A metal-encapsulated, gas-insulated switching installation is provided with at least one busbar system, the busbar system having an axis separation, and a circuit breaker, the circuit breaker being in the form of a pole and having a pole axis, the circuit breaker including at least one quenching chamber installed in a pole enclosure and at least one connection for the associated busbar system. The pole axis is arranged at a right angle to a surface of a foundation. The circuit breaker of the switching installation includes a modular circuit breaker pole. The modular circuit breaker pole includes an enclosure lower part having a first end and a second end, and at least one opening for connecting an isolator for a busbar system between the first end and the second end of the enclosure lower part, an enclosure upper part having a first end and a second end, at least one of the first end and the second end of the enclosure upper part being attachable to each of the first end and the second end of the enclosure lower part, and an enclosure cover attachable to at least one of the second end and the first end of the enclosure upper part. The enclosure lower part, the enclosure upper part, and the enclosure cover define at least part of a circuit breaker pole enclosure having a pole axis.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention is based on a metal-encapsulated, gas-insulated switching 
installation. 
2. Discussion of Background 
Single-phase, metal-encapsulated, gas-insulated switching installations 
having vertically positioned circuit breakers are known, which have a 
double busbar system. Such a switching installation is known, for example, 
from the specialist journal "E und M" [E and M], 102nd year, issue 7/8, 
page 305, FIG. 2. The pole axis of the circuit breakers is positioned 
vertically, and the circuit breakers are operated from below. The pole 
axes lie in a plane. The busbar systems have busbar axes which lie in 
planes which extend parallel to the foundation surface and vertically with 
respect to the plane in which the pole axes lie. A complex 
metal-encapsulated connecting piece leads from each circuit breaker pole 
to the associated busbars. These connecting pieces are of different length 
for each phase. A busbar isolator is provided between each of the busbars 
and that end of the respective connecting piece which faces the busbars. 
That end of the respective connecting piece which faces the busbars can be 
grounded by means of a grounding switch. The outlets and inlets all leave 
the circuit breaker at a specific height. The connecting pieces are 
likewise all connected to the circuit breaker in the same plane, which is 
parallel to the foundation surface. The pole enclosures of the circuit 
breaker are accordingly all constructed identically. 
Such a metal-encapsulated, gas-insulated switching installation requires a 
comparatively large amount of space, because of the predetermined 
geometry. The connecting pieces to the busbars increase the cost of the 
switching installation. 
SUMMARY OF TEE INVENTION 
Accordingly, one object of the invention, as it is characterized in the 
independent claims, is to provide a novel metal-encapsulated, 
gas-insulated switching installation which can be constructed using simple 
means such that it has a considerably smaller space requirement. 
The advantages which are achieved by the invention can be seen in the fact 
that the connecting enclosures which are required in the case of 
conventional gas-insulated switching installations and bridge the 
different separations between the circuit breaker poles and the busbars 
are no longer required. As a result of the absence of these connecting 
enclosures, denser packing of the apparatuses installed in the 
gas-insulated switching installation becomes possible. 
This metal-encapsulated, gas-insulated switching installation is provided 
with at least one busbar system which has an axis separation s, 
furthermore with a circuit breaker which, per pole, in each case has one 
pole axis, at least one quenching chamber installed in a pole enclosure 
and at least one connection, located on a connecting axis for the 
respectively associated busbar, and whose pole axes are arranged at right 
angles to a foundation and lie in a first plane. In addition, the 
gas-insulated switching installation in each case has an electrically 
conductive connecting part which extends along the connecting axis and 
connects the at least one connection of the respective pole to at least 
one of the busbar systems and, furthermore, in each case has one isolator 
which is arranged between the at least one busbar and the pole. The busbar 
axes of the at least one busbar system run parallel to the foundation 
surface and lie in at least one further plane. The first plane in which 
the pole axes lie is arranged parallel to the at least one further plane, 
and the connections for the busbars lie on a diagonal. 
It has been found to be particularly advantageous if two busbar systems are 
arranged respectively in a second plane and a third plane, and if the 
first plane, in which the pole axes lie, is arranged in the centre between 
the second plane and the third plane. 
A particularly economical solution results if each connection is connected 
to a connecting part which extends along connecting axes which run at 
right angles to these planes, and if all these connecting parts have the 
same physical length. 
