2 min read
Earth and the Plug
A three-pin plug connects live, neutral, and earth conductors with IEC colours brown, blue, and green/yellow respectively.
Choose Your Level
Earth and the Plug
Recommended for Class 10
Earth and the Plug
A three-pin plug is designed to connect an appliance safely to the mains supply.
The three conductors are:
Live
Neutral
Earth
Live Wire
The live conductor carries the alternating supply potential relative to neutral/earth.
It is the conductor that presents the main electric-shock hazard under normal wiring conditions.
Neutral Wire
Neutral provides the normal return path for current in the supply circuit and is maintained close to earth potential in the distribution system.
It should still be treated as part of the electrical system rather than assumed completely harmless.
Earth Wire
The earth conductor is a protective conductor.
It is connected to exposed conductive parts of appliances that require earthing.
Under normal operation, it should not carry the appliance's load current.
Fault Condition
If a live conductor touches a correctly earthed metal case, the earth conductor provides a low-resistance path.
A large fault current can then cause the protective device to disconnect the supply.
Cable Colours
Under the widely used IEC colour convention:
Live → Brown
Neutral → Blue
Earth → Green/Yellow
Earth and the Plug — Advanced
Common Mistakes
Common Mistakes
- Mistake
Mistake: Earth is the normal return conductor. Correction: Earth is not the normal return conductor.
- Mistake
Mistake: Neutral and earth have the same function. Correction: Neutral and earth have different safety functions.
Revision Zone
60-Second Revision
Quick cues from this topic — use them for last-minute revision.
Live → supply.
Neutral → normal return.
Earth → safety.
- Definition
Did you understand this topic?
Your answer is saved with your learning record. It does not mark the topic as mastered.
Ready to test yourself?
You've completed the learning section.
Practice
PQ
Q1. Name three conductors.
PQ
Q2. State live function.
PQ
Q3. State neutral function.
PQ
Q4. State earth function.
PQ
Q5. State IEC colours.
Exam Practice
EQ
Q1. Explain construction/function of three-pin plug.
EQ
Q2. Compare live, neutral and earth.
EQ
Q3. Explain earthing during a fault.
EQ
Q4. State wire colours.
EQ
Q5. Explain why earth normally carries no load current.
School-standard facts for Matric and Intermediate. Original explanations — not copied from textbooks.