Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

SSU

IEC

Shaver supply unit

A shaver supply unit contains a small isolating transformer so that the outlet is not referenced to earth. IEC-style plan symbols show the outlet half circle with two linked circles on the lead, the same pair of circles used for a transformer in diagrams, to show that the outlet is fed through isolation.

Drawing use

GA

Application

Installation & communications

Reference family

IEC

Form evidence

Socket outlet with isolating transformer. IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier.

A distinction that matters

A general outlet in a bathroom position is not isolated from earth; the shaver supply unit is.

Full referenceAdd to legend

SO

IEC

Socket outlet with protective earth contact

On an installation plan this mark places a socket outlet whose contact set includes a protective earth pin or earthing clip. The basic half-circle outlet form is completed by a straight bar across the top of the curve, which tells the reader that the outlet connects the protective conductor of the final circuit to the plug.

Drawing use

GA

Application

Installation & communications

Reference family

IEC

Form evidence

Socket outlet with protective contact. IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier.

A distinction that matters

A plain socket-outlet mark shows an outlet position only; the earth bar adds the protective contact. The protective earth terminal symbol itself is a schematic conductor mark, not an outlet.

Full referenceAdd to legend

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.