Power / Wiring Question

[luther_stanton]

I am finishing up the bench work on a 10 x 10 around the room 3 rail O Scale layout. I am about ready to start laying the track and have some questions about wiring / power. Any thoughts / best practices would be appreciated!

I have a single outer loop with two passing tracks in opposite corners, a small yard, a few sidings, etc. I am running strictly Lionel TMCC with a pair of K-Line F7s (both powered) a Williams Berkshire (with TA Studios EOB & sound installed) an Atlas SW8 and a Lionel GP7. I will be the only operator, so chances of more than one train running will be small to non-existant, however, a few or all may be powered on with sound, etc.

My plan was to wire up the layout with Lionel PowerHouse 180 watt transformers running through TPC 300 / 400. I was going to use a single PowerHouse with a TPC 300 for the two passing loops + yard and dual PowerHouses (360W) through a TPC 400 for the main loop. Is this too much power, if there is such as a thing [:)] ?

Second question is on feeder wires. I was planning on running the output from the TPCs directly to a terminal / bus strips like those available at Radio Shack. I was going to use 12 Gauge wire for that run and then place feeder wires off the bus strip using 18 Guage wire. Do these wire sizes sound right for the amount of power being delivered? What is the rule of thumb for feeder wires – how many feet of track between feeder, such you run the same number of feeders for the hot and common?

Thanks for any ideas / help!

- Luther

[lionelsoni]

The wire should be sized according to the overcurrent protection at the supply, regardless of the amount that the train actually uses. Anything smaller might start a fire or at least make a mess with melted insulation if there is a fault, like a derailment. The usual ampacities for building wire are 30 amperes for 10 AWG, 20 amperes for 12 AWG, and 15 amperes for 14 AWG. (Divide the power out of the transformer by the voltage to get the current.) Ampacity doubles about every 4 gauge sizes; so you can see that 18 AWG is good for about 7 amperes. A very few inches of slightly undersized wire, called a "tap", is okay for the final connection to the rail; but otherwise you should not skimp on the wire size. You can get solid 14 and 12 AWG very cheap in the form of non-metallic sheathed cable at any Home Depot or Lowes.

[tsgtbob]

What he said!!!
I get my wire, stranded, not solid, as stranded is easier to work with (IMHO) from places like Auto Zone, Advance Auto, or NAPA.
BTW, good info!!!!
Here's my .02
Use the heaviest gauge wire that is practical, I use 10 ga main busses, and 16 ga feeders off of this bus. This will minimaze voltage/amperage drops for long runs of track.
Tublar track is horrendous for voltage drops. Lockons are also terrible for getting power into the rails. "T" sectional track is better, the nickle silver rail is a better conductor of electricity. If you can, and have the skills, solder the feeders to the rails, not the rail joiners. Soldering the rail joiners will also help with getting the juice to the trains. There is a table somewhere that can be used as a guideline for power requirements, maybe someone here knows where that can be found. For every locomotive, lighted car, accessory, and powered track item (switches and such) there is a power draw that can be added up to get your finial needs. Then add 10 to 15 percent on top of that.
Also, consider using circuit breakers for each feeder, and accessory, not only for safety, but to isolate potential problems.

[lionelsoni]

You can also get stranded building wire, often in a variety of colors and gauges, at the hardward stores, by the roll or by the foot.

[Anonymous]

Your PoHo and TPC link-up,including paralleling two 180s, probably provides more power capacity than you will require including supplying a couple of long, lighted passenger trains on the same track[power district].

However, I have successfully used a similar set-up[also TMCC] with paralleled PoHos for over four years [two 135s/TPC 300 @270 watts and two 180s/TPC 400 @360 watts]. Also, paralleling three 135s under a TPC 400 is easily done, but provides more capacity than I need(400 watts/22 amps) for a single power district [my TPCs are older, original I C Controls's TPC 3000/4000 units with the 3000 upgraded from 1.2 series to 1.3].

