How a house is wired lesson plan
From the service and the meter to the panel, branch circuits, hot neutral and ground, three-way and four-way switches and GFCIs, all on low-voltage models you can break safely.
Objectives and materials
By the end, students can
- Two legs and a neutral, and the meter that counts every watt hour.
- Breakers, branch circuits and the three wires every circuit runs.
- Switch loops, three-ways and four-ways, with every flip checked.
- What an outlet carries and how a GFCI senses a leak.
- A whole room on one breaker: overload it, then fix it.
Materials for the whole unit
- AC voltage sensor, ZMPT101B
- Arduino Uno R3
- Bench power supply x 4
- Character LCD with I2C backpack
- Current sensor, ACS712 x 4
- DC jack and adapter
- Filament lamp x 3
- Full-size breadboard
- Half breadboard x 4
- LED
- Mains transformer, 230 V or 120 V to 12 V
- Multimeter x 2
- Pushbutton x 2
- Relay module
- Resistor x 9
- RGB LED x 4
- Signal generator
- Slide switch x 3
Every part is already on the simulator’s bench, so there is nothing to buy or hand out. The counts are the most any one lesson uses, if you build it on real breadboards too.
Where the power comes in
Two legs and a neutral, and the meter that counts every watt hour.
| Lesson | Time | What students do |
|---|---|---|
| The service: two legs and a neutralHow the power company feeds a North American house, on a one-tenth scale model: two legs and a neutral from a center-tapped transformer, 120 and 240 from the same wires, and why a lost neutral makes lights flare. | 40 min |
|
| The meter: watts and watt hoursWhat the meter on the side of a house counts: volts times amps is watts, watts times hours is energy, and the bill is in kilowatt hours. A real energy monitor sketch on a scaled AC sensor. | 50 min |
|
Materials
- AC voltage sensor, ZMPT101B
- Arduino Uno R3
- Character LCD with I2C backpack
- Current sensor, ACS712
- Filament lamp x 3
- Mains transformer, 230 V or 120 V to 12 V
- Multimeter x 2
- Resistor
- Signal generator
- Slide switch
Check for understanding
Each student finishes "The meter: watts and watt hours" on their own, without opening the hints. The simulator checks 6 of its 6 steps as they go.
Then ask each one to explain, in a sentence or two, the last thing it asked of them: "Who owns the meter".
The panel and its circuits
Breakers, branch circuits and the three wires every circuit runs.
| Lesson | Time | What students do |
|---|---|---|
| The panel and its branch circuitsA main panel splits the service into branch circuits, each behind its own breaker. A load monitor on four stand-in circuits shows breaker ratings, the 80 percent line for continuous loads, overloads and balancing the two legs. | 50 min |
|
| Hot, neutral and groundThree wires with three jobs: the hot brings the push, the neutral brings the current home, and the ground is there only for a fault. A 12 V lamp with a metal case shows what the ground wire saves you from. | 40 min |
|
Materials
- Arduino Uno R3
- Bench power supply x 4
- Current sensor, ACS712 x 4
- Filament lamp
- Full-size breadboard
- Half breadboard x 4
- LED
- Multimeter
- Resistor x 9
- RGB LED x 4
- Slide switch x 3
Check for understanding
Each student finishes "Hot, neutral and ground" on their own, without opening the hints. The simulator checks 5 of its 5 steps as they go.
Then ask each one to explain, in a sentence or two, the last thing it asked of them: "Bonded at one place".
Switching lights
Switch loops, three-ways and four-ways, with every flip checked.
| Lesson | Time | What students do |
|---|---|---|
| Switch loops and three-way switchesA switch goes in the hot, never the neutral. Then one light from two places: two SPDT switches joined by travelers, on a 12 V model, with every flip checked. | 35 min |
|
| Four-way switches: three places, one lightA long hall or a stair needs a light from three places: a four-way switch between the two three-ways swaps the travelers. Modeled as parity on an Uno with three slide switches. | 40 min |
|
Materials
- Arduino Uno R3
- Full-size breadboard
- Half breadboard
- LED
- Resistor
- Slide switch x 3
Check for understanding
Each student finishes "Four-way switches: three places, one light" on their own, without opening the hints. The simulator checks 5 of its 5 steps as they go.
Then ask each one to explain, in a sentence or two, the last thing it asked of them: "In the wall".
Receptacles and GFCI
What an outlet carries and how a GFCI senses a leak.
| Lesson | Time | What students do |
|---|---|---|
| Receptacles and GFCI protectionAn outlet's hot, neutral and ground, and the idea inside a GFCI: compare the current going out with the current coming back, and trip on the difference. A clearly labeled teaching model, not a real GFCI. | 55 min |
|
Materials
- Arduino Uno R3
- Current sensor, ACS712 x 2
- DC jack and adapter
- Filament lamp
- Half breadboard
- Pushbutton x 2
- Relay module
- Resistor
- Slide switch
Check for understanding
Each student finishes "Receptacles and GFCI protection" on their own, without opening the hints. The simulator checks 7 of its 7 steps as they go.
Then ask each one to explain, in a sentence or two, the last thing it asked of them: "Where GFCIs go".
Boss project
A whole room on one breaker: overload it, then fix it.
| Lesson | Time | What students do |
|---|---|---|
| Boss: wire a model roomOne room on one breaker: a ceiling light on a three-way pair, a desk lamp and a space heater on the outlets, and a meter on the main. Overload it, then fix the room so everything runs. | 50 min |
|
Materials
- Bench power supply
- Filament lamp x 2
- Multimeter
- Resistor
- Slide switch x 3
Check for understanding
Each student finishes "Boss: wire a model room" on their own, without opening the hints. The simulator checks 6 of its 6 steps as they go.
Then ask each one to explain, in a sentence or two, the last thing it asked of them: "Make it yours".
Teach this unit as a class
Start a class from this course and its 8 lessons are assigned in one go, in order. Students join with a six-character code or printed login cards, and each one’s work comes back to you.
The class tools are free for 30 days for one class of up to 20 students, with no card. The lessons themselves are free either way.