In the case of this metal-encapsulated, gas-insulated switching 
installation, connections, which are arranged at different heights from 
pole to pole, are provided for the respectively associated busbar, and 
these differences are achieved solely by modifications in the construction 
of the poles without having to use separate and variable connecting parts. 
Each of the pole enclosures of a three-pole circuit breaker is constructed 
from in each case one enclosure lower part, which is fitted with the 
connections, at least one enclosure upper part and an enclosure cover, the 
enclosure cover being installed in each of the pole enclosures as an 
identical part, and the enclosure lower part furthermore being installed 
at the bottom in each of the pole enclosures as an identical part, but not 
in the same installed position. 
The invention, its development and the advantages which can be achieved 
thereby are explained in more detail in the following text, with reference 
to the drawing, which illustrates only one possible embodiment.

Only those elements which are required for immediate understanding of the 
invention are illustrated. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings, wherein like reference numerals designate 
identical or corresponding parts throughout the several views, FIG. 1 
shows a schematically illustrated side view of an outlet panel 1 of a 
single-phase, metal-encapsulated, gas-insulated switching installation, 
and FIG. 2 shows a plan view of this outlet panel 1. This outlet panel 1 
has a supporting frame 2 which is manufactured from a metal section. 
I-sections or tubular sections made of steel can be used, for example, as 
particularly suitable metal sections. As a rule, the tubular profiles have 
a round or a rectangular cross section. Angled sections 3, which are used 
for connecting the supporting frame 2 to a foundation 4, are fitted to the 
corners of the supporting frame 2. This connection can be constructed in a 
force-fitting manner, but it can also allow the supporting frame 2 to 
slide on a supporting rail which is incorporated in the foundation 4 and 
is not illustrated here. In the case of this type of metal-encapsulated 
and gas-insulated switching installation, the busbars 5 are arranged 
vertically one above the other on one side or on both sides of the 
vertically positioned poles of the circuit breaker 6. The outlet is 
provided with a current transformer 7, downstream of which an isolator 8 
is connected, which carries out the function of outlet isolator. A 
grounding switch is provided on each of the two sides of the isolator 8. A 
voltage converter 9 is provided downstream of the isolator 8. A cable 
connection 10 connects the outgoing high-voltage cable 11 to the 
gas-insulated switching installation. A panel which is provided for an 
inlet is constructed in a similar manner to the described outlet panel 1. 
The busbars 5 each have a busbar axis 12. The busbar axes 12 of each of the 
two busbar systems lie in a plane, vertically one above the other. The 
poles of the circuit breaker 6 each have a pole axis 13. The pole axes 13 
of the three circuit breaker poles lie in a plane which is positioned 
vertically with respect to the foundation 4. The planes in which the 
busbar systems lie and the plane in which the pole axes 13 lie are 
arranged parallel to one another in this outlet panel 1. That part of the 
outlet panel 1 which leads away from the respective circuit breaker pole, 
the current transformer 7, the isolator 8 and the enclosure onto which the 
cable connection 10 is flange connected extend along a longitudinal axis 
14. The longitudinal axis 14 is positioned vertically on the respective 
pole axis 13. That part of the outlet which leads away from the circuit 
breaker 6 can extend in the direction as illustrated in FIG. 1, but it can 
also extend in the opposite direction. The upper part of the pole 
enclosure, which is composed of the enclosure upper part and the enclosure 
cover, can be aligned in a corresponding manner during assembly. As a 
rule, a rotation through 180.degree. about the pole axis 13 is carried 
out, but it is also possible to turn the upper part of the pole enclosure 
off through an angle in the region of 180.degree.. Since the circuit 
breaker 6 is provided with a separate drive per pole, each of the poles 
can have differently aligned outlets. 
In the case of a feed panel which is of similar construction to the outlet 
panel 1 and in which the inlet extends along the respective longitudinal 
axis 14, for example as fas as bushings which are connected to an overhead 
line, this option to rotate the upper part of the pole enclosure has a 
particularly advantageous effect since, in this way, sufficient phase 
separations for the insertion of the overhead line can easily be 
implemented even in switching installations having confined spatial 
conditions. 
