12
© Siemens AG • 07/2003
1
Support
2
Lower insulating socket
3
Base plate
4
upper insulating socket
5
Arrester
Fig. 12
Basic plate for isolated installation, 4-hole mounting 310 × 310 mm² 4× M20
suspended installation
The top and bottom plates may have to be exchanged together with their associated bolts and insulat-
ing parts to make it into a hanging version [Fig. 1], [Fig. 17]. In other respects, the arrester must be
installed at site in accordance with local conditions.
Grounding
The protective effect of surge arresters will be negatively affected with increasing length of the ground
wire, since a voltage drop occurs along the ground wire during a surge event. Thus, the ground wire
should connect the ground terminal of the arrester to the substation grounding system using the short-
est and most direct path. The length of the ground wire, if possible, should not exceed 1 m for medium
voltage surge arresters and 3 m for high voltage surge arresters. Even if the arrester is monitored by
devices connected in series with the ground wire, e.g. by control spark gap 3EX6 040 or surge counter
3EX5 030/050, the ground wire should be as short as possible and loops should be avoided. If moni-
toring devices are to be installed at a larger distance from the arrester, it is recommended to use de-
vices with separate sensors and display units, such as the surge monitor with sensor unit 3EX5 060
and display unit 3EX5 062. If monitoring devices are connected to the ground wire, the conductor be-
tween the earth terminal of the monitoring device and the grounding system of the substation must
protected against contact.
For installation of ground wire and monitoring devices the requirements of the corresponding national
or international standards are to be applied.
Standing or suspended installation:
Bolt the ground wire to one of the four M10 base flanges in accordance with [13a. Fig. 17].
Isolated installation
Bolt the ground wire to the M12 ground bolt in accordance with [14, Fig. 17].
Terminal
Attention!
High-voltage connections with tube conductors should be flexible in
order to prevent exertion of any inadmissible mechanical forces on
the surge arrester.
Pay attention to the electro-chemical compatibility of the materials utilised.
Terminal with cable eye
The terminal must be mounted with a cable eye according to [Fig. 13].
