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FAST Pinball wiring standards and guidelines

This guide describes wiring standards and conventions we use in the FAST Pinball community.

Wiring, high voltage, and electricity can be dangerous. Read this first!

The voltages and electricity discussed here can be dangerous and could cause property loss or death. It is your responsibility to ensure you are aware of these risks and comfortable with these processes. Furthermore your local jurisdiction may have regulations or rules which differ from what we discuss here, including wiring colors, standards, techniques, etc. Although based on broadly adopted methods, FAST Pinball does not employ Professional Engineers and this information is not professional recommendations. There may be errors, omissions, or typos here. Any pinball machine available to the general public should be reviewed by a licensed Professional Engineer in your region. Use this content at your own risk.

Wire type and gauges

It's important that the wire you select for your machine is carefully chosen to support your needs and loads. Unfortunately not all wire is the same, so you have to be careful when you're buying it, and be extra careful with really cheap wire you find online or whatever random spools you pick up at a flea market.

The most important thing to know about wire is that thicker wire supports more current. (Higher amps.) Also in the United States, where wire thickness is measured in American Wire Gauge (AWG), bigger AWG numbers are actually smaller diameter wires. 🤦

The next most important thing to remember is that even low voltage can have a lot of current, and wire diameter / gauge is dependent on current, not voltage. So don't just think, "Oh I can use skinny wire because it's just 5 volts." (Take a look under the hood of your car. Your car battery is "only" 12V but hundreds of amps, so the wires coming off of it are as thick as Tootsie Rolls!)

When you're buying wire, you need to look at what current (amps) it's rated for. (See our Guide to Fuses in a Pinball Machine for more information on this before you buy any wire.) While there are "rules of thumb" for how much current a specific size AWG wire can support, there are many factors that affect this, including whether the wire is solid or stranded, how many strands there are, the temperature, whether the wire is bundled in with bunches of other wires or free floating (called "transmission" wire versus "branch" wire), and lots of other things. These factors can affect the rated amps for the same gauge of wire by 30% or more!

Also what the wire is made out of affects things. There's stranded wire where the strands are solid copper, and then there's stranded wire that looks like copper but really it's "copper clad aluminum" (CCA) which has very different properties. (CCA is usually cheap and should NOT be used in a pinball machine. Do an internet search for "CCA versus copper wire" for scary details.)

So, like everything with the electrical portion of your pinball machine, you need to do your research and make sure you know what you're buying and that you're buying from a reputable source. (Beware of cheap wire on Amazon where people have found things like "sold copper wire" which is really CCA, etc.)

In fact, one thing we can say for certain is you should buy UL listed stranded (not solid) wire. One of the sources for wire several people in the pinball community use is Remington Industries UL1007 hook-up wire

The specific UL listing standard you select is up to you. The link above is for UL 1007 hook-up wire, which is fine. (Again, be sure to select stranded, not solid.) People also like UL 1569, which is also fine. The key is not the specific standard, rather it's buying wire from a manufacturer and seller you trust, with the UL listing you want, and the confidence to know what they're claiming is actually what you're getting. (Again, don't buy wire from Amazon.)

Most people buy two sizes of wire: 18 gauge for high current power, and 22 gauge for low current power and data. All the FAST Pinball boards align to this too, with 0.156" headers for 18-gauge wiring (up to 7A), and 0.100" headers for 22-gauge power (up to 3A) and data wiring.

If you're building your own power box, you'll want 16awg wire for your AC lines as well, though you'll only need a few feet of each color (black, white, green) for that.

You can always use larger wire than what's recommended, and in fact larger wire has less resistance, so it's "better" in that sense, though larger wire is also more expensive, heavier, and you have to ensure you can fit it into the connectors and crimp housings. (For example, you might be able to find connectors for 0.100" headers that can work with 20 or 22 gauge wire, but you probably aren't going to be able to fit 18 gauge wire into one of those crimps.)

Wire colors

While it's extremely important that you follow the guidance around wire type and gauges, within the FAST Pinball community we've also standardized the colors of wires we use.

This is more optional for you, and certainly we understand that if you have wire already which meets the technical requirements, then who cares what color it is?

