We Claim:
1. A gas insulated electric apparatus (1) comprising an enclosure (2), an electric high voltage appliance (3) arranged inside the enclosure (2) and a permeation barrier (5) arranged within the enclosure (2) and circumferentially surrounding the electric high voltage appliance (3), whereby

the enclosure (2) contains an insulation gas (4) comprising at least 70 % by volume of CO2 and comprising an elevated and pre-determined operating gas pressure level,

the permeation barrier (5) comprises a permeation layer (6) surrounded on at least one side by a flow promoter layer (7) and/or a surface activation and/or primer layer (8), and

the permeation layer (6) comprises ethylene vinyl alcohol, EVOH and/or aluminium oxide foil.

2. The gas insulated electric apparatus (1) of the previous claim, whereby the permeation layer (6), the flow promoter layer (7) and/or the surface activation and/or primer layer (8) are provided as a sheet and/or as a strip, preferably as preferably overlapping wrapped strips, preferably overlapping in axial and/or circumferential direction.

3. The gas insulated electric apparatus (1) of any of the previous claims, comprising the flow promoter layer (7), whereby the flow promoter layer (7) comprises a fleece and/or mesh.

4. The gas insulated electric apparatus (1) of any of the previous claims, whereby the permeation barrier (5) is arranged within the enclosure (2) adjacent to an inside of the enclosure (2) and/or closer to the inside than to the outside of the enclosure (2).

5. The gas insulated electric apparatus (1) of any of the previous claims, comprising a plurality of permeation barriers (5) arranged in particular distant to each other within the enclosure (2).
6. The gas insulated electric apparatus (1) according to any of the previous claims, wherein the electric high voltage appliance (3) is provided as a high voltage interrupter.

7. The gas insulated electric apparatus (1) according to any of the previous claims, wherein the electric apparatus (1) is provided as a gas insulated live tank circuit breaker, as a gas insulated dead tank circuit breaker, as a bushing or as a gas insulated switchgear.

8. The gas insulated electric apparatus (1) according to any of the previous claims, wherein the electric apparatus (1) is provided as an outdoor gas insulated electric apparatus.

9. Method for manufacturing a gas insulated electric apparatus (1) comprising an electric high voltage appliance (3), comprising the steps of:

Manufacturing an enclosure (2) for arranging the electric high voltage appliance (3) therein, and

Applying, during manufacturing, a permeation barrier (5) within the enclosure (2) circumferentially surrounding the electric high voltage appliance (3), whereby the permeation barrier (5) comprises a permeation layer (6) surrounded on at least one side by a flow promoter layer (7) and/or a surface activation and/or primer layer (8), and

the permeation layer (6) comprises ethylene vinyl alcohol, EVOH and/or aluminium oxide foil.

10. Method according to the previous method claim, whereby the enclosure (2) comprises an epoxy based composite isolator, the epoxy based composite isolator comprises wet wound fibres and/or the manufacturing comprises vacuum impregnating the epoxy based composite isolator.