3Com 6000 Series Installation Manual page 20

20 C 3: I
HAPTER NSTALLING
ESD Preventive
Requirements
Electromagnetic
Environment
Requirements
Lightning Protection
Requirements
T R
HE OUTER
Figure 1 Harmful gas limits in an equipment room
Gas
SO
2
H S
2
NH
3
Cl
2
Despite careful considerations in preventing ESD in the design of the Router,
excessive static electricity may bring enormous damage to the card circuits and
even the entire Router.
On the communication network connected to the Router, the static electricity is
primarily introduced from the outside electrical fields, such as the outdoor
high-voltage power cable and lightning, and from the inside system, such as
indoor environment, floor material and the equipment frame. To avoid the
damage caused by the static electricity, you should ensure that:
The equipment is well connected to ground.
The equipment room is dust-proof.
There is adequate temperature and humidity.
You always wear the ESD-preventive wrist strap and clothes when contacting
the circuit board.
You place the removed circuit board upward on the ESD-preventive
workbench, or into a static shielded bag.
You hold the circuit board by the outer edge when observing or moving it, so
as to avoid direct contact with the elements on it.
All interference sources will affect the Router negatively in the conduction patterns
of capacitance coupling, inductance coupling, electromagnetic wave radiation,
and common impedance (including grounding system) coupling. To prevent the
interference:
Take effective measures against electricity net interference with the power
supply system.
Do not use the working ground of the Router together with the grounding or
lightning protection grounding device of the power equipment. Separate them
as far as possible.
Keep the Router far away from strong power wireless launchers, radar
launchers and high frequency and high-current equipment.
Use electromagnetic shielding if necessary.
Despite careful considerations have been taken in lightning protection in the
design of the Routers and measures have been adopted, excessive-degree of
lightning may still damage the Routers. To achieve the best lightning protection
effect, you are recommended to:
Keep the grounding wire of the PGND of the chassis in good contact with the
earth ground.
Max. (mg/m 3 )
0.2
0.006
0.05
0.01