Electrical load questions

Model Railroader General Discussion (Model Railroader)
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Hello all

I am finally about to realize a life long desire to build a space dedicated just to building a HO freelance RR with approximately 100’+/- feet of main line based on the N&W. The space will be 24’x24’. The beneral plan will be have an “M” shape, single level, with a possible second level added in the future.

Here is the question. I have to bring power from the house to this building. In the start of the design process I am trying to consider all of the elcrtical needs so I can bring the proper amount of power to this building. I know I will need basics like heat, lighting. I need to figure out the power needs for the controls, lighting of the buildings, street lights, controls switches and anything I may not have consdered that I will need power for.

From your expierence what size curcuit will layout this size require just for the train ? Any thing I should consdier that I may have not thought of ? What lessons along the way have you learned that you would do differently ? Any tips that I should consder ?

Thanks in advance for your feed back.

YGW

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I run my entire garage with a 220 30 amp subpanel. Never run out of power but your main power eaters will be lighting and depending on how you heat it, heat could also be a consideration along with air conditioning depending on where you live.

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So this is an outbuilding. I would do nothing less that 110/220 100 Amp Service. Is it more than you need? Darn right it is. How much more will it cost that 110v 30A service: Almost nothing. Put the Capicity in, you will never be sorry for that. If you sell the property it will be an asset.

Train room of LION is 110v / 15A way too small for the same size room you have. But I use a wood shop in a different building for my power tools.

ROAR

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YGW:

When calculating the power required make sure that all of your calculations are done at the same voltage. 120 volts is best since that is what your main panel for the building will be working at.

For example, if you want to use a 10 amp command station keep in mind that it is measured @ 12 volts, not 120 volts. At 120 volts the command station is only drawing 1 amp. Things can become a bit confusing if you don’t convert the amperage power consumption to 120 volts for everything. I posted a thread asking the same question a while ago and it went on for two or three pages before it became clear that we were not using 120 volts as a common denominator. The bottom line was that 20 amps @ 120 volts would be plenty for the layout itself. That was based on a 5 amp (@ 12 volts) command station with a maximum of 5 or 6 sound locomotives operating at any single time. In case you are wondering, I don’t plan on trying to run 6 locomotives individually all at once. There will be an ABA consist cirulating on the loop with one or two switchers running in the yard.

Rrebell suggested that lighting will be a major consumer of power. I’m assuming he was referring to lighting for the layout room, not for stuff on the layout. I strongly recommend that you investigate the latest LED room lighting. There are now 4’ LED light tubes that fit directly into fluorescent light fixtures (with the ballast removed) that consume very little power and produce tons of light. As a bonus, they are dimmable and they won’t produce the same levels of UV light as the fluorescents will. UV light will eventually fade your scenery.

I invested a fair amount of money in LED strip lighting (the stuff that comes in 5 meter rolls) and the necessary power supplies just before the LED tubes became available. I wish I had waited! The tubes are far easier and simpler to install. If you go the LED tube route, I would wait as long as you can before buying the tubes. They are quite new to the market so i

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And in my case, because I run a dehumidifier pretty much year-round, the cost of running one of those both in cash and in energy-allotment has to be considered.

Dave, just above, mentions reducing power consumption with new tech or devices when possible. Luckily, I was visiting Home Depot locally for that purpose and the nice lady mentioned new LED panels, flat ones that hug the ceiling. WOW!!! They are incredible! I now have four of them in my new train room. They aren’t cheap, but they’ll pay for themselves in about five years with my rate of consumption. So, I heartily agree with Dave…get some LED ceiling panels and don’t look back.

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I run a dehumidifier in the basement to keep it at about 50% during the summer months, along with the A/C etc. (heat pump) and the electric bills are not far off from the winter month bills where the de-humifiier is not running but I’m still heating. It doesn’t seem to impact the elect bills terribly much from what I can see. Granted, it’s a town home basement and not a nice big ranch basement which I would like to have but would cost more to dehumidify.

I have been changing out my lighting in the train room. I started with four 4’ T8 conventional flourescent fixtures that have 2-32W bulbs in them (64W total per fixture) with 4’ LED fixtures that are 40W each. They are a little more expensive but are coming down in price - I got them for about $35 each - they have more lumens and longer life too. If you go all LED, that should save on electricity.

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Hello all,

As a former electrician I would suggest hiring an electrical contractor for a consultation.

