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By far the most daunting part of the printer build for many is wiring up the electronics bay of the printer. But fear not, many have preceeded you on this quest!

A word on safety

You will be working with mains voltages (120 VAC / 240 VAC). Always double check to make sure your printer is unplugged and that the capacitors in the power supplies are depleted (check the status LED) before touching any of the electronics.


Working with electrical wiring and electronics can be confusing due to the plethora of acronyms and shorthands used. Here, we go over the most commonly used acronyms and shorthands within the 3D-printing community.

Connections / pads glossary

Term Description Category Note
L Live AC mains no touchy
P1 Live phase 1 AC mains no touchy
N Neutral AC mains  
PE Protective earth AC mains Not the same as ground
VAC Volts AC AC mains  
VDC Volts DC DC voltages  
VCC Voltage Collector DC voltages Derived from BJT Collector voltage
GND Ground DC voltages a.k.a. Circuit ground
AGND Analog Ground DC voltages Used for analog circuitry
VMOT Motor voltage DC voltages Voltage for stepper drivers

Electronics glossary

Term Description Category Note
Cap Capacitor Components Stores and releases energy
JST Wire terminal Terminals Japan Solderless Terminal
CSI Camera Serial Interface Connections RPi-exclusive camera connector
DSI Display Serial Interface Connections RPi-exclusive display connector
PSU Power Supply Unit Components  

Useful tools

Tool Purpose Importance Note
Ferrules Terminating stranded wire High  
Crimping pliers Crimping various terminals Medium Required for JST, Ferrules, etc
Soldering iron Soldering wire extensions etc High Better than twisting


To start you off, here are some miscellaneous tips you might need on your journey:

  • You don’t need fancy tools to do electronics wiring, but it does make life more easy.
  • Practice crimping (JST) connectors and ferrules and make them pass the “tug test”; this will save you a lot of headaches later!
  • It is good practice to stick to the wire color conventions specific to your region.
    You can of course use any wire color you want, but this may make it harder to troubleshoot later.
  • Avoid twisting wires together if soldering is an option
    Twisted wire connections just aren’t very durable or safe for high intensity applications.
  • Don’t use silicone insulated wire in drag chains
    The excess friction causes the drag chain to not work properly and wear your wires prematurely.

Make sure you’ve set the input voltage selector switch on your PSUs if applicable!

  • Selecting 220V in a 110V country will cause your PSU to run under its rated power.
  • Selecting 110V in a 220V country will cause your PSU to spontaneously have an existential crisis (it breaks).
    Voltage selector switch

AC wire color conventions

Different countries have different standards for mains wiring and the used colours, but these are the most prevalent ones you may want to know of according to the DIN 40705 and CEI/IEC 60446 standards:

Wire & cable US/Canada Europe & UK China & Russia Oceania Japan India
Live / Line black wire red wire brown wire yellow wire red wire black wire red wire
Neutral white wire grey wire blue wire black wire black wire white wire black wire
Ground / Earth green wire earth wire earth wire earth wire green wire green wire earth wire

DC wire color conventions

There is no general standard for what colours are used for what voltage node, but there are some key standard colours we like to abide by in the 3D-printing community (derived from the ATX colour coding standard).

Potential Symbol Colour Note
Ground GND black wire  
5V 5V red wire For supply lines
Signals S, Signal white wire For signals such as limit switches
12V 12V yellow wire  
24V 24V, VCC, VMOT, etc. yellow wire  
48V 48V, HT, VMOT, etc. purple wire orange wire Use a color different from 5V/24V

Choosing the correct wire type

Using smaller wires than recommended for their rated current may result in cables melting or catching fire. Always use a wire gauge that at least matches the current load!

Using appropriately sized wires ensures they can safely handle the current draw of your printer’s components. Using undersized wires will increase the wire’s electrical losses, which can lead to (over)heating, damage to the wires or your printer, or even other things. Undersized wiring is always an imminent fire hazard for this reason.

This table specifies recommended minimum wire size when using nickle-free stranded copper wires; larger wire can always be used (within reasonable limits).

The rated current capacities are a general rule of thumb. Ensure wires are never used beyond their rated specifications! This includes (but is not limited to): current rating, resistance per length, insulation temperature limit, and environmental temperature. The Standard Wire Gauge or American Wire Gauge engineering tables contain more reference information.

Application AWG Metric Max current rating
Mains / AC 18 AWG 0.75 mm² 10A @ 120/240VAC
Hotend heater 20 AWG 0.50 mm² 6A @ 12-24VDC
Stepper motors 22 AWG 0.32 mm² 4A @ 12-48VDC
Signal wires 24 AWG 0.20 mm² 2A @ 5-24VDC

Mantle types

In general, it is recommended to use stranded copper cable for most DC components. For motion components, always use a motion rated stranded copper cable, with a mantle suitable for motion applications. Good wire options are silicone sleeved cables or PTFE (teflon) sleeved cables that come at an extra cost, but are more flexible and provide less friction inside a wire loom.