The connection from the respective circuit breaker pole to the busbars 
extends along a connecting axis 15. It can be seen from FIG. 1 that only 
one grounding switch 16 is provided per connection in the case of the 
outlet panel 1 which is equipped with a double busbar system. In the case 
of this gas-insulated switching installation, one of the two grounding 
switches which are normally required in this region is saved without any 
adverse effects on safety and without reducing the availability of the 
installation. In the case of a switching installation having a double 
busbar system, the grounding switch 16 can optionally be installed on 
either one side or the other side of the circuit breaker pole. 
If the switch panel is constructed as a coupler panel, then the space 
provided for the grounding switch on one side of the circuit breaker pole 
is adequate to close the pole enclosure with a cover in a pressuretight 
manner, and there is still enough space for the busbar so that, even in a 
coupler panel, the busbar axis 12 can be maintained unchanged in 
comparison with the feed and outlet panels. 
FIG. 3 shows a schematic illustration of the section 3--3 shown in FIG. 1. 
The pole axis 13 is positioned vertically on the plane of the section and 
passed through it at a central point 17. A cylindrically constructed 
enclosure lower part 18, which extends along the pole axis 13, is provided 
with two openings, which lie on the connecting axis 15 as the centre, are 
not shown, and are in each case flange-connected in a pressuretight manner 
to a compartment insulator 19, 20 which is of cylindrical construction and 
is in the form of a disc. The compartment insulator 19 has an electrical 
connection 21 which passes through it in the centre. The compartment 
insulator 20 has an electrical connection 22 which passes through it in 
the centre. An electrically conductive connecting piece 23, which is 
surrounded by a shield 24 designed in a dielectrically favorable manner, 
is screwed onto the electrical connection 22. The connecting piece 23 is 
firmly screwed to a contact ring 25 made of an electrically highly 
conductive metal. The connecting piece 23 and the contact ring 25 can also 
be constructed integrally. The contact ring 25 has a contact arrangement 
26, which is screwed to it, on the side opposite the connecting piece 23. 
The electrical connection 21 is connected to a contact support 27 which is 
fitted, for example, with spiral contacts. The contact arrangement 26 
encloses the contact support 27 and, with it, forms a detachable plug 
contact which is surrounded by a shield 28 which is designed in a 
dielectrically favorable manner. 
The centre point of the contact ring 25 coincides with the central point 
17. The cylindrically constructed inner surface of the contact ring 25 is 
provided with at least one groove, which is not illustrated and into which 
a plastic ring, which is not illustrated, is bonded. During installation 
of the quenching chamber, the plastic ring guides the electrically 
conductive exhaust enclosure of the same, which is fitted externally with 
elastic contact elements, for example with spiral contacts, which produce 
an electrical contact with the contact spring 25, and the elastic contact 
elements are thus prevented from being subjected to any asymmetrical 
mechanical stress. The inner opening of the contact ring 25 is completely 
closed by the exhaust enclosure, which is connected to the quenching 
chamber. The enclosure 29 of an isolator 30, which is constructed as an 
angled isolator, is flange-connected in a pressuretight manner on that 
side of the compartment insulator 19 which is opposite the contact support 
27. 
The enclosure 29, which is illustrated in simplified form, on the isolator 
30 has a wall made of metal. As a rule, the enclosure 29 is cast from an 
aluminum alloy in a pressuretight manner. Apart from the opening which is 
closed by the compartment insulator 19, the enclosure 29 has five further 
openings, which are not illustrated and are provided with flanges 31 to 
35. In addition, the enclosure 29 has a longitudinal axis which coincides 
with the connecting axis 15. The opening which is provided with the flange 
31 is provided during assembly of the isolator with a metallic cover 36, 
which has a flange 37 which is screwed in a gas-tight manner to the flange 
31. A further flange 38 is fitted to the cover 36, opposite the flange 37. 
The flange 38 is used for the attachment of a pressure-resistant bushing 
for an insulating material rod 39 which can be moved, during a switching 
process of the isolator 30, in the direction of an operating axis which 
coincides with the connecting axis 15. Driven by an isolator drive 40 
which is likewise connected to the flange 38, the insulating material rod 
39 moves the moving contact arrangement 41, which is illustrated in highly 
schematic form, of the isolator 30. The moving contact arrangement 41 is 
surrounded by a dielectrically acting shield 42, through which the 
insulating material rod 39 passes. 