What you are describing is more than just an extension cord run from the main building.

Have a list of equipment that you will be needing to power and add another 20% for headroom (future expansion). Most manufactrures can supply you with the needed specs.

This will give you some idea of your power needs and how much it will increase your electrical bill too.

From there you can determin if your single-phase service will suffice or if you’ll need to upgrade to a three-phase service.

Also, a consultation will allow you to get an idea of what the costs will be of powering this building safely.

Hope this helps.

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I am also having an outbuilding put up. It will be a shop and garage. Heavy power use will be welder (50 amp outlet) and compressor (30 amp outlet). It will get a 200 amp panel. If it were practical to run power over from my house (it isn’t), I would install a 100 amp subpanel instead.

My prevous two homes had similar setups and also had two 200 amp panels, one for the house proper and one for the shop. One home was fed from a single meter providing 400 amp service. This particular house needed two full 200 amp panels because my wife also had her own shop with heavy electrical requirements. Both homes had single phase power.

My local utility provides free EE consultaion on new construction, so I took them up on it. He agreed on the new 200 amp service. He also stated that a 100 amp would be adequate but not cost effective, because of the expense of running power from the house to the shop versus a new service (free). There were no suprises.

None of these installations were anywhere near needing 3 phase service.

Private homes with 3 phase power are extremely rare in my experience. In the military I had the “pleasure” of living on 3 phase power for a number of years. At one location we regularly burned out AC units designed for 120/240 that we were forced to run on 208. While I’m sure there are AC units designed for 3 phase power, I am equally sure they cost a whole lot more that the run of the mill 120/240 volt variety.

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YGW - Congrats on getting to the point of constructing your railroad. Always nice to know another railroad is going up.

Take a walk over to your power panel in the house you have now. Open the cover door and take a look at all the breakers you have in your house.

Add up all the amp ratings on the breakers. Comes to a few hundred amps huh! In Virginia it is code that you have a “Main shutoff” breaker on your main box. The number that you added all the breakers up to should be less than this main breaker rating.

Hopefully, your added number is way less than your main breaker. If not, your in trouble! If so, this difference is the amount of amps that you have extra that you may install a sub panel from (or other circuits in your house even).

IE: 500amp main breaker - 360 amps in house now = 140 amps you can use without having to change your main breaker or box.

I cant see why you would need anything more than 120vac out to your new room. And supposing you have atleast 150amps in the clear - this should be perfect!

Remember, an engineer designs things to be twice what they will ever be used for. If you stick a 200amp service out to your room, you will be fine… with amps to spare. Is it too early to be thinking of expanding the layout room? lol

IE: With a 150amp service you could break that up at the sub panel into 15-10amp circuits, or 7-20amp circuits with 10amps unused as a safety margin. Ofcourse, you said ac/heat was going in, so there is 50amps gone right there. leaving 100amps for everything else.

I can see a 200 amp service well covering all your needs to include any future modifications down the road.

The above describes pulling power from your existing main box AFTER the main breaker. If you want to be savvy, you can tap off your line AFTER the meter BEFORE your main house box. This would leave you open to put just about any kind of service out to your new room.

Your only concern the

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Thanks for all of teh feed back so far from Douglas, Central Gulf, JJd, Rio Grande, Selector, lion, RR bell and Douglas

I should have mentioned earlier in my post I have met with my electrican already. I have a 200 amp service and I will need to install a sub panel to feed the new building. I pretty much have a handle on the building service itself that will cover outlets, exterior lights, HVAC. The info I do not know is the power needs for the layout itself. How many power districts will it take for roughly 100’ of main line, how many power packs at what amp ? What will all of the misc lighting for the street and town lights take ? The building ( HO scale on the layout ) lights take ? Signal power needs ? Switch power needs ?

I need to ball park the power requirements for the layout itself for the electrician so that he can build the service accordingly. Douglas is on the right track ( no pun inteneded) with his comments.

I do appreciate the other comments too though there were a few ideas I had not considered and are well worth taking into consideration.

Thanks and I look forward to your additional input.

YGW

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(I wrote this as YGW was writing the previous post. I’ll leave it as-is.)

Total ballpark (as in, ya gotta start somewhere):

For a building of this size, I’d allow 30 amps (at 240) for electric heat. If it is needed (maybe there’s also a gas line?).