Your TPCs and PoHos both have breakers that react in about 2.2 to 15 seconds[specs on TPCs Potter-Brumfield breakers]. However, breakers protect the power supply, not the engine circuitry. You might want to consider adding QSI PowerGards or,less expensive, Scott's Odds 'n Ends units to each power district for "current spike" arrest.

I use #12 to feed 12-position terminal strips or "hubs" strategically located and #16 for the short feeders or "spokes" which I solder to the GarGraves Flextrak rail flanges on each 37" track section. The most economical wire purchases will be # 14 and #12 stranded copper in 100' rolls from Lowe's/Depot. Generally at least four colors are available: white, red, black and green, which enables coding three separate power districts and the common return or neutral wire. I have always used white for the layout's common return since it is analogous to the household neutral returns's white code.

If you have an Automotive and Industrial Fastener supplier in your town, they carry both auto "hookup" and Machine Tool & Appliance stranded copper wire in 100' rolls and about 9-10 colors. Here in Greensboro both Piedmont Fasteners and Automotive Fasteners, Inc. carry the wire at prices below retailers such as NAPA, Auto Zone,etc.

[IronHoarse]

If you are running only TMCC then you do not need a TPC 300 or 400. They are needed for conventional only. All you need is a TMCC direct lock-on. Lionel number 6-34120. I am using one 180 watt power brick and have had no trouble running two engines at the same time while operating a crane.

[Anonymous]

Like Ironhoarse notes, I run trains on my 14x32,5-track,high ceiling TMCC shelf layout with 5 directly wired 180 PoHos.

But even in Command, one advantage of TPCs,if using PoHos, is ability to lower and set your PoHo's 18v. fixed voltage at 14-16 volts for longer passenger car bulb life.

A second advantage, also in Command, as you already know with a TPC you can parallel same-sized PoHos to increase railpower capacity above 180 watts (10 amps) in a single power district. This feature is not feasible with any other O-gauge layout/ track controller or throttle operated transformer.

[luther_stanton]

Thanks for all the information and quick replies - this is all GREAT information.

One follow up thought on taps - Leonard mentioned running taps for every 37" section - is that pretty much standard (every 3 - 4 feet)? I am usinjg the Atlas 3 rail nickel track.

Thanks again - I appreciate all the help.

[3railguy]

For feeders, every 8 sections of track should be fine if your joiners are tight. I like to add a small blob of solder on the rail flanges were they meet for sound continuity. Especially when command signals are involved. I prefer solid core wire for buss wires because it stays in place, doesn't tangle, and is easier to strip back for making T joints for feeders. For feeders, I use stranded core.

[Anonymous]

Luther
I solder to both outer rails(Commons) and the center rail[Hot} on each 37" GarGraves section [and in between Ross/Curtis switch locations because these turnouts do not pass power thru] which enables me to provide power to every single inch of track without passing thru a rail joiner where problems tend to develop.
I am not familar with the new Atlas nickel track although it appears to be a first class product based on what another O-gaugers tell me. Is this sectional or flex track and do the rail connectors/joiners make a good electrical connection? The connectors are always the key---usual source of voltage drop.

[Anonymous]

As with any sectional track that is taken apart and put back together a few times the connectors will tend to loosen. This can happen simply by going through the trial and error process during intial assembly on your layout. I took no precautions to make sure rail joiners were tight on my Atlas track and have yet to experience continuity problems as a result. I figure I'll eventually solder all the joints once I'm absolutely sure this is the track plan I'm sticking with. I used some of the rail joiners as convenient places to attach power feeds. 16 guage stranded wire tucks easily underneath the top of the joiner and holds it in place while soldering....an old habit from back in my HO Atlas track days.
One of my first posts here had to do with Atlas switches. I have since found continuity problems with them. 3 of the 4 on my layout have quickly failed to carry power to the center rail on the turnoff track. It's a rather simple fix but annoying none the less.

Bruce Webster

[lionelsoni]

If you solder all the rail joints, feeders will be unnecessary in a layout of your size.