Position of the earth contact

Plugs and sockets with rated voltages above 50V must have an earth contact. To prevent incorrect insertion, a nose on the plug fits into a keyway in the socket, thus ensuring that the earth contact pin or tube is correctly positioned in accordance with the required electrical standard.

The earth contact positions for the various frequencies and voltages are assigned to a clock-face position, in accordance with table 104 taken from EN 60309-2:1999 (see table below).

The diameter of the earth contact pin is larger than that of the phase contact pins, which prevents incorrect insertion.

It must be impossible for the user to change the position of the earth contact or of any neutral contacts relative to the keyway of a socket or to the nose of a plug.

It also must be impossible to install a plug insert in the casing of a socket or connector.

Clock positions according to EN 60309-2:1998, Series I (Europe)
Position of ground contact sleeve with respect to major keyway for various voltages and frequencies. The colour codes correspond to the nominal voltage.

* Clock positions not normed and free for use for special applications.

Table 104 taken from EN 60309-2:1999.

*   Devices of series II are mainly used in the US and in Canada.
1   The position of the earth contact is given as a clock-face number.
2   Mainly for marine installations.
3   Only for reefer containers (ISO standard)
(-) Positions marked with a dash (-) are not standardised.

Examples: Front view of socket

400V = 6h	230V = 9h