Is there a guide to overall layout wiring?

Model Railroader Electronics and DCC
21

Here’s how I would do it…

Break it up into 3 supplies.

1 DCC specifically to supply the track (~14.0VDCC HO)

1 for accessories (12V + 5V + Ground Lines)

1 for LED lighting

Now how much lighting do you need? Well figure out how many 60 watt bulbs it would take to light your layout. Grab 3 of 4 INCADECENT bulbs above your layout, and line them up Adjust the space between them till you reach adequate brightness. You can figure out how many lights per foot you need.

Now a 60 Watt bulb puts out about 700 lumens. So now you can figure out how many lumens per foot you need. This will help you figure out if you need to double up on your LEDs (Some aren’t as bright as others…so read the specs on lumens per meter or lumens per foot)

Next you know how big your layout is, and you can calculate the number of 60 watt bulbs your layout needs based on the bulbs per foot. (Draw it on graph paper if you have to)

A LED bulb is roughly 6’x more efficient then a traditional bulb. So 10 Watts will produce the same Lumen output as a 60 Watt bulb (same brightness) But you have to go through a power supply which is 80% efficient on average.

So lets say you calculate you need about 12 regular bulbs. That’s 12*700 lumens/bulb = 8400 lumens total. This should help you figure out how much LED strip you will need to buy. (They rate them by lumen output)

12*60 Watts = 720 incandecent Watts total

720 / 6 = 120 Watts for LED equivalent.

Would I buy a 120 Watt supply? NO! That’s running it at full tilt and that will wear it out early. I would run a supply at no more than 80% of what it’s rated at. So…

120 / .8 = 150.0 Watts supply output total.

So I would find the closest power supply that is at least 150 watts output.

150 / .8 (for 80% power conversion efficiency) = 187.5 Watts pulled f

22

So, here’s photos of my “sub-station” — warts and all!

Keep in mind that I am in the process of pulling new wire and making changes/improvements so you will see loose wire and open high voltage terminals.

I don’t have time to identify each component right now but I will go back and edit this post as time permits and try to explain the purpose of each one.

This is all fed by the two 115 VAC power strips and those are wired into several “panic switches” which I have located around the layout fascia (from my old DC days!). Everything you see here is fed from one 20A. breaker off a 50A. branch circuit.

Cheers, Ed

23

Hi Don:

Very good information. Thanks very much. I was pretty much guessing at how many LED strips I would need so this will help me sort it out a lot better.

All I’m trying to do at this point is figure out how much power I will need and how to break it up.

Thanks for your offer to help with specifics.

Dave

24

Here is the power supply I use:

http://www.ebay.com/itm/171816941910?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

It is fully adjustable with current and voltage clamps. I have it set for 4.8 Amps for my 5 Amp NCE system. The power supply trips faster than the NCE unit.

Keep in mind that all lighting should be feed from a separate breaker from your homes electrical panel. Maybe even two breakers. You don’t want to be in the dark if a power supply pukes. Even wall warts can short out.

25

My overhead fixed lighting will be completely independent from anything ont he layout for a couple of reason. One is the one you gave, don’t want to be stuck in the dark if a breaker trips because something failed on the layout. The other is that the pathway through the basement is the main way in and out of the garage - I never use my front door. I think the last time I actually entered the house that was was when the realtor was showing it. So while I plan to have all layout circuits switchable by a switch at the top of the stairs (with pilot light) so i can kill anything layout related from one point, I do not want the fixed room lights also controlled by that, so I can flip on a light, run downstairs to leave the house, or come home and flip on a light so I can see to go up stairs. I was planning to run 3 total circuits for the layout, one for the layout lighting (power supplies for LED strips), one for the rest of the layout (DCC power, structure lighting power, etc) and one for the workbench area. That should be more than sufficient to keep each circuit well under maximum permitted loads. I was also planning on more outlets than the minimum required to reduce or eliminate the need for extension cords while building the thing.

