Re-wiring Layout

@cjack, like you I was apprehensive. How could tiny little levers hold wires securely? Do they really accept the smaller gauge wires well?

I can say after using them, they were an absolute upgrade to the wire nuts I had been using prior. They are a good compliment to terminal bus bars. Any new wiring on my layout as well as any disturbed wiring gets the wago lever nuts.

It's one of those things that once you actually have hands-on experience with them you'll wonder why you ever doubted.

Yep, that 3M double sided auto tape is really really strong.  But, you got to make sure that the surface is really clean and dry first.   No grunge or dust. 

Just used it last week to replace a trim piece on the side of the truck.

You only get one chance to get it right, though, so make sure that things are line up when you press it down on the underside of the table.

Mannyrock

I believe, but am not 100% sure, that the ground or common wire means that any ground wire for anything can be attached to a ground or common bus wire. Is that true?

If so, can I attach to the common bus wire all ground wires for the inner and outer main loops that are independently powered and interconnected?

Can I also attach to the common bus wire all ground wires for all of my 9 independently powered sidings?

In addition, can I attach to the same common bus wire all ground wires for my numerous postwar accessories? Arnold

Arnold yes as long as they are going back to the same transformer that the hot is coming from. Not sure of how many transformers you have powering your layout. You have to make sure that you are using a large enough wire and that the common is being spread out back to the transformer.

Arnold,

You'll get plenty of different opinions on this but I keep my ground (or common) lines separate for each of my main lines. Thus both the hot and common wires, sometimes twisted together, go from the separate TIU output terminals (Fixed 1 and Fixed 2, for two main lines), via breakers, out to the track feed points. There are some technical reasons to do this, some related to troubleshooting and also for common (mode) noise rejection. Arguably it offers some advantages for the MTH DCS control system.

@Rich Wiemann, with common ground wiring, when you phase the transformers, the grounds are bonded connected together, therefore, any ground has a return path to any transformer.

Jumping on Arnold’s post! I thought I read some where that when you run a ground around the lay out to the various items that you should return it to the u post where you started, like a complete loop. Any thoughts on this.

thanks , Tstark

Running a hot and return twisted pair does have some advantages. Maybe not so important to an O Gauge layout, but it is a proper transmission line. Twisting reduces the self inductance of the wire and reduces the input and outgo of electromagnetic interference. Arguably yes, but.

@bmoran4 posted:

@Rich Wiemann, with common ground wiring, when you phase the transformers, the grounds are bonded together, therefore, any ground has a return path to any transformer.

I have two Z4000 transformers that are phased; one powers the 2 main lines, and the other powers the 9 sidings. Since both of these transformers are phased, including plugged in to the same power strip, I believe I can run all of the ground wires for the main lines and sidings to the same common bus wire.

The accessories are powered by a ZW, and the 022 switches are powered by a 2nd ZW. Both ZW transformers are also plugged in to the same power strip, and are probably also phased with each other and the Z4000 transformers, but there is no compelling reason to connect them to the common bus wire. The 022 switches have no ground wire, only a hot wire plugged in to the switch. Also, although the accessories contribute to the rat's nest of wires under the train tables, I'm hoping I don't need to re-wire them amy time soon.

Do you think the above is correct? Arnold

@tstark posted:

Jumping on Arnold’s post! I thought I read some where that when you run a ground around the lay out to the various items that you should return it to the u post where you started, like a complete loop. Any thoughts on this.

thanks , Tstark

According to bmoran4 and Rich Wieman, if the transformers are phased, the grounds are bonded together, so the ground wires for all the lock-ons attached to the track powered by those phased transformers can be connected to the same ground bus wire.

Arnold, sounds like you phased your ZWs to your Z4000s but neglected to keep the grounds bonded connected. As such, you have 2 distinct "common ground" circuits. This isn't wrong, but introduces isolation which may or may not be desired, especially when considering track powered activated accessories.

The O22s pick up the common ground from the outside rail of the connected track.

@bmoran4 good to know. Also I run only conventional and have no digital control so my input is based upon my own operational experience.

Progress report:

All of the hot wires for the 2 main lines are labelled and connected to the MTH Terminal Blocks powered by one Z4000.

