Hey, if this has been covered at length, please let me know so I don’t carve up more bandwidth here.
Should I dedicate an entire 20 amp circuit?
My layout will be 8’ X16’ and I will use DCC, probably 15 to 18 powered turnouts, lights in structures and streetlamps, 4 to 6 locomotives max at any time.
Also, I’ve just finished adding significant extra lighting on an existing circuit so room lighting is already taken care of.
-Dave [:o)]
You won’t NEED an entire 20 amp circuit. But you might want to put one in - and run the power via a wall switch next to the switch for the room lights. That way, when you leave the room, you can be SURE everything on the layout is turned off - power supplies, soldering irons, etc. Even better - make sure to use a switch with a pilot light so it’s red when the power is ON. Total power for a bunch of power supplies and such won’t even tax a 15 amp circuit, let alone a 20, but you WILL need lots of outlets.
–Randy
Here is how you can determine what you will need:
A 20 amp circuit uses #12 gauge wire, and is obviously rated to carry 20amps or 2400 watts. The eelctrical code in most if not all States, uses 20% as a safety de-rating factor, so that would give you 16 Amps and 1920 watts.
All you need to do now, is add up your power being consumed by all your devices, and see how close you come to your safety factor maximum.
If you are too close to your maximum , I would add another circuit. If you plan to share ONE 20 amp circuit with another room, I would add another DEDICATED 20 Amp circuit for your train room, you do not want other appliances causing voltage spikes and drops when they turn On and OFF.
You didn’t say what scale - so I presume HO. I would go with 20 amps, the reason - you may decided to add options you never planned on now, or even thought about. Tastes in layouts have a way of changing as you become more experienced and more knowledgeable in the hobby.
You never know, you might be interested in computer running of some of your trains, computer running of trains in and out of staging. You might want extensive signalling, and animation, and… and … and…
Its the easiest now to add what you think you are going to need down the line. I would not have the lights on the same line as your main power serving the layout - if you can help it. In my situation, part of my layout is independent power with two lights on that electrical circuit.
If possible, try to have your room lighting and outlets on separate circuits. That way, if something were to short out, you wouldn’t be left in the dark.
the 20 amp will be sufficient…remember also that you are probably going to use a lot of power tools in the train room so the extra 5 amps is a plus…I’ve had breakers trip using a 15 amp breaker especially when i turned on the electrical motor driven air compressor for my air brush work…Chuck
Maybe, Chuck… I do all my sawing out in the garage to keep the mess away. The only power tools being used in the train room are a Dremel and my 18V DeWalt drill/driver.
Still, it’s really not much more to run 20 amp circuits so it makes sense to do so regardless. Another tip - buy the heavy duty receptacles, not the ‘consumer grade’ ones. I am having to replace ALL of the receptacles in the upstairs part of the house because it was originally built with some cheap grade PLUS the previous owners obviously mistreated many of them.
–Randy
If you’re planning on lighted structures and streetlamps - definitely the 20 amp. Its always amazed me, but its a fact that you’ll consume an amp of electricity for every ten to fifteen of those little lights.
Excellent and useful advice from all! Much obliged.
Yes, HO scale and power tools will be limited to Dremel, possible air compressor, battery rechargers for cordless stuff and a compound miter saw.
That, plus the requirements for powering the trains.
-Dave
Three things to keep in mind.
While you may not actually use much power, you will have a lot of “things” plugged in at once. Power supplies, tools, soldering irond, drop lights, ect. Its important to not start out having to use multi taps at outlets or having extention cords running everywhere. Therefore, don’t be skimpy with the outlets. I made mine such that each outlet is a quad receptcle ( 4 plugs can be connected at once).
To clarify, a receptacle is a connection point for one plug. An oulet is simply a location to connect into the electric system in your house. An outlet can have any number of recptacles, 2 being the normal. The terms are used interchangably, but they mean very different things.
The national Electric code limits the number of recptacles that can be on a single circuit by using the formula of 80 VA per recptacle . For this example only, VA is equal to watts. So 20A x 120 Volts = 2400 watts. 2400 / 80 = 30. Thats 30 recptacles. A typical outlet is a Duplex receptacle (2), so that counts as 2. A quad would count as 4.
Lighting should always be on a seperate circuit.
In a train room setting, all the recptacles of all the outlets ( top and bottom ) should be controlled by one master switch that gets turned off when you are done with the layout. Power supplies overheat, soldering irons get left on, drop lights are left against plastic. It happens. In 35 years as a fireman, iv’e seen all this happen.
Neal
That’s on the output side. The input at 120VAC to drive a 1amp, 12V power supply would be miniscule. Closest thing I have handy - power adapter for my digital camera. Output is 7VDC, 1.8A. Input draw at 120VAC? .23A.
–Randy
Fireball XL5,
I remember the puppet show well. It was one of my favourites as a kid. Thanks for the advice.
Randy,
Wouldn’t I be driving little streetlights and structure lights from a separate power pack? so it will have a maximum draw won’t it, regardless of how many lights I have? (sorry, no formal electricity edukashun here)
-Dave
All good ideas. I like Fireball’s idea of quad outlets. Multi-tap outlets and extension cords are not good, although a necessary evil at times. At least it will let you leave things plugged in and turned off when not using them instead of having to crawl around unplugging some things in order to plug in others. The electrical codes specify that a room should have an outlet every so many feet around the walls–I think it’s 8’. That’s a minimum, and builders go for minimums to save costs. I would put my outlets closer together to get more of them, and I’d use 2 circuits, with alternate outlets on alternate circuits.
It’s an excellent idea to have a master switch to turn everything off when you leave the room. I have a master switch for each of my two workbenches which controls the light over the bench and the outlets on the bench. I flip the switch, the light goes off, and I know that everything on the bench is unpowered. Just keep in mind that the standard household light switch is rated only for 15 amps, and if you’re passing its maximum current through it, it will wear out over time.
