Juniper SRX550, Hardware Manual

Page: 66 / 220

Table 14: Site Electrical Wiring Guidelines for the SRX550 Services Gateway
Guideline Site Wiring Factor
To ensure that signaling functions optimally:
•
Install wires correctly.
Improperly installed wires can emit radio interference.
•
Do not exceed the recommended distances or pass wires between buildings.
The potential for damage from lightning strikes increases if wires exceed recommended
distances or if wires pass between buildings.
•
Shield all conductors.
The electromagnetic pulse (EMP) caused by lightning can damage unshielded
conductors and destroy electronic devices.
Signaling limitations
To reduce or eliminate the emission of RFI from your site wiring:
•
Use twisted-pair cable with a good distribution of grounding conductors.
•
Use a high-quality twisted-pair cable with one ground conductor for each data signal
when applicable, if you must exceed the recommended distances.
Radio frequency
interference (RFI)
Provide a properly grounded and shielded environment and use electrical
surge-suppression devices.
Strong sources of electromagnetic interference (EMI) can cause the following damage:
•
Destroy the signal drivers and receivers in the device.
•
Conduct power surges over the lines into the equipment, resulting in an electrical
hazard.
TIP: If your site is susceptible to problems with EMC, particularly from lightning or radio
transmitters, you might want to seek expert advice.
Electromagnetic
compatibility (EMC)
CAUTION: Some ports are designed for use as intrabuilding interfaces only (Type 2
or Type 4 ports, the battery return connection is to be treated as an Isolated DC return
(that is, DC-I), as defined in GR-1089-CORE) and require isolation from the exposed
OSP cabling. To comply the NEBS requirements and protect against lightening surges
and commercial power disturbances, the intrabuilding port(s) of the device MUST NOT
be metallically connected to interfaces that connect to the OSP or its wiring. The
intrabuilding port(s) of the device is suitable for connection to intrabuilding or
unexposed wiring or cabling only. The addition of primary protectors is not sufficient
protection to connect these interfaces metallically to OSP wiring.
50