A busbar enclosure, which is not illustrated, is flange-connected to the 
flange 32. A compartment insulator 43, through which an electrical 
connection 44 passes, is flange-connected to the flange 33. A conductor 
piece 45 is screwed onto the electrical connection 44 and is sheathed on 
the insulator side by a dielectrically acting shield 46. The conductor 
piece 45 extends along the busbar axis 12, which runs vertically with 
respect to the connecting axis 15. The conductor piece 45 is electrically 
conductively connected to a first stationary contact support 47 of the 
isolator 30. A sliding contact 48 is incorporated in the contact support 
47 and is provided in order to transfer current from the moving contact 
arrangement 41 of the isolator 30 to the contact support 47. The sliding 
contact 48 is arranged concentrically with respect to the connecting axis 
15 and is provided with contact fingers, with contact laminates, or with 
spiral contacts. The contact support 47 is arranged concentrically with 
respect to the connecting axis 15. The contact support 47 is at the same 
time constructed as part of the busbar active parts. Fitted on the side of 
the contact support 47 opposite the conductor piece 45 is a further 
conductor piece 49, which extends along the busbar axis 12 through the 
opening which is provided with the flange 32. The electrical connection 21 
is electrically conductively connected to a second stationary contact 
support 50 of the isolator 30. That end of the contact support 50 which is 
on the insulator side is covered by a dielectrically acting shield 51. 
That end of the contact support 50 which faces the contact support 47 is 
provided with a mating contact 52, which is arranged concentrically with 
respect to the connecting axis 15, for the moving contact arrangement 41 
of the isolator 30. The contact supports 47 and 50 are formed to be 
dielectrically favorable, any edges being designed to be chamfered. The 
electrical connections 44 and 21 are at high-voltage potential in 
operation and are insulated from the metal encapsulation of the 
gas-insulated switching installation. 
In addition, a mating contact 53 is incorporated in the contact support 50, 
which mating contact 53 is constructed in the form of a tulip, is arranged 
concentrically with respect to an installation axis 54 and holds the 
contact pin 55 of the grounding switch 16 when said grounding switch 16 is 
closed. The installation axis 54 is positioned vertically on the 
connecting axis. When the isolator 30 is open, there is a separation 56 
between the contact support 47 and the mating contact 52. This separation 
56 corresponds to the isolating path of the isolator 30, which, in 
operation, withstands all the voltage loads which occur at this point as a 
result of operation. 
During connection of the isolator 30, the moving contact arrangement 41 is 
moved along the connecting axis 15, towards the mating contact 52, by the 
insulating material rod 39, which is operated by the isolator drive 40. 
Pre-arcing, which may be caused by residual charges and/or by a voltage of 
the operating frequency which is present between the contact support 47 
and the mating contact 52, between the moving contact arrangement 41 and 
the mating contact 52 is coped with without any problems by the isolator 
30. The geometrical arrangement of the contact support 47 and the mating 
contact 52 can prevent any expansion of the pre-arcing arc towards the 
wall of the enclosure 29. The isolator drive 40 is designed such that it 
reliably moves the moving contact arrangement 41 into the intended 
connecting position in every possible operational case, thus ensuring that 
current is carried correctly via the rated current contacts which are 
provided for this purpose, but are not described in more detail. The 
opening of the isolator 30 likewise always takes place correctly. 
In this case, the grounding switch 16 is installed in the opening which is 
provided with the flange 34. As an alternative, however, it could also be 
installed in the opening which is provided with the flange 35. For 
example, detectors for monitoring the gas-insulated switching installation 
or, as shown in FIG. 3, a bursting disk 57, which makes it possible for 
pressure to escape from the enclosure 29 in the vent of a defect, can be 
flange-connected in a pressuretight manner to the flange 35. The two 
flanges 34 and 35 have a common installation axis 54. 
The enclosure 58, which is flange-connected on the other side of the 
enclosure lower part 18, corresponds with the enclosure 29 in terms of 
virtually all the built-in parts, just being arranged in the form of a 
mirror image with respect thereto, and no grounding switch is installed. 
