What gauge wires should I be using for Power buses, Track power, lights and accessories?? I hear that I should be using 12 AWG for power buses, 16 AWG for track power, and 18 AWG for lights and accessories. I know the minumum is 20 AWG. What is the noticable difference between using 12 and 20 AWG wires?? Thanks.
For short runs with low current draw, say under 8’ and lights probably not noticable, on long runs or high current demands like locos and some accesories very noticable. I have an insulated part of the track that is made up by a 20g wire. The train slows a lot in this section of track.
Jim
So, you think my numbers are correct on the AWG of the wires for each application?
Where can I buy 12, 16, and 18 AWG wires in Bulk?? I mean for a reasonable price. Because I think I have to upgrade all my wiring to 12, 16 and 18 AWG wires. 20 AWG just isnt cutting it no more. But, my 20 AWG is good up to 48 volts, thats what made me buy them, cause I figured my Z only puts out 25 Volts max. There is no way I can burn out this wire or could I?? Thanks.
The size of the wire determines how much current the wire can safely carry (“ampacity”) and how much voltage drop there is between the transformer and the load. It has nothing to do with the transformer voltage. Practically anything that might be used as insulation will withstand 48 volts.
The ampacity also depends on the room temperature and how many wires are bundled together; but reasonably safe values are:
10 AWG 30 amperes
12 AWG 20 amperes
14 AWG 15 amperes
16 AWG 10 amperes
18 AWG 7 amperes
20 AWG 5 amperes
Notice that the ampacity doubles every 4 wire sizes. You should have overcurrent protection at a current no greater than the ampacity of the wire you are using.
Another consideration is voltage drop. The resistivity of various wire sizes is approximately
10 AWG .001 ohm/foot
12 AWG .0016 ohm/foot
14 AWG .0025 ohm/foot
16 AWG .004 ohm/foot
18 AWG .0063 ohm/foot
20 AWG .01 ohm/foot
Multiply the resistance by the current and you have the voltage drop. Keeping the voltage drop reasonable (well under a volt) is a reason why you might want to use heavier wire than you need for safety. The track itself is equivalent to about 16 AWG in reasonable condition.
There is no difference in the electrical performance of solid versus stranded wire.
You can easily burn out wire as heavy as 16 AWG with a type Z. You can burn out much heavier wire with a Z if you connect it between two of the A, B, C, or D terminals.
How would I know how many Amperes my trains are putting off?? I just dont think my 20 AWG is good enough. Would it be better if I went to 12 AWG for power buses, 16 AWG for track power, and 18 AWG for lights and Accessories?? I just dont think I am getting full power from my transformers using these small wires. I tried Home Depot, Lowes and a few others, none of them have solid strand wire that is 12, 16 or 18 AWG. What kind of wire do you use?? And where can I find some? thanks.
try parts express. http://www.parts-express.com
Its not the trains. Its the Max out put of your transformer. If something were to short or you had a train derail this would cause the transformer to put out its max ( amps) . Proper size wire will keep itself from being overloaded and damaged before the breaker or fuse shuts things down.
Five amperes is what I generally assume that a train draws. Some draw more, some less. If you use 20 AWG, you should have external circuit breakers or fuses rated at 5 amperes. I use type Z transformers, which have 15 ampere circuit breakers, and stranded 14 AWG wire. You should be able to 10, 12, and 14 AWG, solid or stranded, in a variety of colors, with 600-volt insulation, at Home Depot and Lowes. Look for “building wire”.
For turnouts, signals, and such, I use 18 or 20 AWG 10-conductor thermostat cable.
I was thinking of going with 10 AWG for power buses, and 16 AWG for the track power, lights and accessories. All color coded to make it easy. Is that okay??
10 awg is a bit of overkill, unless you have a VERY large layout. 12 ga. will do just fine for most layouts. 16 ga. drops from track to main busses is fine. For a “standard” 12’x 12’ room layout, I reccomend 16 ga. extension cords. cut off plug & jack, you have 15 ft of very usable wire, and they are lots cheaper than buying in bulk. Color coding is also a very smart idea. I use colored electrical tape, colored cable ties, and stick on address labels that I write on.
I am having second thoughts on buying all new wiring. Bottom line is it will cost me $250.00 in new wiring for my whole layout. I figured, I only have 1 loco running at one time, I have (12) 022 on fixed voltage, with their lanterns on bright as well as the controller’s bulbs. Also, I have none of my accessories on, unless I want to use them. But, then again I only use one at a time. The biggest loco I have is prolley my dual motor F3’s or FM’s. I am guess they pull 5 or 6 amperes at most. So I am guessing my 20 AWG should be good enough. But hey, nothing beats $3.97 for 65 feet of solid strand wire. I have not noticed any problems or wires getting hot or anything. But, this layout is only up during Oct to Feb. But, when I build my permanant layout when I am older, I will make sure to use bigger wires. I think I should be fine. Thanks for all the help.
“If you use 20 AWG, you should have external circuit breakers or fuses rated at 5 amperes.”
It’s been a few months since I bought wire, and I know copper prices have gone down since then, but you should be able to buy a few thousand feet of #14 for $250. Unless you have a huge layout, I think someone either misunderstood what you wanted, mis quoted the price, or tried to rip you off.