I would allow for the general load 3 watts per square foot. That’s 7.2 amps (at 240).

I would add something for the not insignicant tool load that will occasionally come up. Being as a real saw can draw about 13 amps (at 120), I’d add 13 amps (at 240).

For the layout itself, I am just not coming up with much load. I’ll allow 5 amps ( at 240).

So, adding up comes to 25.2 amps without electric heat and 55.2 amps with.

I see there was mention of a second floor someday. Loads up there should be figured in now.

So, tentatively, I’d run a minimum of 30 amps (240) or 60 amps (240). Bigger is ALWAYS better. Except, sometimes, when it’s the BILL that’s bigger.

It sounds like the out-building would be fed from the house. You’ve got to also re-calculate the combined system to see if you need a larger service. This is something you don’t want to be blindsided on, 'cause it’s almost always expensive.

The National Electrical Code is the official source on sizing all of this stuff. In my experience, it’s pretty conservative. Which is good.

One thing: the number of breakers in the panel is not related to the size of the main breaker. I’ve got 68 breakers (I’m an electrician and this is my house) and a 100 amp service. It’s all code legal. Now, if I were doing it fresh, I would have put in 200 amps. Just because I can. But for six months, this house ran on a temporary 40 breaker and it never tripped.

If

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7j43k beat me to it on the total breaker capacity exceeding the main breaker size (although I thought the code limited the maximum number of overcurrent devices to 42 per enclosure).

And +1 on a new load calc being required if a subpanel is involved. There are instructions on how to do it on line, but I would strongly recommend an electrician.

The NEC isn’t the final authority, though. States can and do require a certain version of the NEC then except some requirements and add others. The state and sometimes the county or municipalty will be the final authority. Many electrical pros do not understand this, in my experience.

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Adding up the breakers current rating is not the proper way to sizes panels or main breakers. A typical 200 Amp panel for a home might have 30 breaker slots in it. If each slot had a 15 amp breaker in it, they would add up to 450 Amps. Most circuts in a home never come close to their rating. A 15 Amp breaker that feeds a bedroom might have a couple of table lamps pluged in. Current draw would be under 2 Amps when the lights are on. You would be hard pressed to load every breaker in your house to 100% and all on at the same time.

The breakers ( or fuse ) primary job is to protect the wiring in the home and prevent fires from overloaded circuts. ( the wires get hot and start a fire ) Even special breaker for ranges, dryers, and electric heat are there to protect the wiring. No one can predict what will be attached to a circut. In my home the heating manufacturer specified a 60 Amp circut, but when it’s running it only draws 46 Amps. The extra overhead of the 60 Amp breaker is there to prevent nuisance trips as the current in rush when the elements are cold is much higher.

Most homes have 60, 100, 150, or 200 Amp services installed. The service Amp rating has more to do with how old the house is. Older homes have a lower rating as that was all they needed with the electrical devices available at the time. Newer homes have larger ratings as we have more and larger electrical devises available to us. My first home had a 30 Amp service. Two 30 Amp fuses and knob and tubing wiring.

The typical electric meter used in homes has all the current the house is using passing through it. These meters are rated for 200 Amps. If you need more than that you would have the homes feeder wires passing through current transformers and their output would feed a meter designed for them. Very expensive to install.

Get someone qualitied to check your present electrical setup and make recommendations. Be careful of “licensed” electricians. In most places if want to be a licensed anythi

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Hello all,

One of the last residences I wired was three-phase.

The reason for this was because the husband was a cabinet maker and some of his equipment was three-phase.

His wife was a potter and had a three-phase kiln in an adjacent space.

There was a main-panel with several sub-panels. As I recall the sub-panel to the house was the smallest draw from the main.

With a three-phase service you can sub-panel single phases and balance the loads.

I agree three-phase residential power is an exception but not as rare as some think given the hobbies of some homeowners.

Hope this helps.

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YGW - ok, heres the ball park estimate…

This figure:

minus this figure:

equals how much you have left no matter how many power modules you need for lighting, signals, train running, etc… You only have 200amps. I presume the assundries have used half of that.

Id take the remaining 100 amps and put in six breakers:

2 for train running power, 1 for layout lights, 1 for power modules operating signals, switches, etc., 1 for your shopbench/workroom, and the last one for high amp drawing devices like the shop vac you will use to clean the Kadee springs outta your carpet floor.

