TT Scale. The Ideal Scale.

Guys,

I think you may want to rethink a couple of things regarding your proposed Module Electrical Standards, before everyone goes out and buys expensive components that probably won't get used. Remember that N-trak has been doing this for many years, has three main lines plus branch lines, and does setups at shows that may involve over 100 modules. It will be a long time before TT gets to this level, so this level of complexity is overkill. One of the biggest headaches in setting up modules is dealing with electrical issues, especially when most modules are built by people with limited electrical skills at best. You want things to go as smoothly as possible at a show, especially if the participants are coming from different parts of the country, and the modules haven't been regularly set up together and operated.

Rather than copying an old set of N-trak standards (which I assume is what you have done, since it looks like you are recommending the CJ plugs and sockets no longer used by N-trak), I would suggest keeping things as simple as possible, with only bus wires for each mainline. Will you use DC or DCC? Also, be advised that N-Trak is no longer recommending the Cinch-Jones or Beau connectors for several good reasons: they are getting hard to find, they suffer from oxidation problems on the blades that can cause intermittent contact at the low voltages used for model trains, they must be soldered together, they are expensive, costing $2-$3 or more per plug or socket (that's over $6 per connection), and Radio Shack stopped handling them a long time ago.

Several years ago, N-trak changed their standard (check N-trak's current website) to use Anderson PowerPole connectors as used on many commercial displays and workplace cubicals. They are more reliable, less than half the cost of the Cinch Jones connectors, can be used with larger wire sizes (important for DCC busses), can be ganged together to create multi-pin connectors, and can be soldered or crimped(preferred). The group is just starting out, so having complex wiring standards that use many expensive components that may not be needed for many years is just not necessary at this point. You can always add complexity later if it and only if it becomes needed.

Regards,
Bill

Actually we came up with the standards on our own - well, to be more precise CSD gave us the proposal and we agreed to it. However, you bring up very good points. What do the rest of you think?

ConducTTor wrote:Actually we came up with the standards on our own - well, to be more precise CSD gave us the proposal and we agreed to it. However, you bring up very good points. What do the rest of you think?

Sorry, I must have guessed wrong about that, I did look it over quickly. It's just that the illustrations used looked exactly like the ones in the old N-trak booklets. Still, the Anderson PowerPoles are an elegant model of simple and efficient design, and way better than the Cinch-Jones/Beau plugs. I have used both, and don't want to ever use a CJ plug again!

Bill

My thoughts are that TTnut electrical standard of using standard North American household sockets and plugs is the simplest and, potentially, most cost-effective design. While PowerPoles are nice, the availability and cost may change over time. Also, for the bus connectors, there is no real need for color coding offered by PowerPoles - we can simply write the bus identification on the outlets

The only potential draw-back of using regular polarized plugs is that there is a small risk of someone pluffing the connector cord into the 110V wall outlet. However, this can be easily prevented (as commented by one of the posters here) by using very short (24-30") connector cords with plugs on both ends, and using long extension cords with sockets on both ends.

With respect to number of buses, I must admit, adding AC bus was my request, and, ironically, I may end up not using it, and doing all my switch control in 12VDC. That said, the cost of 4 bus lines vs. 3, when using duplex receptacles is only in wire and connector cords.

I would say that 2 mains plus 12VDC bus is an absolute minimum, as, even if the 12VDC bus is not connected with other people's modules, each person will still use it for their own set of modules.

Maybe I completely missed the point, but I see no issues with the current TTnut standard whatsoever.

Wow! I must apologize for my lack of diligence in reviewing the electrical standard .pdf file. In my rather bleary-eyed state last night, I somehow missed the fact that the drawings of the plugs and sockets were labeled as being 120 volt items from the electrical department at home depot or the local hardware store, and not the Cinch-Jones connectors I mistook them to be. This was hard to see on my small screen until I zoomed in to get the picture.

Guys, this is far worse than I had imagined! Not only are your standards advocating violation of Federal Electric Codes, they are dangerous as well, and in these litigious times, could well lead to a lawsuit. There are reasons that different appliances have different style plugs on them, according to the needed voltage or amperage rating. Please, whatever you do, don't use plugs and sockets intended for high voltage AC! There is a big difference between what you might choose to do individually in your respective homes, and what you are suggesting others should do by publishing standards. Please don't open yourselves up for legal action anymore than you already have, change the standards.

There is a good possibility that if you should use these plugs and take your modules to a large trainshow, especially one that requires union supervision, or has competent fire inspectors, that you will not be allowed to power up the modules, if they even allow you to get so far as setting them up. Attached is a link to a notice on the Ntrak site about stricter regulations of use of 110v power strips and extension cords, which aren't even attached to the module. See: <http://www.ntrak.org/power_strips.htm>

Regards,
Bill

That's a very good point, railtwister! The last thing people would want is for the fire inspector to not allow the modules to run at the show. Or even worse, someone actually plugging the bus into 120VAC and burning the place down!

There seems to be a disarray in terms of standards for DC connectors ( http://en.wikipedia.org/wiki/DC_connector ). It may be worthwhile exploring PowerPole or Molex or Tamiya connector options. My issue with PowerPole is that it is produced by a single company and availability/price will be an issue. Molex seems to be the most common, and Tamiya is also worth a look. Just run eBay searches and see.

Everyone,

Here's a link to the Ntrak site page that explains the PowerPoles: <http://www.ntrak.org/wiring_connectors_rp.htm> Please check it out.

Also, keep in mind, that while Molex plugs may seem commonplace, some versions of them can be extremely hard to find. Case in point, the Molexes used by Kato for their Uni-track line of tracks in both HO & N. They look like miniature Tamiya R/C car battery plugs, but are next to impossible to buy from anywhere other than Kato as pre-wired harnesses.

I think the Ntrak crew is pretty up to date on things, they've been doing this stuff for a long time, quite successfully. Some of them really are "Rocket Scientists". They could have chosen Molex, or any other brand for that matter, but they decided to go with the PP connectors. I have used these on my group's On30 modules and I really like like them. I have used the Cinch Jones (which was the earlier Ntrak standard) on my HO club modules, and compared to the PP's I really DON'T like the CJ's for reasons listed in a previous post.

Besides being very simple, hi-amp rated, and inexpensive, the PowerPoles are uni-gender (you don't need separate male and female connectors). This does make it wise to use their color coded hoods, but they are so cheap to buy that it's not a problem to have some in all colors on hand.

Bill

railtwister wrote:There is a good possibility that if you should use these plugs and take your modules to a large trainshow, especially one that requires union supervision, or has competent fire inspectors, that you will not be allowed to power up the modules, if they even allow you to get so far as setting them up. Attached is a link to a notice on the Ntrak site about stricter regulations of use of 110v power strips and extension cords, which aren't even attached to the module. See: <http://www.ntrak.org/power_strips.htm>

Good catch! I hadn't even thought about it. Let me know which plugs you guys want to change to and I'll fix the drawing. Maybe a little disclaimer that all installations should comply with codes and regulations etc.

Good idea on the disclaimer about meeting applicable electrical codes.

Bill

So we should decide what we're going to use to update the spec. I think that the 12V SAE plug would work very well for our purpose. They have a 15A current capacity (consult manufacturers specs) and are available at any automotive parts store, cheap.