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A circle enclosing a three-bar earth glyph — IEC 60417-5019, marking the protective earth (ground) terminal on Class I equipment.
Also known as: Protective earth symbol, Ground symbol, Earth terminal symbol, IEC 60417-5019, PE symbol
Identifies the protective earth terminal: the connection that carries fault current safely to earth on Class I equipment. Its presence signals a fundamentally different shock-protection strategy from the Class II double-square symbol.
Identifies the protective earth terminal on Class I equipment — the terminal that must be connected to the installation's earth so that a fault cannot leave exposed metal live.
Contexts: Electrical equipment
Is one of three earth marks that are not interchangeable. Protective earth — the three-bar earth inside a circle — is the safety conductor that must be connected for the equipment to be safe. A plain three-bar earth without the circle is a functional earth, present for performance rather than safety, and the hatched wedge is a chassis or frame connection which may not be earthed at all.
Contexts: Technical drawing, Electrical equipment
Related forms that are not treated as separate canonical symbols — see our variant rules.
Functional earth
The three descending bars without an enclosing circle. A reference connection for noise or measurement, not a safety earth.
Chassis or frame connection
A short horizontal bar with three hatched strokes descending from it. Marks a connection to the metalwork, which is not the same claim as a connection to earth.
A circle containing a short vertical stem that meets three horizontal bars of decreasing length, the longest at the top — the conventional earthing glyph.
Opposite protection strategies: this marks the earth terminal that must be connected, while the double square means the appliance is insulated well enough not to need one.