The opening which is provided with a flange 59 and into which a grounding 
switch extending along an installation axis 60 could be installed is 
closed in a pressuretight manner by means of a cover 61. The mating 
contact of the grounding switch has also, likewise, not been installed. A 
contact support 62, which is fitted with a mating contact 63 of the 
isolator arranged on the right, is electrically conductively connected to 
the electrical connection 22 on the side facing away from the connecting 
piece 23. There is no need to instal a second grounding switch here, since 
the mating contact 63 and the contact support 62 are always, thanks to the 
electrically conductive contact ring 25, at the same potential as the 
contact support 50 and the mating contact 52, so that it is completely 
sufficient for these active parts to be reliably grounded, if required, 
jointly with the aid of the single grounding switch 16. 
The isolator can be installed in any desired installation position which is 
specified by the installation concept of the metal-encapsulated, 
gas-insulated switching installation. The grounding switch 16 can likewise 
be operated independently of position, so that it does not produce any 
installation limitations either. The grounding switch 16 can be 
constructed both as a work-in-progress grounding switch and as a 
quick-reaction grounding switch. The assembly formed by the isolator 30 
with the upstream grounding switch 16 is of very compact design and 
occupies a particularly small amount of space in the direction of the 
connecting axis 15, so that the switch panel can be designed with 
particularly small dimensions. 
The open isolating path of the isolator is insulated in a very highly 
reliable manner by means of SF.sub.6. The isolator has an optimum rated 
current carrying capacity in the closed state, a very high short-circuit 
carrying capacity, and surge-current resistance, Furthermore, it has a 
reliable switching capability with respect to small capacitive currents 
and, in addition, it copes with switching over in the case of an 
interruption-free busbar change. 
The isolator 30 has separate contact systems for carrying the continuous 
current and for the actual switching process. The continuous-current 
contacts are designed to be simple and reliable, and have a minimal number 
of individual parts. The contact movement is carried out by means of an 
electrically driven isolator drive which is arranged outside the isolator 
enclosure which is filled with SF.sub.6 gas, but the isolator can also be 
driven manually. Such a configuration simplifies the maintainance tasks in 
a very advantageous manner. The isolator is provided with a mechanically 
coupled position indicator and, furthermore, a sight glass can be provided 
for an endoscope for inspecting the position of the contacts. 
FIG. 4 shows a highly simplified schematic illustration of the section 
4--4, shown in FIG. 2, through a first pole of the circuit breaker 6. This 
pole has a metallic pole enclosure which is filled with insulating gas and 
is composed of a plurality of components which are connected to each other 
in a pressuretight manner. The pole enclosure has an enclosure lower part 
18, which is closed at the bottom by a cover flange 64, is of identical 
construction for all three poles of a three-pole circuit breaker 6, but is 
used in a different installed position. One contact-making assembly 65 is 
in each case installed in the enclosure lower part 18. This contact-making 
assembly 65 in each case comprises those parts described in conjunction 
with FIG. 3, such as the connecting piece 23 with the shield 24, the 
contact ring 25, the contact arrangement 26 and the contact support 27 
with the shield 28. The contact-making assembly 65 is on the one hand 
connected in a plug-in manner to the electrical connection 21 of the 
compartment insulator 19 and, on the other hand, is firmly connected to 
the electrical connection 22 of the compartment insulator 20. The circuit 
breaker pole has a quenching chamber 66 which has a cylindrically 
constructed exhaust enclosure 67, which is made of metal, is arranged 
concentrically with respect to the pole axis 13, is moved into the 
contact-making assembly 65 and is electrically conductively connected to 
said contact-making assembly 65 via sliding contacts such as spiral 
contacts, for example. The exhaust enclosure 67 transfers the potential of 
the contact-making assembly 65 to the lower part of the quenching chamber 
66 and, at the same time, carries the operating current when the circuit 
breaker pole is closed. 
