01
Protected Lamp Circuit
The 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.
Components Needed
Text Wiring Path
Live → MCB → Bulb → Neutral
Schematic
Steps
- 1Place a Live (L) terminal and a Neutral (N) terminal on the canvas.
- 2Place an MCB to the right of the Live terminal.
- 3Place a Bulb (E27) to the right of the MCB.
- 4Wire: Live → MCB → Bulb → Neutral.
- 5Press Run, then select the bulb and read its voltage and current in the Inspector.
- 6Toggle the MCB off and run again — the lamp goes dark because the live feed is gone, not because the neutral moved.
Key insight
A lamp needs both rails: a live feed and a neutral return. The MCB sits in the live conductor only, so opening it removes the feed while the neutral path stays connected back to the supply.
⚠ Safety practice
These walkthroughs teach wiring logic in a simulator. Real installation work must be isolated, tested dead, and carried out by a competent person — in the UK, notified under Part P or done by a registered electrician.
Terms used here
Defined in the glossary — each one opens at its own entry.
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Build this circuit in the browser, inject a fault, and watch the protection respond.