Adequate Electrical Power for a Layout

[grayfox1119]

One additional note about circuit breakers, they trip under any one of TWO conditions:
1. Short Circuit.......if this occurs, they trip immediately
2. Thermal.......this occurs when you exceed the current rating of the breaker for a period of time, the greater the exceed, the shorter the time for the breaker to trip.

And as Leon has pointed out, constant overloading of a circuit, or even running very near the current limit of 20 Amps, like 19.9A, continuously, is most certainly going to degrade the insulation on the conductors. This eventually can result in bare copper wire touching wood studs or floor joists. When that occurs, the wood actually starts to turn black from the heat of the wire. That black material is carbon, the material resistors are made of. So now we have a resistor soaking up more heat and eventually you reach flash point and you have a fire.
Plan properly, have enough circuits. Your overhead lighting needs to be on it's OWN circuit, not shared with the duplex wall outlets. And you need enough circuits in your train room to handle not only your layout, but your work bench, and all the equipment that you will have, like fans to keep solder smoke away from your lungs, Dehumidifiers in humid weather, or damp basements ( high humidity causes oxidation of all metal surfaces, and that is a killer for electrical conductivity ), or humidifiers in very dry areas. Low humidity causes static electricity to build up, and this will kill electronics very quickly unless you are grounded when you touch circuit boards that have static electric sensitive components. If you stroke your cat's fur several times and draw an arc to her ears with a snap that sends her flying out of the room....you have very low humidity.

[Anonymous]

Hey Guys,

I have two twenty amp circuits in my new train room. One word: LIGHTS. 15 amps is only 15 - 100 watt light bulbs (I know there are more efficient lighting systems). If you plan to have a medium sized, well lit layout, lights are going to be your biggest load by far. While 40 amps may seem overkill, add up the number of lights you might want, you will be surprised... Add power tools, heater, etc you are there easily. I don't even consider the trains themselves and the attendant power supplies to be much in the equation. If you put in the two circuits, you never say later I wi***hat I had more power....

My two cents,

[Leon Silverman]

While I wouldn't argue with anyone saying a heater, freezer, and space heater should be on separate circuits, the reason the circuit handled all three item at once is that the circuit rating (2400 or 1920 Watts) is based on a constant draw rather than an intermittant loading. If the heater is being used, then the refrigerator and freezer have to operate for only a short time (if at all) to maintain their interior temperatures. Consequently, the average loading on that circuit remains within the allowable limit.
Sustained operation is this manner would probably dry out the insulation in a few years even though there is not an immediate problem.
This intermittant electrical loading is why the PRR GG1's could generate temporary ratings of 10,000 HP for short bursts of acceleration while being rated at a continuous draw of only 4650 Horsepower.

[Anonymous]

Separate circuits for lights and wall outlets is highly recommended. If you blow a circuit by plugging in a tool while your under the layout you will still have lights so you can find your way out (and a safe place to set the HOT soldering iron!)

I believe in separate ciruits for lights and wall outlets in all rooms.

Good luck,

-OT

[Anonymous]

Grayfox pretty much hit the nail on the head with the Ohm's Law formulas. As he stated, 1920 watts on a "20A" circuit is a safe loading. With our Model railroad systems, we are usually running a maximum of about 8 amps to supply track power, at a voltage of up to 20 volts. When you add this up, it only amounts to 160 watts, plus losses in the power supply transformer, so 200 watts would be about the maximum here. This could be fed from a 2 amp circuit at 120 volts. Unless one has a huge layout, or numerous power supplies (or boosters, etc.), a single 20A circuit should be more than adequate. Again, if providing additional lighting, you may want a separate circuit there. One 20A circuit for layout power is more than enough for just about any home layout.

Randy,
The point grayfox was making about the loading on your circuit actually is correct. If all three devices were to try to start at exactly the same time, your circuit would almost certainly have tripped (due to higher starting current on the compressor motors). The odds of this happening would be high enough that you would probably never see it happen in your lifetime. As for the heater not drawing what it claims it draws, you must keep in mind that 1500 watts is the maximum load. If it's controlled by a thermostat, it may be shutting back off again before it gets to the point where it reaches the 1500 watt level. If it's a selector switch control (i.e. low, medium, high heat), only the high heat setting would draw 1500 watts. The other settings might be 500 and 1000 watts, for example.

-Joe

[rrinker]

I honestly could not tell you ONE person who has a freezer in their basement or garage and has it on a DEDICATED circuit.
Have to check the freezer plate, or maybe the heater is incorrectly rated, because the breaker doesn't trip and it's not even warm, so it can't be loaded with anywhere near capacity. It all started out as a mistake anyway, I told the electrician to wire the outlets on the two different walls as two different circuits, did not even realize they were the same until a second heater was plugged in and it DID trip the breaker. The heater has been moved.
Two 1500 watt heaters ALONE should not operate one a single 20 amp circuit, however, they did. Until the freezer kicked on. I'm guessing the actual draw is somewhat less than the 1500 watts, but I don't have a clamp-on meter to measure high current AC. Maybe '1500W equivalent" which is, obviously, bull. Either it takes 1500 watts or it doesn't. You can't take 1000 watts and make 1500 watts of heat from it.