You might want to consider running a 20 or 30 amp, 220 volt circuit into the layout room and installing a sub-panel with breakers for the individual circuits in it. That would require some planning and should be done by a licensed electrician.
Another thing to consider is one ceiling light in the room which is not on any of the other circuits. That way if something pops the lighting breaker for the room, you’ll still have light. It would have to be run through a separate on-off switch by the door–you’d have two light switches for the room.
One thing I’m surprised that no one has mentioned so far is to get a wiring permit from your local authorities. This is mandatory when doing any new electrical wiring or modifying existing wiring. If you’re doing the work yourself, you’ll have to prove to the people who issue the permits that you know what you’re doing, and after t
20 Amp circuit. Use a GFCI breaker on the circuit, costs about $30 more than a regular breaker, but it protects the entire circuit and doesn’t wear out, unlike the GFCI outlets that builders like to use (cost again). Think very carefully about WHERE you put your outlets, especially with regards to accessing them once the benchwork is in place. Put a dedicated 4 receptacle outlet at your workbench. One receptacle for your soldering iron, one for your task lighting, one for your powerpack, and one for your boombox. If you decide to use 2 alternating circuits (overkill for a train room, but we are, after all, guys), DO NOT use a common return (i.e., split a 240v circuit), or you won’t be able to use the GFCI breaker. (DAMHIKT!).
Nope, input current draw is proportional to the output load. In my example, i would ONLY draw .23 amp from the AC side if the output side was loaded at the maximum of 1.8 amps. You can also see the inefficiency in the power supply - 7.0 volts at 1.8 amps (sticking with my AC adapter example here) is 12.6 VA. Input of .23 amps at 120V is 27.6 VA. Where’s all the extra go? Losses in the components and mostly as heat.
When you step down voltage, the current goes up, minus losses int he transformer and rest of the circuit. Losses generally show up as heat, that’s why a power supply gets warm under load. If you disconnect the output fromthe circuit, like turning off all your lights, the only current drawn on the primary side will be a minimal amount dependent on the transformer windings. I was going to use a computer as an example, but modern computers almost all have a constant supply for the wake-up features and thus are always drawing a little current even when turned off. But take my camera adapter. If I do not connect the camera, it will only draw a miniscule amount of current - not the .23 amps. It will ONLY draw the .23 amps if I load the output to the full 1.8 amp capacity.
Clear as mud?
–Randy
Bikerdad, you are so right on the common neutral. I saw one house where the new kichen wiring used two circuits at each kitchen countertop duples outlet by removing the jumpers on the outlets. This was very common up until GFCI’s came on the scene. You cannot use a common return on two seperate 120V outlets across a double pole breaker, the GFCI’s do not like this at all.
Dave,### make surethat you have #12 gauge wire if you tap into another circuit to run your 120V outlets. It is far better to run a DEDICATED circuit to your train room. As for lighting, as mentioned already, this should be on it’s own circuit, and should be #14 gauge wire. That is standard for all new home and most older homes. If in the basement, you definetly will have to have GFCI outlet, or, as also mentioned already, a GFCI breaker that is right in your house main panel ( or sub panel if you have additional load center/s).
The code on doing your own work varies from state to state. In my state, I, being the homeowner, can do my own work, but I have worked in the electrical/electronics world since I was 18. If you do your own work, check with your town/city wiring inspector to see what you need to do…it is no big deal, so go see him/her, it can save you a lot of pain possibly.
I am building a train room now, 11 feet by 26 feet in an enclosed room in the basement, and I have placed duplex outlets every 4 feet. Plastic outlet boxes are dirt cheap, and a roll of 250’ of #12 wire is about $31 at HD, so don’t skimp, it is a royal pain to add later, and you never seem to have an outlet where you need one .
Good luck Dave,
[:)][:)]
Code requirements dictate that outlets be spaced no more than 12 feet apart. If you decide to go the GFCI outlet route instead of the circuit breaker, the GFCI has to be on the first outlet fed by the circuit breaker. If you place this outlet near the entrance to your room you can turn off all the power with the test switch on the GFCI. I cannot tell how long these GFCI outlets will last, since I only installed my a month ago, but you can probably buy three GFCI outlets for the price of one GFCI circuit breaker.
The room is an old coal cellar in the basement of a century home so it’s fieldstone walls, no studs or drywall, exposed floor joists above, poured concrete floor. All existing wiring has been routed or attached to these floor joists above.
I do not want to install studs and drywall to hide the fieldstone as the fieldstone will need cement repairs over time.
Any problem running a new circuit and securing receptacles to the ceiling joists? I thinking of a couple above the work bench area in particular, 3 or 4 around the layout. There are already two receptacles in there from the previous house owner.
There should be no problem attaching wires or outlets to the floor joists. However, I would check the condition of any circuits or pipes already up there. I suspect that if you run your fingure over the tops of them, you will discover a layer of dust. This is generated by people walking on the floor overhead. This is why you see the recommendation for sheetrocking or putting in a suspended ceiling.
If you don’t want to stud and sheetrock the walls, then run your wires along the joists to the wall and then drop down with conduit, either pipe or flexible, to outlets mounted in boxes attached to the wall. Some appliances have only a six foot cord, or shorter. Plugging them into the ceiling will not allow them to rest on the floor.
I think eventually you would regret putting everything on a single circuit switched to kill everything. Sure it means you’ll never leave a hot soldering iron cooking but it also means you’ll never plug in a clock, or a battery charger or a night light or an electronic air freshener, etc.
A hard wired smoke detector is a good consideration to any new room wiring project, whether required by code or not.
Wayne