Installation P54x/EN IN/La4
MiCOM P543, P544, P545 & P546
(IN) 15-3
IN
1. RECEIPT OF RELAYS
On receipt, relays should be examined immediately to ensure no external damage has been
sustained in transit. If damage has been sustained, a claim should be made to the transport
contractor and ALSTOM Grid should be promptly notified.
Relays that are supplied unmounted and not intended for immediate installation should be
returned to their protective polythene bags and delivery carton. Section 3 of P54x/EN IN
gives more information about the storage of relays.
2. HANDLING OF ELECTRONIC EQUIPMENT
Before carrying out any work on the equipment, the user should be familiar with the
contents of the Safety Guide (SFTY/4L M/H11) or later issue, or the Safety and
Technical Data chapters of this Technical Manual and also the ratings on the
equipment’s rating label.
A person’s normal movements can easily generate electrostatic potentials of several
thousand volts. Discharge of these voltages into semiconductor devices when handling
electronic circuits can cause serious damage that, although not always immediately
apparent, will reduce the reliability of the circuit. The relay’s electronic circuits are protected
from electrostatic discharge when housed in the case. Do not expose them to risk by
removing the front panel or printed circuit boards unnecessarily.
Each printed circuit board incorporates the highest practicable protection for its
semiconductor devices. However, if it becomes necessary to remove a printed circuit board,
the following precautions should be taken to preserve the high reliability and long life for
which the relay has been designed and manufactured.
Before removing a printed circuit board, ensure that you are at the same electrostatic
potential as the equipment by touching the case.
Handle analog input modules by the front panel, frame or edges of the circuit boards.
Printed circuit boards should only be handled by their edges. Avoid touching the electronic
components, printed circuit tracks or connectors.
Do not pass the module to another person without first ensuring you are both at the same
electrostatic potential. Shaking hands achieves equipotential.
Place the module on an anti-static surface, or on a conducting surface that is at the same
potential as yourself.
If it is necessary to store or transport printed circuit boards removed from the case, place
them individually in electrically conducting anti-static bags.
In the unlikely event that you are making measurements on the internal electronic circuitry of
a relay 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 500 k to 10 M. If a wrist
strap is not available you should maintain regular contact with the case to prevent a build-up
of electrostatic potential. Instrumentation which may be used for making measurements
should also be earthed to the case whenever possible.
More information on safe working procedures for all electronic equipment can be found in
BS EN 100015: Part 1:1992. It is strongly recommended that detailed investigations on
electronic circuitry or modification work should be carried out in a special handling area such
as described in the British Standard document.
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