--Randy

[grayfox1119]

OK guys time for a little basic electricity knowledge: First of all, house voltage today is not 110V it is 120V.

There are only two formulas that you need to know to figure out if you have enough power on one circuit, or , to just understand the basics of any use in your home. We will just talk about 120V, not 220V here because we don't run trains on 220V

E=IR and P (power in watts) = EI

All you need to do is add up all the wattages used by whatever you have plugged into the outlets on a given circuit.

One 20 Amp circuit will provide 120volts (E) X 20 Amps (I) = 2400 watts of power. The standard U.S. electrical code de-rates 20% as a SAFETY factor, when planning the load on any branch circuit, so that means you can safely use 1920 watts.
If you don't know the wattage of your equipment, you can usually find the current drawn by each device, so add these up and make sure you are not over 18 Amps used for a 20 Amp circuit.

Now this is for Randy. You have a 1500 watt heater, a freezer, and a dorm size frig on ONE 20Amp circuit? If the heater is ON, you have 1500 watts being used. Now the Freezer compressor kicks ON, it can easily draw 5 amps when starting, so that is another 600 watts. If the frig kicks ON, it will initially draw about 3 amps, so that is another 360 watts. The total watts being consumed is now = 2460W !!! You are in serious trouble friend!! Also, the code strictly says that all large appliances have to be on their OWN circuit. That means a seperate 20A circuit for the Freezer. The dorm size Frig , if it is one of those 2 foot by 3 foot things, you can get away with being used on a shared circuit. If you ever have a fire and it is traced to this violation as the cause....you probably will not collect on the insurance.

Bottom line, one 20A circuit is fine for running trains DCC or DC. If you also have a workbench in this room, and on the same circuit, then you need to be careful what you plus into the outlets, add up the power being used and make sure you are OK.

Lights should be on their own 15 Amp circuit, and not part of the 20Amp circuit.

[jrbernier]

I have 1 20 amp dedicated circuit for the train room(20'x25'). This is split into two circuits, each controlled by a wall switch:

o - one goes to all of the wall outlets(every 6' along the perimeter of the layout). This
powers all of the track power, and provides outlets for power tools.
o - The second line goes to the 10 4' twin tube fluoresent fixtures over the layout.

There are another 3 fluoresent fixture(one in each isle) that run off of the family room breaker and provide lighting in the layout room when not running trains. I think two 20 amp circuts are way too much. My garage/shop have a 15 amp and a 20 amp circuit; the 15 amp powers 5 large fluoresent fixtures, a 500 watt yard light, garage door opener, fan in the gas furnace out there, and a night light. The 20 amp circuit powers all of the 'belt rail' outlets that the power tools plug into, and an outside outlet that the Christmas lights are powered from. I think a dedicated circuit is a good idea, but a single 20 amp circuit is more than enough. And yes I have a Digitrax Chief, Booster, and several other power supplies running off of that 20 amp circuit, with over 300' of trackage.

Jim Bernier

[dave9999]

QUOTE: Originally posted by KenLarsen

QUOTE: Originally posted by dave9999

...This electrician friend of yours is not charging for his services, is he? Sounds like he is trying to make a few extra bucks.[:D]
Dave

In fairness to the Electrician, he's actually a friend and neighbor. Yes, I have hired him in the past bit it was well worth it - he does excellent work. He's not a "gouger".

Ken,
I was just kidding around about the electrican(note the smiley). But seriously,
I would listen to him before me anyway... I'm not an electrician. I am only speaking from my experiences
with running high amp power tools without
problems. Good luck, Dave

[dave9999]

QUOTE: Originally posted by Big_Boy_4005

QUOTE: Originally posted by dave9999

I can run an air compressor(construction type, not a little airbru***ype) and a circular saw at the SAME
time on a 15 AMP circuit without tripping a breaker. I seriously doubt that your layout will require TWO
20 AMP circuits. This electrician friend of yours is not charging for his services, is he? Sounds like he
is trying to make a few extra bucks.[:D] Dave

Hey Dave, do the lights dim when you start the saw, or when the compressor kicks on? Those events are the times when the greatest load is placed on the circuit. Once they are running the load goes down considerably.

The curcuit has only outside outlets. No lights. And of course the greatest load is on startup. I was only trying to illustrate the point that a model railroad does not draw the amps to worry to much about a dedicated (much less two) 20 amp circuit. Dave

[rrinker]

I have a 1500 watt heater, a 23 cu. ft. freezer, and one of those little dorm fridges all on one 20A circuit, it is NOT overloaded. And I was running my soldering iron off the same circuit for a while. The 1500 watt heater has been moved to a seperate circuit now.