–Randy

26

One other thing. When I run a 5 engine consist, all powered, pulling 60 cars up a 2.6% grade on a curve, the current readout stays at ~1.8 Amps. This includes everything on the layout rails too. Basically this means the engines are loafing. I would like to try pulling the 60 cars up that grade with one or two engines to check the current draw, but the wheels slip. In theory it should be 1.8 amps too as that is the amount of torque it takes to move the load. ( Amps = torque )

Bottom line, you might not need as much track power as you think.

Think of it this way. If you have 20 engines sitting on your track, all with 1 Amp decoders, on the surface it would seem that you need a 20 Amp DCC system. But you won’t be running all 20 engines at the same time ( at least I wouldn’t ) and it’s almost impossible to max out a decoder, let alone 20. A 5 Amp system would probably work and a 10 Amp system surely would. And you could divide the system into blocks and have a seperate booster and power supply for each.

I have already melted a couple of Kadee trucks with my 5 Amp system. A short with a 10 Amp system could be catastrophic. The DCC systems I have used automatically reset in about a second. I guess you could use fuses.

27

Yes, you do not want to ever feed a 10 amp booster directly to the rails without some lower current circuit protection in between. ANd even 5 amps is iffy. It takes far less power to run any ‘recent’ HO loco than you might think, and if you break the layout up into logical power districts, each with its own circuit breaker, the total draw per section may well be far less than you think - if you’ve done the dividing logically, there will only be a few locos at a time in any given section. Not only does this prevent a derailment in one section from shutting down the entire layout and ruining everyone’s fun, it prevents things like melted wires, decoders, and plastic bits.

–Randy

28

Well that is kind of scary. Even 5 amps is iffy? Aren’t most HO scale boosters 5 amps?

Rich

29

Yes, but 5 amps into 12 volts is 60 watts. Ever try to touch a 60 watt light bulb that was turned on? ANd considerign typical HO DCC voltage is actually 15V - that’s 75 watts.

When my oldest was about 3 he wrecked by very nice Casio engineering calculator by putting ii in the lamp on the nightstand, which had a mere 40 watt bulb in it. By the time I noticed it in there, the plastic back had melted through. Now let 75 watts run through the plastic trucks of your loco… OK, at full power it would trip the breaker, but only a slight loss in the wires, or if the loco wheels are firmly on the track, in the case of a derailment, it may only flow 4.5 amps, which won;t trip the breaker. 4.5 amps at 15 volts is still 67.5 watts of heat generated.

Nothing in HO scale needs 4 or 5 amps to run, so limiting any given area of the layout to a lesser value is only prudent.

–Randy

30

I guess the problem I am having with that is the fact that a lot of modelers use a 5 amp DCC system to run a small layout with a single power district and no circuit breakers other than the booster. Nothing melts.

Rich

31

Randy:

In all the stuff I have read about setting up power districts I have yet to see any specific information as to what size layout should be divided into blocks. There are references to ‘large layouts’ and ‘small layouts’ but I have not seen a method of actually determining the point at which a layout should be divided up.

My layout will be 10’ x 23’ with a little over 500 feet of track. About 50% will be in staging and helices. I will power all accessories from separate power supplies. I will have a max. of three to four locomotives running at a time (one switcher and a consist) with a few others idling (if I can stand the noise). How many power districts do I need?

Thanks

Dave

32

One reason for setting up power districts is to balance power consumption by “evenly” distributing power across the layout.

But, another important reason for establishing power districts is to keep motive power moving across the layout when a short occurring somewhere on the layout would bring the entire layout to a halt. Multiple power districts can isolate a short within the specific power district in which the short occurs.

So, “evenly” distributing power across the layout may not necessarily mean dividing the layout into 2, 3, 4 power districts of equal length. More importantly, power districts are established to isolate areas of activity from one another. On my layout, for example, I have separate power districts for the mainline, the passenger station and coach yard, the freight yard, the diesel servicing facility, and the steam engine servicing facility.

