Circuit Walkthroughs
Twenty circuits, from one lamp to a full panel.
Each walkthrough lists the components, the wiring path, the build steps and the one thing that catches people out. Component names link to their anatomy page, so you can drop into the part and come straight back.
Beginner circuits
Start here if you are new to household wiring or electrical notation.
- 01Protected Lamp CircuitThe shortest complete circuit here: a supply, one protective device and a lamp, with nothing to switch it. Build this first — every other walkthrough is this path with something added.Beginner
- 02Single-Lamp Switched CircuitThe most fundamental circuit in household wiring. A switch in series controls one bulb. This is the exact wiring behind every ceiling light.Beginner
- 03Two-Bulb Parallel CircuitWire two bulbs in parallel so each receives full voltage independently. This is how all household lighting and sockets are wired — one bulb failing or being removed has no effect on the other.Beginner
- 08Doorbell CircuitBuild the classic doorbell: a Push Button (momentary switch) in series with a Bell/Buzzer. The bell sounds only while the button is held — exactly like a real doorbell.Beginner
- 09Timer-Controlled BellA bell or buzzer on a timed contact. The timer switch is an ordinary switch driven by a clock, which is why the bell sounds for a set period and then stops on its own.Beginner
Intermediate circuits
Combine switching, protection and timed or contactor-based control.
- 04Two-Way Switching (Staircase Circuit)Control one light from two separate locations — the classic staircase or hallway circuit. Switch the light on upstairs, switch it off downstairs, and vice versa.Intermediate
- 05RCD-Protected Socket CircuitAdd earth fault protection to a socket outlet using an RCD. This is mandatory in bathrooms, kitchens, and outdoor circuits in modern installations.Intermediate
- 06Timed Outdoor LightingAutomate an outdoor light to turn on and off at set times using a Timer Switch — no manual intervention required once programmed.Intermediate
- 07Dimmable Lighting CircuitAdd a Dimmer Switch to a lighting circuit for variable brightness control. Use this for living rooms, dining rooms, and any space where ambience matters.Intermediate
- 10RCBO-Protected SocketA socket outlet fed through an RCBO, with its protective earth run straight from the earth terminal and a lamp standing in for a plugged-in appliance. One device covers both overcurrent and earth-leakage protection for the whole circuit.Intermediate
- 11Contactor Motor StarterA motor branch switched by a contactor. The MCB protects the cable, the contactor does the switching, and it breaks live and neutral together so the motor is isolated when the coil drops out.Intermediate
Advanced circuits
Work through larger installations, special locations and three-phase equipment.
- 12Full Consumer Unit (3-Circuit Panel)Build a complete home breaker panel using a Distribution Board. Three independent circuits — lighting, sockets, and a motor — each protected by their own MCB.Advanced
- 13Three-Phase DOL Motor StarterHow an industrial motor is started: three live phases, each on its own Type-D breaker, into a three-pole contactor and out to the windings. Direct-on-line means the motor gets full voltage from the first turn.Advanced
- 14EV Charger Dedicated CircuitA 7.4 kW charge point on a circuit of its own: a rotary isolator that can be locked off, an RCBO covering both fault currents, and an earth run straight to the unit.Advanced
- 15Solar PV with Battery StorageA small DC system: a PV array and a battery share a DC bus through a combiner, feeding a 12 V load. DC has polarity rather than live and neutral, and both rails matter just as much.Advanced
- 16Underfloor Heating ZoneA dedicated heating circuit: Type-C breaker, a heating thermostat switching both poles, and the mat itself. Heating is a fixed load, so it never shares a circuit with anything else.Advanced
- 17Motion-Activated FloodlightA PIR sensor switching a halogen floodlight. Unlike a plain switch, an active sensor needs its own live and neutral supply before it can switch anything at all.Advanced
- 18Cooker & Induction Hob SupplyCookers are among the heaviest loads in a home. They get a dedicated circuit, a control unit beside the appliance, and conductors sized for the rating — with diversity applied, not assumed.Advanced
- 19Diesel Generator Backup SupplyA standby generator feeding emergency lighting and an alarm, earthed to its own rod. Backup generation is a small installation in its own right, with its own earth reference.Advanced
- 20AFDD-Protected Bedroom CircuitA bedroom final circuit on an AFDD-RCBO, feeding a socket and a light — the BS 7671 421.1.7 recommendation for sleeping accommodation, where a fire can start unnoticed.Advanced
Read one, then build it.
Every walkthrough that matches a guided circuit links straight into the editor with the parts already placed.