You can run a lot of Lionel trains on 4 ZW's, and 4 ZW's would in no way overload a 20A circuit.

--Randy

[Don Gibson]

Having your layout on a separate circuit is a nice idea. Cnceivably it could cut down on TVI when running trains. (Motor's and wheels spark when running).

A standard household circuit (110V) is 15 amps. I doubt your RR will uxe 3 amps continuous or 6 - 10 amps instantaneous peak..DCC is 4 - 5 amps.

What WILL consume power as an Electric heater to heat a cold basement, when you are operating.

[Anonymous]

QUOTE: Originally posted by dave9999

...This electrician friend of yours is not charging for his services, is he? Sounds like he is trying to make a few extra bucks.[:D]
Dave

In fairness to the Electrician, he's actually a friend and neighbor. Yes, I have hired him in the past bit it was well worth it - he does excellent work. He's not a "gouger".

But he doesn't know model trains....except that they are powered by electricity.

He is apparently counseling extreme caution - doesn't want to see my layout blowing circuit breakers all over the place. I figured my existing infrastructure was OK, but figured I might as well get a second opinion...maybe a third...and a fourth...I've burned myself too many times before, by rushing into things without seeking advice of those who have "been there"[banghead].

Thanx everybody, for the feedback!

[Big_Boy_4005]

QUOTE: Originally posted by dave9999

I can run an air compressor(construction type, not a little airbru***ype) and a circular saw at the SAME
time on a 15 AMP circuit without tripping a breaker. I seriously doubt that your layout will require TWO
20 AMP circuits. This electrician friend of yours is not charging for his services, is he? Sounds like he
is trying to make a few extra bucks.[:D] Dave

Hey Dave, do the lights dim when you start the saw, or when the compressor kicks on? Those events are the times when the greatest load is placed on the circuit. Once they are running the load goes down considerably.

As for the electrician, I think his problem is that he just hasn't "played" with trains lately.[swg]

[Big_Boy_4005]

Well, I guess it depends on a couple of things as to whether you would need that much power. First what kind of trains you're running, and second how large your layout is.

Running old trains with their less efficient motors, like post war Lionel, plus all of the associated accessories, on a good sized layout (500 sq ft or larger) could put a real dent in a 20 A circuit. Personally, I will have two 20 A circuits for layout power, but I am running 3 rail O, and have over 2000 sq ft of layout.

Running HO or N, even at twice the layout size, probably wouldn't come close to taxing a single 20 A circuit.

Layout lighting should be considered seperately.

[dave9999]

I can run an air compressor(construction type, not a little airbru***ype) and a circular saw at the SAME
time on a 15 AMP circuit without tripping a breaker. I seriously doubt that your layout will require TWO
20 AMP circuits. This electrician friend of yours is not charging for his services, is he? Sounds like he
is trying to make a few extra bucks.[:D] Dave

[retsignalmtr]

you don't need two twenty amp circuits to run your layout. the existing circuits should be enough to power it. if you start tripping the breaker or blowing the fuses if you have those then you may want to upgrade to 20 amps. as was previously mentioned you may want to have a wall switch to kill the entire layout when you leave the room. # 14 wire is for 15 amps and # 12 is for 20 amps and you can't just change the circuit breaker without increasing the wire size. i've just bought the digitrax empire builder and i will be using the same circuit as my tv, computer and several lights without any problems.

[rrinker]

TWO circuits? wow.... that's probably a bit overboard. Even if you add complete signalling and illuminate every structure on the layout, you're not going to need 20 amps on the AC side to power it all. Hopefully one of these new circuits was set up with a wall switch near the room entrance? That way you can always ensure ALL electrical power to the layout is shut down when you leave - including that soldering iron you THOUGHT you unplugged. A good safety feature.
The only reason I could see to having more than one dedicated circuit for the train layout is if the distance and code dictates having more receptacles than is allowed on one branch circuit - ie, code says receptacles every x feet, no more than 10 per circuit, and your room size means you need 15 receptacles to use the code spacing, then it would require two circuits (I'm making up the numbers here, but there are actual numbers for this in the NEC and possibly in your local code as well). I'm probably in the same boat, if I put receptacles at proper distance from one another around the entire train area, I will probably need two circuits just because of the total number of receptacles, not because of the current draw. I know I need additional lighting circuits, the one already in the basement can not handle the number of light fixtures I need to install.

--Randy

[Anonymous]

An electrician friend of mine is trying to convince me to install two separate 20-amp circuits for powering my layout and accessories. I think this seems a tad extreme (BTW, the guy hasn't had any trains of his own in over 40 years!). The layout in my previous home worked fine on the pre-existing outlets. But my new layout will have more track (~200 linear ft) and have DCC (Digitrax Chief).

Any reason why I can't just use my existing outlets here as well?