Areva MiCOM P341, Operation Manual

Page: 9 / 282

HANDLING OF ELECTRONIC EQUIPMENT
A person’s normal movements can easily generate electrostatic potentials of several
thousand volts. Discharge of these voltages into semiconductor devices when
handling circuits can cause serious damage, which often may not be immediately
apparent but the reliability of the circuit will have been reduced.
The electronic circuits of ALSTOM T&D Protection & Control products are immune to
the relevant levels of electrostatic discharge when housed in their cases. Do not
expose them to the risk of damage by withdrawing modules unnecessarily.
Each module incorporates the highest practicable protection for its semiconductor
devices. However, if it becomes necessary to withdraw a module, the following
precautions should be taken to preserve the high reliability and long life for which the
equipment has been designed and manufactured.
1. Before removing a module, ensure that you are a same electrostatic potential
as the equipment by touching the case.
2. Handle the module by its front-plate, frame, or edges of the printed circuit
board. Avoid touching the electronic components, printed circuit track or
connectors.
3. Do not pass the module to any person without first ensuring that you are both
at the same electrostatic potential. Shaking hands achieves equipotential.
4. Place the module on an antistatic surface, or on a conducting surface which is
at the same potential as yourself.
5. Store or transport the module in a conductive bag.
More information on safe working procedures for all electronic equipment can be
found in BS5783 and IEC 60147-0F.
If you are making measurements on the internal electronic circuitry of an equipment
in service, it is preferable that you are earthed to the case with a conductive wrist
strap.
Wrist straps should have a resistance to ground between 500k – 10M ohms. If a
wrist strap is not available you should maintain regular contact with the case to
prevent the build up of static. Instrumentation which may be used for making
measurements should be earthed to the case whenever possible.
A LSTOM T&D Protection & Control strongly recommends that detailed investigations
on the electronic circuitry, or modification work, should be carried out in a Special
Handling Area such as described in BS5783 or IEC 60147-0F.