Low voltage amperage and electrical codes

Nothing,what you had was local building code.

The ZW-L was designed to meet UL type safety standards not local

building codes.

If you want to run 350 va thru exposed metal rails, thats your problem.

If you are concerned about the installation of this type of wiring, best to call your local code enforcement office.  Similar low voltage systems, Security, Fire Alarm, Telephone are either excluded from standard wiring, or a separate permit is required for each system.  There is a pretty good chance a local electrical inspector would not know a whole lot about layout wiring. IMO

That is in the national electrical code. Company was national and worked in more than 1 state and locality.

UL approves only the transformer, not the wiring from it. UL will not approve anything they have not tested, which would be all the wiring you add after you get the transformer.  All that wiring is covered by the electrical codes.

Not concerned, was just more curious than anything. Also I know most of our layouts are residential, which is a bit different as well. I've never worked in residential. And you are probably right about the local inspector not knowing about train layout wiring, unless he has one at home. 

Don't recall the last time I saw it, but some places used to require the telephone wiring to be in conduit. The job electricians would run the conduit and the phone company would install the wiring. Most fire & security now days is plenum cable and no conduit above accessible ceilings. Fire is a bit different because of the life safety involved, fire department is usually in on that system along with inspector.

There are attempts to protect this type of installation.  Transformers have at least thermal/magnetic cut outs. As we ramp-up, (More power Tim!!!), some of what I see has some potential hazard to it.  This morning I was responding to a thread where there was a question about paralleling power sources, more power.   My experience when I first worked with parallel power, (2) Parallel PH 135's, (250 watts), (smaller than the PH180's),  was that the spark and arc on de-rail needed addressed. I added fuses and eliminated the spark and arc, felt much better at that point. IMO  some of this power equipment is approaching the point where it needs to be monitored.
(Track fuses) 7.5 amps or less. Upper middle of picture, right of vertical grey wire tray.

Accessory circuit fuses.  3 amps or less, many are 1 amp. Upper middle of picture, left of vertical grey wire tray.

I did some extensive Atlas switch wiring, installing 6924 relay boards that were rated at 8 amps.  My track circuits are fused at 7.5 amps.  Doing power routing through the boards, de-rails on a switch burned more than one relay board.  I added additional fusing to the relay board power routing circuits.
(Atlas 6924 relay board rated at 8 amps).   Fuses pictured are 3 amp.

So if you are doing damage to components, there is a concern.  Obviously not your Grandfather's toy train wiring. IMO

The ultimate control, is when I leave the room one switch turns it all off.  The receptacle bottom left of the picture controls all layout power.

Additional picture showing the switched power outlet, lower left and plug strip. Switch is by the light switch for the room. 

Mike CT,

Very nice setup you have there. Sounds like you have it all pretty well protected, and put a lot of thought into it as well.  I plan to have some good circuit protection also, if I ever get my layout plans all sorted out and get going.  As you have done, I already installed 2 switches at the basement stairs, one for my trains and workshop power, and one for the lights in that area.  Only have one 20 amp breaker for power, was contemplating adding another?

What are you powering with that Acme xfmr in the upper left corner? How many va is that beast? (You get that from Tim? )  I have some of that wire management trough, company moved one time and warehouse guy was on the way to dumpster with it, re-routed him to the back of my service van!

You helped me out with the 6924's a couple weeks ago (thanks again for that one, and to the others that helped also), think I have that down now.  Except, are you saying that derailments burnt up the 6924's and/or the relays in them? Is that what you added the 3 amp fuses to protect? I have only been fiddling with them on the bench so far, no trains yet.

I may have answered my own original question while thinking about all this? Since the layout is not part of the structure (house) and is a free standing entity so to speak, the codes may not even apply to the layout wiring?  

Breakers for lights and power are separate, I was trying to say only one 20 amp was used for power, was thinking about an additional 20 amp for power (thinking of Tim). Lights are on a separate 15 amp breaker with no outlets, which I'm getting close to full on also. Lots of lights (bad old eyes), may also need another one of those someday.

750 va would definitely power some accessories, even at Tim's place! I do see the need for lots of fuses.

The 3 amp fuse just registered when reading your reply above about the 6924's, I remember seeing it on the Atlas wiring diagrams now. I think that is something I will certainly be adding also. It is clearly needed.

Good point you make on the portable wiring, hadn't thought of that. It really would be interesting to see what an inspector said about layout wiring like you describe here. Wonder if they would be impressed, shocked, or clueless? You could probably count on them finding something wrong somewhere, just because they are inspectors.

Never let government regulations ruin an otherwise perfectly good day. My "restricted" electrician's license (primarily used for telecom work) restricts me from working on circuits "in excess of 90 Volts."  The bureaucrats found out that telephone circuits use 90 Volts AC when a phone is ringing, so they set the license limit at that voltage level. What they didn't take into consideration is the fact that telephone circuits use 48 Volt DC for talking, SUPERIMPOSED with the 90 Vac ringing, for a grand total of ~ 138 Volts.

There is no mention in the NEC of "toy electrical trains" so don't worry, is my advice.