Fitted on the enclosure lower part 18 is an enclosure upper part 68, which 
has an opening which is closed in a pressuretight manner by a compartment 
insulator 69 and is not shown. The compartment insulator 69 has an 
electrical connection 70 which passes through it, on the one hand is 
electrically conductively connected to the active parts of the outlet 
which are not illustrated and extend in the direction of the longitudinal 
axis 14 and, on the other hand, is connected via a blade contact 71 to the 
upper part 72 of the quenching chamber 66. The upper part 72 and the lower 
part of the quenching chamber 66 are connecting by a quenching chamber 
insulator 73 to form a unit. When the circuit breaker pole is 
disconnected, the quenching chamber insulator 73 insulates the upper part 
72 from the lower part. The quenching chamber 66 is connected by means of 
a holding insulator 74 to an enclosure cover 75, and is held in the centre 
of the pole enclosure by this enclosure cover 75. The enclosure cover 75 
is connected to the enclosure upper part 68 and closes the pole enclosure 
at the top. The enclosure cover 75 is provided with a bursting disk 75 
which, in an emergency, allows any overpressure occurring in the pole 
enclosure to escape to the environment. A drive 77 for the circuit breaker 
pole is flange-connected to the enclosure cover 75. The drive 77 does not 
sit on the pole axis 13 but is arranged alongside the pole enclosure, to 
be precise on that side of the pole enclosure which is opposite the outlet 
for the cable connection 10. The physical height of the circuit breaker 
pole is not increased, or is increased only insignificantly, by the drive 
77. The drive 77 acts via schematically indicated force conversion on an 
insulating operating rod 78 which moves the moving contact parts of the 
quenching chamber 66 along the pole axis 13. During assembly, the 
quenching chamber 66, which is attached to the enclosure cover 75, is 
inserted from above into the pole enclosure such that the exhaust 
enclosure 67 makes correct contact with the contact-making assembly 65, 
and such that the blade contact 71 likewise electrically connects the 
active parts of the outlet reliably to the upper part 72 of the quenching 
chamber 66. 
FIG. 5 shows a schematic illustration of the section 5--5 shown in FIG. 2 
through a second circuit breaker pole. This circuit breaker pole likewise 
has a metallic pole enclosure which is filled with insulating gas and is 
composed of a plurality of components which are connected to one another 
in a pressuretight manner. In the case of this pole, the longitudinal axis 
14 of the outlet is at the same level as in the case of the pole which has 
already been described. This pole enclosure has an enclosure lower part 18 
which is closed at the bottom by a cover flange 64 and is of identical 
construction for all three poles of the three-pole circuit breaker 6. In 
this case, it is installed in the same installation position as in the 
pole according to FIG. 4. The same contact-making assembly 65 is installed 
here in the enclosure lower part 18. The contact-making assembly 65 
produces the electrically conductive connection to an exhaust enclosure 
79. The enclosure lower part 18 is connected to an enclosure upper part 
80. The enclosure upper part 80 is designed to be shorter than the 
corresponding enclosure upper part 68 in FIG. 4, and the exhaust enclosure 
79 is designed to be shorter than the corresponding exhaust enclosure 67 
in FIG. 4, in each case by the same amount s. The amount s corresponds to 
the vertical axis separation between the busbars 5. The other components 
of the two switch poles of the circuit breaker 6 are of identical design. 
The shortening of the said components by the amount s results in the 
circuit breaker pole according to FIG. 5 likewise being shorter by this 
amount s, and the busbar connection of this pole, which extends along a 
connecting axis 81, being offset upwards by the amount s with respect to 
the connecting axis 15. 
FIG. 6 shows a schematic illustration of the section 6--6 shown in FIG. 2 
through a third pole of the circuit breaker 6. This circuit breaker pole 
has a metallic pole enclosure which is filled with insulating gas and is 
composed of a plurality of components which are connected to one another 
in a pressuretight manner. In the case of this pole, the longitudinal axis 
14 of the outlet is at the same level as in the case of the two poles 
already described. The pole enclosure has an enclosure lower part 18 which 
is closed at the bottom by a cover flange 64, is of precisely identical 
construction in the case of all three poles of the three-pole circuit 
breaker 6, but, in the case of this pole, is used rotated through 
180.degree. with respect to the installed position in the other two 
circuit breaker poles. A contact-making assembly 65 is in each case 
installed in the enclosure lower part 18. This pole is also shorter than 
the pole according to FIG. 4 by the amount s. 
The rotation of the enclosure lower part 18 through an angle of 180.degree. 
about an axis which runs parallel to the connecting axis 82 results in the 
busbar connection of this pole, which extends along a connecting axis 82, 
being offset upwards by twice the amount s with respect to the connecting 
axis 15, and likewise being offset upwards by this amount s with respect 
to the connecting axis 81. The connecting axis 82 is at a distance, which 
corresponds to the amount s, from the longitudinal axis 14, which is at 
the same level for all three circuit breaker poles. 