Rich

33

It all depends on your operating pattern. For example, you siad you will have a helix - the helix ABSOLUTELY should be a seperate power district, simply because if someone derails and shorts elsewhere ont he layout, if there isn’t a seperate power district, the train in the helix will also come to a very sudden stop - and that’s just asking for most of the train to leave the rails. Hidden staging is another good candidate since you can’t easily see what happened in there - though it’s also not a bad idea to have kill toggles for each staging track so that people don;t move the wrong train by mistake - if someone wants to pull loco 1234 and its train from track 3, if they line up track 3 and it turns out 1234 is actually on track 2 - derailment and mess as it runs the switch. With kill switches, you line track 3, turn power on to track 3, and if nothing moves when you dial up 1234 and try to pull it out, you know it’s probably not on track 3.

Size of the layout does have some bearing on it, mainly because the larger the layout, the more trains you can have running at the same time, assuming enough people are around to run them all. So if you have multime trains all running on the main, with signals or with TT&TO, or whatever operating method you choose, if you break the main into seperate power districts, if someone goes on the ground between a-town and b-town, it doesn’t completely gum up the whole works, the rest can continue to move up until the operating rules limits. Same with a yard. By keeping the yard seperated, a derailment int he yard won;t kill mainline trains, and vice versa.

How many districts and where they are located really depends mostly on your operating scheme. Once you get past the point of a single 5 amp booster running things, you’d add more boosters, but still subdivide those to more power districts. If you built a layount in an aircraft hanger but only ever ran trains by yourself, the only reason you’d have for power d

34

I have an NCE Power Pro 5 Amp system and have melted a couple of sets of Kadee metal wheelset. The booster and/or the power supply trips, but automatically resets in less than a second. ( Kadee now makes a ‘plastic’ side framed set of trucks. these prevent the short circut that the metal ones cause )

As I am upgrading the wiring of my layout, I am looking into breakers that must be maually reset or fuses. All of the breakers/fuses will be in the area of 2 Amp or less. The other concern is the capacitors discharging back into the track even though the power has been removed. I’m am looking for some guide lines in installing MOVs ( Surge protectors. ) accross the rails.

35

Randy and Rich:

Thank you! I now have a much better understanding of the logic behind power districts. You guys are being very helpful. I appreciate your time.

I don’t anticipate ever having more than 3 operators. The walk in space simply won’t be big enough to accommodate another person without people having to climb over each other.

Based on your information I should have at least 5 districts - one for each helix, one for the staging area, one for the yard and one for the layout main line and secondary lines. There could be a 6th for the engine service facility but that is probably overkill.

The answer to my next questions will be obvious to some, but I need clarification. I am planning on using an NCE system with an SB5 as the smart booster. I know that each district will have its own booster but does that mean that each booster will be 5 amps? If so, how do I limit the amperage going into each district so I’m not melting things? NCE seems to have discontinued the lower amperage boosters.

EDIT:

I went back and re-read the NCE information on circuit breakers and I learned that I can use a CP6 to provide separate power to 6 districts with just the Powercab and an SB5 smart booster.

I also researched the PSX circuit breakers and they seem like a much more intelligent system.

Dave

36

To limit the current to any districts, protect it with a lower amperage breaker or fuse.

37

The PSX breakers have an option to set them to manual reset, so the power won’t come back on until you close the contacts with a pushbutton or similar.

–Randy

38

In case you missed my edit to my last post, I did some more research on circuit protection and I learned that NCE has a CP6 automotive light bulb protection system but it seems rather primitive. I also looked up the PSX breakers and they seem like a much better choice.

I answered my own question about how many boosters I need - one.

Seems so simple when the light finally comes on!

Dave

39

Dave, the PSX circuit breaker is an ideal choice. I use the PSX units on my layout.

If you have any reversing sections on your layout, use PSX-AR units to control those sections. The Digitrax AR-1 does not interact well with the PSX units.

And, yes, start out with one 5 amp booster. You can always add one later if that proves necessary.

Rich

40

Thanks Rich.

I’m realizing just how much I don’t know about DCC, or at least I didn’t know. Thanks to you guys that is slowly changing.

Dave