But for all of our diagrams and drawings, and all the physical builds we do (which also means all of the photos and videos we create), we use standard colors. So if you haven't bought your wire yet, you might consider using the same colors for the same purposes as us so everything you build matches up to what you see on our sites and within the larger community.

18 Gauge

18 gauge wire is used for high-current (up to 7A) power and 0.156" connectors in a FAST Pinball modern machine.

Color AWG Purpose
🔴 Red 18 5V Power (high current)
🟡 Yellow 18 12V Power (high current)
🔵 Blue 18 48V Power
⚫ Black 18 DC Ground Returns (high current, all voltages)
⚪ Gray or White* 18 Control lines from coils to I/O Board driver control pins

22 Gauge

22 gauge wire is used with 0.100" connectors in FAST Pinball modern machine for both data as well as lower current (<3A) DC power.

Color AWG Purpose
🟠 Orange* 22 Switch Inputs
🟣 Purple 22 Switch Returns
⚪ White 22 LED Data
🔴 Red 22 5V (or less) Power (low current)
🟡 Yellow 22 12V Power (low current)
⚫ Black 22 5V/12V DC Ground Returns (low current)

* See section below about same color versus striped or multiple colors.

AC Power


These AC wiring colors are standard in the United States. Your locality may have its own standards, so of course follow local guidance. (Blue, Brown, and Green/Yellow in Europe, for example.)

Color AWG Purpose
⚫ Black 14-16 AC Line Power - Hot
⚪ White 14-16 AC Line Power - Neutral
🟢 Green 14-16 AC Line - Earth Ground

You will only need a few feet of each of these AC power wires (since it's only used within the "power box" section of your machine). So you might want to buy some "wire by the foot" from your local hardware store instead of a whole spool of 100 feet or whatever you find online. (If you do this, make sure you get stranded hook-up wire made for appliances, not solid wire made for buildings.)

Why do you use the same color for all your switch or coil wires? Isn't that confusing?

In our wiring standards, and in all the drawings and diagrams in our docs, you'll notice that all the switch inputs are orange, and all the driver control wires are gray. (Actually we use white in real life but that doesn't work on the web so we draw them as gray.)

But you might think that's confusing. If you have 32 switches connecting to the same I/O board, and they all use orange wires, how do you tell what's what?

First, because the FAST I/O boards are scattered throughout your machine instead of all up in the backbox, it's easier to trace a specific wire from a switch to its input. If you have to cut some zip ties to get at a wire, you can see the end you need, so it's easy to tell them apart.

But, more importantly, the reason we use the same color for everything in our documentation is because it's much easier to look at an diagram on the web and know what's what. If you had a rainbow of switch wires, it would be pretty, but you wouldn't know at a glance what you're looking at. But with a standard single color, you know any orange wire is a switch input, and any gray wire is a driver control wire.

In your actual machine, if you want to use more than the one color for those wires, that's totally up to you! We suggest not mixing ones that are nearby and obvious. For example, your 48V supply wire going to every coil is blue, 12V is yellow, and grounds are black. So maybe don't use those three colors for your driver control, but if you wanted to use red, orange, green, purple, white, pink, brown, and gray, that seems fine. Even if some colors are used in other places, they're usually different enough to keep apart. (Will you really confuse a 22ga LED power wire going from LED to LED with an 18ga driver control line going from an I/O board to a solenoid? Probably not.)

You do you, is the bottom line!

What about two-color striped wire?

In classic pinball machines, all the wire was two-color: a base color and then a stripe of a different color. That let manufacturers create 64 uniquely identifiable wire combinations out of just 8 colors. Striped wire was really important in the days when all the electronics were in the backbox since you needed to be able to identify individual wires in thick transmission bundles from the backbox to the cabinet. But in the modern era, where the FAST Pinball I/O boards are underneath your playfield, you don't need as many colors since you can just look and see which wire is which.

That said, you can buy striped wire, but in our experience, it's more expensive, and also not as practical because you might only need a few feet of each color combination which means you would have a lot of unused wire. (And wire is annoyingly expensive nowadays.)

If you want to look for random striped wire on eBay, that's fine, but make sure you're getting what you think. (Again, some sellers claim that wire is solid copper, but if you take a knife and scrape the wire, you see that it's just copper-clad aluminum.) Buyer beware!

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