Another way to save money on your wiring is to try to buy the reel ends from your local Home Depot or Lowes, etc. Once a spool gets so empty, nobody will want to buy it, as the wire isn’t long enough for most household uses. Sometimes they’ll sell the last of it for a reduced price. Doesn’t hurt to ask.
If you do need 500’ of wire, but you want it in different colors, you can buy a 500’ spool of whatever color you think you’ll use the most of (preferably a lighter color such as white or yellow). Then go to an auto parts store and buy a few cans of vinyl dye (it’s a spray can). Peel off the amount of wire you need in whatever color, paint it, and paint the other side the next day.
Just a few ideas; hope they help,
J White
My wiring book says that for lights and accessories, 20 AWG is okay. So now that eliminates my 022 switches, lights for houses, 71 lamp posts, and all my accessories. But, I think I will replace my power buses and track power with 16 AWG, just to play it safe. I will need about 500 feet for all that. Stranded is what I think I will end up getting. Thanks.
All they had at Home Depot was stranded or solid 14 AWG building wire. Thats what I need. They did not have any 16 AWG building wire. But, 14 AWG is even better and the price is great!! $20.00 for a roll of 500 Feet. I guess copper is at its cheapest price ever. Oh well. I am gonna go back today and buy a 500 feet roll of red 14 AWG wire. The question is: Solid or Stranded?? I bought some spade terminals for crimping. Do the spade terminals work with solid wire?? I know they will work with stranded, just never tried them on solid wire. Its been a while since i used spade terminals though, But, how exactly is the right way to crimp the wire? The spade terminals has metal sleeve and what looks like plastic over that metal sleeve. Does the wire go into the metal part of the sleeve or not? Do I crimp just the plastic part or the metal and plastic part together?? Thanks.
Solid and stranded both have their pros and cons. I think stranded would work better for you, as some of your train items willno doubt have terminals that a #14 wire will not fit under, When you run into that you
simply snip off a few strands or use one of your fork terminals.
As for your crimpers and lugs, the wire goes into the metal sleeve. When you crimp, you’ll be crimping the plastic and the metal. If you look at the metal sleeve, you see that there’s a split in it running lengthwise. When you look at your crimpers, you’ll see that one side of the jaw is rounded,and the other side is rounded with a small nub in the center. Your connections will be tighter if you line up the side on the crimper without the nub with that slice on the terminal. If you happen to have a pair of crimpers that don’t have that nub, it won’t matter where that slice is on te terminal.
Hope this helps,
J White
P.S. By the way, #14 is the smallest building wire allowed, so most home improvement centers won’t sell #16 or smaller except perhaps by those really expensive 50 foot spools.
I was about to give up on you; but I’m glad to hear that you’re going to use 14 AWG now.
Houses are not allowed to have circuits smaller than 15 amperes; so the house’s circuit breakers are rated at 15 amperes, just the same as the one in your type Z transformer. It is illegal to use smaller than 14 AWG on a 15-ampere circuit. If you used 16 AWG, you could have a fire, whether in your house wiring or on your layout, if the load draws more than the approximately 10 amperes that that wire can handle, whether it’s too many things plugged into the circuit, a heavy train, or a fault like a short circuit or a derailment. That is why there’s no such thing as 16 AWG building wire: It is illegal to use it in a building.
If you’re buying a roll of one color, you might be better off with white. That way, even though the wires themselves are not color coded, you can easily mark the ends with color. Electricians commonly do this when they have to.
You need to buy a crimping tool. They are not expensive and usually can also strip wire and cut screws to length. There are three places to crimp the three common sizes of lugs. You should be using the medium size, with blue plastic. Strip the wire, no more than 1/4 inch. Stick it into the barrel as far as it will go, so that the wire’s insulation butts against the metal and the plastic overlaps the wire’s insulation. Then crimp at the middle of the metal barrel.
Solid or stranded is purely a matter of convenience. They are electrically identical. I use stranded. You can crimp terminals to either. You can also solder the wires to the lugs if you remove the plastic insulation. At the voltages we use for toy trains, the insulation is not really needed for protection from electrical shock.
So, you are saying that because I used 20 AWG for all my wiring, I might have started a fire or burned up some wiring inside my house, inside the walls or on the layout??
I just got back from Home Depot, I bought 500 feet of 14 AWG solid wire and I have 75 spade terminals for crimping. I have a crimping tool and will use the blue dot, the one in the middle of the 3 of them. My spade terminals are also blue, good.
I bought Red colored 14 AWG gauge wiring, so I know they are Power Buses and Track Power.
Thanks for letting me know how to crimp, its been a while. I dont think I wil solder the wires. Thanks.
I am saying that, if the electricians who wired your house had used 20 AWG or even 16 AWG, that might have (probably would have) started a fire or burned up your house wiring by now. Your transformer can deliver the same current to your layout as your house’s circuit breakers can to your house; so you should be (and now are) using the same size wire that they (let us hope) used for your house. So, if your transformers’ circuit breakers are in order, your layout wiring is unlikely to burn out or start a fire on your layout.