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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 comfortable doing the things discussed here. Furthermore your local jurisdiction may have regulations or rules which differ from what we discuss here, including wiring colors, standards, techniques, etc. Seek professional guidance from someone local to you if you are unsure of anything you're doing here. Also there could be errors, omissions, or typos here. 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 as much as 2-5 amps!!

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 "too good to be true" deals on Amazon where the wire is really coming from some no-name who-knows-where.)

One thing we can say for certain is you should buy UL 1007 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

Most people buy two sizes: 18 gauge for power and 22 gauge for data. (If you are doing your own AC high voltage supply side wiring, you'll need 16 gauge for that as well.) You can always use larger wire, and in fact larger wire has less resistance, so it's "better" in a lot of cases, 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.

DC Power

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


Color AWG Purpose
🟠 Orange 22 Switch Inputs
🟣 Purple 22 Switch Returns
⚪ White 22 LED Data

AC Power


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

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

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, of course feel free to add some variation to the unique wires you need. It's probably a good idea to keep all of your coil high voltage wires blue, but maybe you use white and gray and pink or something for your driver outputs from the I/O boards. Same with switches, maybe all your switch returns are purple, but you might use a few colors beyond orange if needed. (Again check your local regulations to see if there are any limitations on colors you're allowed to use.)

Documentation Feedback? Requests? Confused?

Hi! I'm Brian, and I'm responsible for the documentation at FAST Pinball. If you have any feedback, requests, corrections, ideas, or any other thoughts about this documentation, please let me know! You can email me at Thanks!

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