Read earthing and bonding connections
Identify exposed metalwork, protective conductors, the main earthing terminal and an earth electrode without confusing PE with neutral.
Educational reference only. Examples and calculator results are not approved installation designs, equipment selections or operating instructions.
Learning goal: Explain protective earthing and bonding roles, identify a common earthing terminal and recognize what a conceptual bonding view leaves out.
Explore the diagram
This is a bonding relationship diagram, not a complete power SLD or fault-loop model. It separates protective connections from normal load supply. Earthing symbols do not mean zero impedance, zero touch voltage or guaranteed safety; the earthing system and protective devices must be considered together.
Click or tap equipment to learn its purpose. Keyboard: Tab then Enter or Space. On small screens, scroll the drawing sideways or use the equipment selector.
- Double stroke: protective / earthing connection
Read it in order
- Identify the exposed metalwork E1 and E2, then trace their protective connections toward MET1. These are not normal load-supply conductors.
- Distinguish PE1 from the earthing conductor connecting MET1 to GE1. The common terminal is a connection point, not a circuit breaker or relay.
- Ask what is missing: the source earthing arrangement, a full fault-current loop and disconnection devices. Do not choose protection or infer touch-voltage safety from this view.
All equipment, explained
Read every explanation here without using the interactive controls.
E1 — Exposed equipment metalwork
A touchable conductive enclosure that is not normally live but could become live after an insulation fault.
How to read it here
Its protective connection is shown to the common terminal via PE1; the internal live conductors are not drawn.
What you cannot infer
Not all equipment has this protection arrangement. Do not infer an actual enclosure’s protection class from this sketch.
Supporting reference: Schneider Electric — Earthing connections and definitions.
PE1 — Protective conductor (PE)
Connects exposed metalwork to the protective earthing system and can carry fault current. It is not the neutral conductor.
How to read it here
The green double-stroke connection is protective, not the normal load-power path. PE1 is a label for this conceptual connection.
What you cannot infer
No conductor size, material, continuity test or permitted disconnection is specified here.
Supporting reference: Schneider Electric — Protective earthing conductor connections.
MET1 — Main earthing terminal
A common connection point for protective and bonding conductors and the means of earthing.
How to read it here
E1 and E2 have parallel connections to the common terminal, rather than one enclosure being a series link for the other.
What you cannot infer
This diagram does not specify where a source neutral is earthed or authorize a neutral-to-PE link.
Supporting reference: Schneider Electric — Earthing connections and definitions.
E2 — Second equipment enclosure
Another exposed conductive part with a protective connection to the common earthing system.
How to read it here
Trace its separate branch toward MET1. Removing E1 from the sketch does not remove E2’s shown connection.
What you cannot infer
Actual bonding continuity and protection cannot be verified by a diagram alone.
Supporting reference: Schneider Electric — Protective earthing conductor connections.
GE1 — Earth electrode
A conductor or group of conductors in electrical contact with the ground, connected here to MET1 by an earthing conductor.
How to read it here
The descending bars mark an earth connection. The earth electrode is not a device that simply absorbs or eliminates fault current.
What you cannot infer
The source and fault-current return path are omitted. Earth alone is not proof of automatic disconnection; TN, TT and IT arrangements differ.
Supporting reference: Schneider Electric — Earthing connections and definitions.
Check your understanding
Think through each question, then reveal its explanation. This is practice, not a competence assessment.
Is PE1 a neutral conductor for normal load current?
No. PE denotes a protective conductor. This lesson does not illustrate a combined PEN conductor or authorize joining neutral and PE.
Does GE1 by itself prove a fault will be cleared safely?
No. A complete fault-return path, earthing arrangement and suitable protective devices must be assessed; the electrode symbol alone proves none of these.
Textbook references
Suggested technical background for this topic. These books are further reading, not proof that every explanation was checked against every edition. See the full bibliography and review scope.
- Electric Power Distribution HandbookGrounding and safety fundamentals in distribution systems.
- Protective Relaying: Principles and ApplicationsSystem grounding, relay input sources and protection principles.