck you did to troubleshoot a problem. Does that person walk away and tell you they can't help?

@walt rapp posted:

Any comments on the diagram that I posted of the PW Lionel Log 'ramp' = where would you suggest the wire from 'A' goes and where for the wire from 'C'?  It may not matter, technically, but as I asked up above, what would 'best practices' suggest?

thanks - walt

Connect the A post of the 364 to the common of the transformer.