I have also disconnected and removed all of the ground wires  for the 2 main lines except for the ground drop wires from the lock-ons. My next big project is to install the common bus wire the entire length of the layout and place terminal strips at 7 or 8 locations and connect the ground drop wires to those terminal strips (each with a bare 18 gauge copper wire threaded through the lower row of screws.

I now have substantially less wire underneath my layout. Instead of looking like a huge rat's nest/ bowl of spaghetti, it now looks like a medium sized one. LOL.

I have not yet started re-wiring the wires for the 9 sidings powered by the 2nd Z4000.

I once had a professor that would frequently say "as is obvious to the casual observer..."! There are many things about wiring that are not always obvious. You have correctly phased the two Z4000's supplying track power. The downside of using a common return is the current (amps) in the return is the sum of all the current in the four supply channels. So if two handles are supplying 4A and two are supplying 2A during operation the common return is carrying  12A, greatly increasing the voltage drop unless a much larger return conductor is used.

If there are transformers supplying loads like lighting , these do not have to be in phase. One can use two separate transformers for these kind of loads and have them 180 degrees out of phase. Then, if each transformer supplies 4A the sum of the currents in a common return is Zero. This works for loads that do not need to be in phase, not for track power.

@bmoran4 posted:

Arnold, sounds like you phased your ZWs to your Z4000s but neglected to keep the grounds bonded connected. As such, you have 2 distinct "common ground" circuits. This isn't wrong, but introduces isolation which may or may not be desired, especially when considering track powered accessories.

The O22s pick up the common ground from the outside rail of the connected track.

So, does it follow that I won't have this problem as long as I do not connect the ground accessory wires to the common bus wire for the main lines and sidings?

@AmFlyer posted:

I once had a professor that would frequently say "as is obvious to the casual observer..."! There are many things about wiring that are not always obvious. You have correctly phased the two Z4000's supplying track power. The downside of using a common return is the current (amps) in the return is the sum of all the current in the four supply channels. So if two handles are supplying 4A and two are supplying 2A during operation the common return is carrying  12A, greatly increasing the voltage drop unless a much larger return conductor is used.

Tom, I'm sure what you say is accurate and I appreciate your input, but I do not fully understand it. LOL.

When I run my trains, I rarely run more than one locomotive at a time. I will often run a train from my inner loop to my outer loop, and vice-a-versa,  and from a main line to a siding, keeping the track voltage the same for the main loops and sidings.  By limiting my train operations this way, based on what you say, I think I will be OK connecting the ground wires for the main lines and sidings to the same common bus wire.

Does that make sense?

@Arnold D. Cribari posted:

So, does it follow that I won't have this problem as long as I do not connect the ground accessory wires to the common bus wire for the main lines and sidings?

What problem do we speak of? Connecting or not connecting the grounds of phased transformers does not pose a problem either way. Generally speaking, most Lionel documentation recommendations are around one single common ground circuit. Connecting the common ground terminals on all transformers (in phase) would be the direction I would recommend and have personally taken on my layouts. It is more adventitious in my opinion do things in this single common ground manner to avoid more complex situations with track activated accessories such as crossing gates, non-derailing switches (O22s), connecting signals, operating cars and so on.

What is said above about additive current and whatnot is true, but generally this is addressed naturally because one can have multiple taps from the common ground to spread the load out and not need to run chunky wire everywhere.

@bmoran4 posted:

Arnold, sounds like you phased your ZWs to your Z4000s but neglected to keep the grounds bonded connected. As such, you have 2 distinct "common ground" circuits. This isn't wrong, but introduces isolation which may or may not be desired, especially when considering track powered accessories.

The O22s pick up the common ground from the outside rail of the connected track.

So, does it follow that if I simply connected wires between a U Post for each of my transformers (two Z4000 and two ZW), and all transformers are otherwise phased, that all ground wires can be connected to one common ground bus wire without any problems?

@Arnold D. Cribari posted:

So, does it follow that if I simply ran wires between a U Post for each of my transformers (two Z4000 and two ZW), and all transformers are otherwise phased, that all ground wires can be connected to one common ground bus wire without any problems?

Yep, they should all have a common ground, that will do it.

Arnold, If you are not loading all four of the Z4000 handles at once that minimizes the current in a common return. If you are usually running just one train then you are fine. As mentioned above in three rail it is always best to tie the grounds together for anything that is connected to the track like action accessories. That connection is usually at the transformers but can be at the track as I commented.