As can be seen from FIG. 1, the pole according to FIG. 4 is mounted on the 
supporting frame 2. As seen in FIG. 7, the other two poles, which are both 
shorter by the amount s, are preferably mounted on a platform 101 which is 
connected to the supporting frame 2 and is so high that the said dimension 
difference is compensated for. The platform is welded together from iron 
sections, is highly cost-effective, and can be produced at little cost. 
Apart from the platform, the enclosure upper part 68 extended by the 
amount s and the exhaust enclosure 67 likewise extended by the amount s, 
no further modified components are necessary in order to render 
superfluous connecting pieces which are complicated and of different 
length and are always used in the case of a conventionally constructed 
metal-encapsulated, gas-insulated switching installation, between the 
circuit breaker poles and the busbars assigned to them. 
In the case of the metal-encapsulated, gas-insulated switching installation 
according to the invention, the pole axes 13 are arranged in a plane. The 
pole axes 13 run vertically with respect to the foundation 4. The busbar 
axes 12 of a busbar system are likewise arranged in a plane vertically 
with respect to the foundation 4, but the busbar axes 12 run parallel to 
the surface of the foundation 4. If a gas-insulated switching installation 
having only one busbar system is produced, then this busbar system can 
optionally be arranged on one side or the other side of the plane of the 
pole axes 13 of the circuit breaker 6. For special applications, it is 
also possible to guide only one of the busbars of the system on the 
opposite side of the plane of the pole axes 13. If the gas-insulated 
switching installation is equipped with a double busbar system, then the 
busbar systems are, as a rule, arranged on both sides of the plane of the 
pole axes 13 of the circuit breaker 6, and with the same separation. As a 
result of this assignment of the busbars 5 in planes which are parallel to 
the pole axes 13 of the circuit breaker 6, a particularly space-saving 
arrangement of the busbar connections is possible, and they can be 
arranged on a diagonal. 
A particularly compact arrangement of the gas-insulated switching 
installation results when the separation between adjacent busbar axes 12, 
which corresponds to the amount s, is selected to be of equal size to the 
separation between adjacent pole axes 13. The connecting line between the 
connecting axes 15, 81 and 82 is then at an angle of 45.degree. with 
respect to the direction of the busbar axes 12. This arrangement of the 
connections results in increased flexibility in the design of 
metal-encapsulated, gas-insulated switching installations, and, in 
addition, an advantageous reduction in the number of components required 
for these gas-insulated switching installations. 
The described changes to the physical length of the pole enclosure of the 
pole according to FIG. 4 can also be achieved in a different manner. 
Instead of the extended enclosure upper part 68, a shorter enclosure upper 
part 80 can be installed, for example, as is used in the other two poles, 
it then being necessary only to extend the enclosure lower part 104 (FIG. 
9) in this pole to a corresponding extent upwards or to insert a 
correspondingly dimensioned intermediate ring 103 (FIG. 8) between the 
shorter enclosure upper part 80 and the enclosure lower part 18. As seen 
with reference to FIGS. 4-9, the circuit breaker 6 preferably includes an 
enclosure lower part 18 or 104, the enclosure lower part having a first 
end 18' or 104' and a second end 18" or 104" and at least one opening for 
connecting an isolator for a busbar system between the first end and the 
second end of the enclosure lower part. The circuit breaker 6 also 
includes an enclosure upper part 68 or 80 having a first end 68' or 80' 
and a second end 68" or 80", at least one of the first end and the second 
end of the enclosure upper part being attachable to either of the first 
end 18' or 104' and the second end 18" or 104" of the enclosure lower part 
18 or 104. The circuit breaker 6 also includes an enclosure cover 75 
attachable to either of the second end 68" or 80" and the first end 68' or 
80' of the enclosure upper part 68 or 80. The enclosure lower part 18 or 
104, the enclosure upper part 68 or 80, and the enclosure cover 75 define 
at least part of a circuit breaker pole enclosure having a pole axis, and 
a quenching chamber 66 is disposed inside of the pole enclosure and is 
electrically connectable to an isolator through the opening in the 
enclosure lower part. If desired or necessary, the intermediate ring 103 
may be disposed between the enclosure lower part and the enclosure upper 
part to extend a length of the circuit breaker. 
Obviously, numerous modifications and variations of the present invention 
are possible in the light of the above teachings. It is therefore to be 
understood that within the scope of the appended claims, the invention may 
be practiced otherwise than as specifically described herein.