You dont want to plug in a power monger like a shop vac or circular saw into the same circuit as your multi thousand dollar DCC system.

As for determining how many amps each of those 6 breakers should be, you know a regular high amp draw circuit is atleast 15amp breaker MINIMUM. Your shop with the nice air brush compressor, acme drill press and lathe should be a good 20 amp breaker.

The layout stuff could be run on 10amp breakers. Thus never allowing alot of power on these sensitive circuits should something short or over draw.

Prolly not the answer your looking for, but i never was one good at baseball.

Douglas

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Now you are fussing over HO scale amps vs 1:1 scale amps. DO NOT GO THERE!

15A breakers are gone the way of the dodo… All of your breakers will be 20 amp unless you have special ones for tools, heaters, a/c, lighting etc.

The HOUSE outlets supplying your layout should be 20A. That is the standard these days, 25 or 30A circuits would REQUIRE different kinds of outlets. DONT GO THERE… For the layout just one breaker to supply your layout.

LION has 15A fuse (old building, you see) in what was a fomer classroom. It has one outlet in the front and another in the back, and it has flourscent lighting in the room all on the same circuit.

LION added more outlets by adding a second box over the will outlet and then running conduit to power the work bench. The layout proper is plugged into this workbench source. (LION added outlets all around the facia of the layout of him, handy boxes and conduit so that no extension cordes needed to be used. Him could have used any sort of wiring, the conduit was used to provide said LION with something to grab so him could lift himself up should him have to bed down for something.)

Your circuit capacities will be determined by the box you install to power this building. 20A is sufficient for the layout, you might use a second 20A circuit for your work bench. More for any power tools (Table saw, drill press etc.) that you may have in your trainroom.

LION said him has 15A… powers trains, lig

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I’ve got a 40 slot 200 amp panel with 4 of those slots filled with a breaker that feeds the adjacent 40 slot 200 amp panel.

Ed

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Well, not exactly. While I do have a tendency to go with 20 amp circuits for various reasons including not having to stock 14 ga wire, I have found one (1) good reason to go with 15A:

It’s faster to put 14 ga wire in than 12. And it’s cheaper. And you can put more wires in a box. And for lighting (as in lighting–that stuff that emits light) there are often really fancy switch loops and the like. And NONE (well, almost NONE) of those switch loops ever take more than an amp or so. So why “upsize” wire for absolutely no reason?

So, when I’m doing those fancy open-plan abodes, it’s 14 ga for lighting, 12 ga for receptacles.

But.

If I’m doing strings of lights in a warehouse ceiling, it’ll probably be 20 amp circuits. And 277 volt, for that matter.

Ed

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Hi again YGW:

Seems a lot of people are missing the point of your question, so let me see if I can break it down for you.

  • The length of the track doesn’t dictate how many power districts you should have. You want to figure out how many operating and idling locomotives (assuming sound) will possibly be in one power district at the same time. If you anticipate a lot of activity in one district perhaps a separate booster might be in order for that district, but the total DCC system demand won’t exceed the maximum rating of the booster(s). If your DCC system and boosters add up to 10 amps @ 12 volts = 1 amp at 120 volts. maximum, and you will rarely if ever draw all of that.

  • Breaking the layout into smaller power districts makes it easier to isolate problems. If you suffer a short only the breaker for the power district where the short occurred will flip off. That tells you very quickly were to look for the problem without having to search the whole layout. Make sure the circuit breaker indicators are visible and if practical, have them in the same panel so you can see them all at once. You could wire up duplicate panels if you want the breaker status to be visible from several different locations.

  • A common way to determine where power disrticts will be is to divide the layout into geographic districts which are easy to see (or imagine) visually. Typically, yards and service areas would be one section each, and the rest of the layout could be divided into 4 or 5 or more sections, i.e. north west corner of the layout room, north east corner, south east corner etc. etc…

  • As was suggested the DCC system should not be plugged into the same circuit that will be used for power tools. You can plug other things like transformers for lighting power into the same circuit (as opposed to taking power directly from the DCC bus). One 15 amp/120 volt circuit will be way more than you will need for the DCC system.

  • Layout structural lighting is really a

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As others have suggested, speak to an electrician. Based on what you plan to do and square footage, he can estimate the power needed, and the number of circuits required to meet code.

As to your railroad, one 15A circuit will probably be more than enough.