Peripheral Circuitry; Upgrading/Servicing - GE MiCOM P747 Agile Technical Manual

Chapter 2 - Safety Information
4.8

PERIPHERAL CIRCUITRY

Warning:
Do not open the secondary circuit of a live CT since the high voltage produced
may be lethal to personnel and could damage insulation. Short the secondary of
the line CT before opening any connections to it.
Note:
For most Alstom equipment with ring-terminal connections, the threaded terminal block for current transformer
termination is automatically shorted when the module is removed. Therefore external shorting of the CTs may not be
required. Check the equipment documentation first to see if this applies.
Caution:
Where external components such as resistors or voltage dependent resistors
(VDRs) are used, these may present a risk of electric shock or burns if touched.
Warning:
Take extreme care when using external test blocks and test plugs such as the
MMLG, MMLB and MiCOM ALSTOM P990, as hazardous voltages may be
exposed. Ensure that CT shorting links are in place before removing MMLB test
plugs, to avoid potentially lethal voltages.
4.9

UPGRADING/SERVICING

Warning:
Do not insert or withdraw modules, PCBs or expansion boards from the
equipment while energised, as this may result in damage to the equipment.
Hazardous live voltages would also be exposed, endangering personnel.
Caution:
Internal modules and assemblies can be heavy. Take care when inserting or
removing modules into or out of the IED.
20
MiCOM P747
P747-TM-EN-1
P747-TM-EN-1.1