86
6 Maintenance
The following safety regulations provide an overview of the dangers existing and their sources, and describe the
possible consequences if the rules specified are not complied with. They are expressed more exactly in the
operating instructions.
Hazardous voltage - Electric shock and burning as a result of arcing are possible if live parts are
approached.
Before maintenance is to be done, a responsible person from the power supply utility must, before work starts:
- Switch off and isolate
- Prevent
unintentional
switch-on
- Test that equipment is dead
- Ground and short-circuit the equipment
- Cover or fence off nearby live parts
It must be confirmed that these safety measures have been taken.
The closing and opening springs may be charged. If the control and motor power supply are not switched
off, the closing spring will be automatically recharged after a closing operation. The spring state indicator
shows only the position of the closing spring - unintentional switching operations can lead to severe
personal injury.
Before beginning maintenance work, relax the opening and closing springs as follows:
- Disconnect motor power supply,
- open the circuit-breaker, if the circuit-breaker is in the CLOSED position.
- close the circuit-breaker and
- re-open the circuit-breaker.
- disconnect the control voltage.
The pole columns are under pressure (see section
3.1.6
Arc Quenching Medium SF
6
)
-
Damage to the
porcelain parts can result in severe personal injury.
- Before opening interrupter units, ensure pressure relief by means of the facility provided.
- After relieving the pressure, gradually and uniformly undo the screw joints.
- Do not allow any tools or hoisting gear to knock against the porcelain parts.
- Do not lean any ladders against the pole columns;use step ladders.
SF
6
is heavier than air and can displace the air required for breathing - Danger of suffocation!
