Alstom MiCOM P846, Technical Manual

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Safety Section P846/EN SS/H11
(SS) - 5
Watchdog (self-monitoring) contacts are provided in numerical relays to indicate
the health of the device. Alstom Grid strongly recommends that these contacts
are hardwired into the substation's automation system, for alarm purposes.
To ensure that wires are correctly terminated the correct crimp terminal and tool
for the wire size should be used.
The equipment must be connected in accordance with the appropriate connection
diagram.
Protection Class I Equipment
- Before energizing the equipment it must be earthed using the protective
conductor terminal, if provided, or the appropriate termination of the
supply plug in the case of plug connected equipment.
- The protective conductor (earth) connection must not be removed since
the protection against electric shock provided by the equipment would be
lost.
- When the protective (earth) conductor terminal (PCT) is also used to
terminate cable screens, etc., it is essential that the integrity of the
protective (earth) conductor is checked after the addition or removal of
such functional earth connections. For M4 stud PCTs the integrity of the
protective (earth) connections should be ensured by use of a locknut or
similar.
The recommended minimum protective conductor (earth) wire size is 2.5 mm²
(3.3 mm² for North America) unless otherwise stated in the technical data section
of the equipment documentation, or otherwise required by local or country wiring
regulations.
The protective conductor (earth) connection must be low-inductance and as short
as possible.
All connections to the equipment must have a defined potential. Connections that
are pre-wired, but not used, should preferably be grounded when binary inputs
and output relays are isolated. When binary inputs and output relays are
connected to common potential, the pre-wired but unused connections should be
connected to the common potential of the grouped connections.
Before energizing the equipment, the following should be checked:
- Voltage rating/polarity (rating label/equipment documentation);
- CT circuit rating (rating label) and integrity of connections;
- Protective fuse rating;
- Integrity of the protective conductor (earth) connection (where
applicable);
- Voltage and current rating of external wiring, applicable to the application.
Accidental touching of exposed terminals
If working in an area of restricted space, such as a cubicle, where there is a risk of
electric shock due to accidental touching of terminals which do not comply with
IP20 rating, then a suitable protective barrier should be provided.
Equipment use
If the equipment is used in a manner not specified by the manufacturer, the
protection provided by the equipment may be impaired.
Removal of the equipment front panel/cover
Removal of the equipment front panel/cover may expose hazardous live parts,
which must not be touched until the electrical power is removed.
SS