Electrical Equipment



There are the three use-cases for electrical wires [3]:

  • Hot or Live = This is the source of electricity. Handle this wire with caution. It is recommended to disable the power source, if possible, when handling this wire.

  • Neutral = This completes an electrical circuit. It will only have power if a hot/live wire is connected.

  • Ground = For when the power may be unstable, power is redirected through this wire and literally into the ground to dissipate the energy.


Wires have two physical types [4]:

  • Solid = A single piece of wire.

    • Easier to solder.

    • Less flexible.

    • Easier to break.

    • Easier to insert into holes and terminal connectors.

  • Stranded = A collection of smaller wires combined.

    • Harder to solder.

    • More flexible.

    • Harder to break.

    • Harder to insert into holes and terminal connectors.


A gauge is how thick a wire is. The lower the number, the bigger the thickness. Here are recommendations for what gauge wire to use based on the project:

  • 22

    • Breadboard, Arduino, Raspberry Pi, and other single-board devices. [4]

  • 18

    • House lights. [5]

    • Small appliances. [5]

    • Speakers. [6]

  • 14

    • House in-wall electrical wiring. [4]

    • Speakers that require high power consumption and/or long wires. [6]


Each country has a different standard for the purpose of each colored wire. In the United States of America, these are the standards [2]:

  • Hot

    • Black

    • Blue

    • Brown

    • Yellow

    • Red = High voltage up to 240 volts.

    • Orange = Very high voltage up to 480 volts.

  • Neutral

    • White = High voltage up to 240 volts.

    • Grey = Very high voltage up to 480 volts.

  • Ground

    • Green

    • Bare wire (no covering)


A relay is a switch that controls power being sent through a wire or circuit. It is either normally open (NO) or normally closed (NC) when there is power sent through a contact in relay. When there is no power through a contact, a NO gate will turn off and a NC gate will turn on.

There are two types of relays: electromechanical relays (EMR) and solid-state relays (SSR). EMR uses magnets to move a physical switch. SSR uses circuits to direct electricity.


  • State of the relay is more reliable.

    • It is either on or off.

  • Requires more power to change the state.

  • Slower switching.

  • More likely to break.

  • Replaceable parts.

  • Moving parts.


  • State of the relay is less reliable.

    • It is somewhere between on and off but leans towards one or the other.

  • Requires less power to change the state.

  • Faster switching.

  • Less likely to break.

  • Non-replaceable parts.

  • No moving parts.




  1. “How Relays Work.” Galco. Accessed September 24, 2021. https://www.galco.com/comp/prod/relay.htm

  2. “Wiring Color Codes Chapter 2 - Color Codes.” All About Circuits Electrical Textbook. Accessed May 8, 2022. https://www.allaboutcircuits.com/textbook/reference/chpt-2/wiring-color-codes-infographic/

  3. “Electrical Wiring Tips: What is Hot, Neutral, and Ground.” Roman Electric. Accessed May 8, 2022. https://romanelectrichome.com/electrical-wiring-tips/

  4. “Stock Up on Wire for Your Electronics Projects.” dummies. March 26, 2016. Accessed May 8, 2022. https://www.dummies.com/article/technology/electronics/general-electronics/stock-up-on-wire-for-your-electronics-projects-180328/

  5. “Fix a Lamp Cord.” Family Handyman. August 28, 2019. Accessed May 8, 2022. https://www.familyhandyman.com/project/fix-a-lamp-cord/

  6. “What Size Speaker Wire Is Right? The Right Gauge, Type, And More.” Sound Certified. April 10, 2022. Accessed May 8, 2022. https://soundcertified.com/what-size-speaker-wire-guide/