Juniper Networks M5 - Manual (Page 63)

Power Guidelines, Requirements, and Specifications
Site Electrical Wiring Guidelines
When planning the electrical wiring at your site, consider the factors discussed in the
following sections.
Distance Limitations for Signaling
Improperly installed wires can emit radio interference. In addition, the potential for damage
from lightning strikes increases if wires exceed recommended distances, or if wires pass
between buildings. The electromagnetic pulse (EMP) caused by lightning can damage
unshielded conductors and destroy electronic devices. If your site has previously experienced
such problems, you might want to consult experts in electrical surge suppression and
shielding.
Radio Frequency Interference
You can reduce or eliminate the emission of radio frequency interference (RFI) from your
site wiring by using 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.
Electromagnetic Compatibility
If your site is susceptible to problems with electromagnetic compatibility (EMC), particularly
from lightning or radio transmitters, you might want to seek expert advice. Strong sources of
electromagnetic interference (EMI) can destroy the signal drivers and receivers in the router
and conduct power surges over the lines into the equipment, resulting in an electrical hazard.
It is particularly important to provide a properly grounded and shielded environment and to
use electrical surge-suppression devices.
To comply with intrabuilding lightning/surge requirements, intrabuilding
wiring must be shielded, and the shield for the wiring must be grounded
at both ends.
Router Power Requirements
Table 9 lists the power requirements for various hardware components when the router is
operating under typical voltage conditions. For PIC power requirements, see the M5 and
M10 Internet Routers PIC Guide.
Prepare for Router Installation 43