LuduminaEL-07 · EL-U3 · Planned
AC, mains and electrical safety
Learning objectives
Distinguish AC/DC; explain live, neutral, earth and hazard protections in a supplied diagram.
8463 §§4.2.3.1–4.2.3.2 / 8464 §§6.2.3.1–6.2.3.2
DfE single-science pp.39–41 / Combined pp.33–34. Evidence checked 30 September–1 October 2026. Skills: WS1.5,3.6,4.1; MS4a.
Needs firstEL-06
Explanation
AC repeatedly reverses polarity; DC maintains one direction. Mains live conductors are dangerous relative to earth. In an earthed metal appliance, a live-to-case fault can drive a large fault current that operates protection. Diagram knowledge is not permission to handle mains.
Concepts, equations and units: UK mains about 230 V, 50 Hz AC; brown live, blue neutral, green/yellow earth; earth/neutral about 0 V; fuse and earthing.
Prediction, demonstration and game exercise
Predict, observe, explain
Use labelled diagrams and AC traces; show a live conductor can remain dangerous with a switch off.
Planned learner game exercise
Audit simulated appliances for insulation, correct wiring and earth connection; explain fault-current/fuse sequence.
Independent practice
Compare AC/DC traces and write three causal safety explanations.
Original practice example · Shared
Identify live, neutral and earth by the standard UK wire colours.
Show working and model answer
Working / reasoning
Live brown; neutral blue; earth green/yellow.
Answer
Brown live, blue neutral, green/yellow earth.
Exit check and success criteria
Three wires identified and both electric-shock and live-to-earth fault paths accurately explained.
During practice, compare the prediction with evidence and give an error-specific prompt. The exit item uses a fresh context or fresh values, answered independently.
Misconceptions, practical links and mastery
Check these misconceptions
Earth normally carries operating current; neutral can always be touched; a switched-off appliance is necessarily safe.
Practical preparation
Diagram-only mains activity; hands-on circuits use approved low voltage, AT7.
Virtual preparation and revision only. Required hands-on activities and school records remain separate.
Proposed mastery
0: not yet evidenced. 1: supported. 2: independent exit criteria met. 3: successful changed-context transfer. Advance at 2; revisit with fresh retrieval. These are not GCSE grades.