Juniper QFX5220, Руководство по оборудованию, Страница: 85 / 247

Table 28: Site Electrical Wiring Guidelines
Guidelines Site Wiring Factor
If your site experiences any of the following problems, consult experts in electrical surge
suppression and shielding:
•
Improperly installed wires cause radio frequency interference (RFI).
•
Damage from lightning strikes occurs when wires exceed recommended distances or
pass between buildings.
•
Electromagnetic pulses (EMPs) caused by lightning damage unshielded conductors and
electronic devices.
Signaling limitations
To reduce or eliminate RFI from your site wiring, do the following:
•
Use a twisted-pair cable with a good distribution of grounding conductors.
•
If you must exceed the recommended distances, use a high-quality twisted-pair cable
with one ground conductor for each data signal when applicable.
Radio frequency
interference
If your site is susceptible to problems with electromagnetic compatibility (EMC), particularly
from lightning or radio transmitters, seek expert advice.
Some of the problems caused by strong sources of electromagnetic interference (EMI)
are:
•
Destruction of the signal drivers and receivers in the device
•
Electrical hazards as a result of power surges conducted over the lines into the equipment
Electromagnetic
compatibility
QFX5220 Rack Requirements
QFX5220 switches are designed to be installed on four-post racks.
Rack requirements consist of:
•
Rack type
•
Mounting bracket hole spacing
•
Rack size and strength
Table 29 on page 89 provides the rack requirements and specifications for the QFX5220.
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