Ethernet Cabling Guidelines
C Layer 2 switch • If a ground stud is provided, connect it to the ground bar bus (G) with a
dedicated ground wire. Use the wire gauge specified by the manufacturer
• Powered hubs supply IP Phones with power through the Ethernet cable
either through the spare wires or the signal pairs. IP Phones that have
power adapters do not use powered hubs.
• If a ground stud is provided, connect it to the ground bar bus (G) with a
dedicated ground wire. Use the wire gauge specified by the manufacturer
D Powered hub • Powered hubs supply IP Phones with power through the Ethernet cable
either through the spare wires or the signal pairs. IP Phones that have
power adapters do not use powered hubs.
• If a ground stud is provided, connect it to the ground bar bus (G) with a
dedicated ground wire. Use the wire gauge specified by the manufacturer
E Protected power system • Dedicate the use of the power outlets to the equipment in the equipment
room only.
• Ensure that the power outlets in the equipment room are wired for 15 Amp
service directly to the electrical service panel with ideally one circuit
breaker per outlet.
• If the site is configured with resilient IP phones, ensure that the 3300
controllers are powered by dedicated power bars.
• Switching power supplies common in computers and telecommunications
equipment generate noise voltages, known as harmonics. Use oversize
neutral conductors to minimize harmonics.
• Ensure that conduits include a dedicated copper ground
F Cable • Ensure that the maximum cable runs do not exceed 333 ft. (100 m).
G Ground bar bus • Use a ground bus bar that is ¼ inch thick and 2 inches wide and long
enough to accommodate the grounding for all the rack-mounted
equipment
• Recommended bus bar is ANIXTER part number 179639
• Mount the bus bar on the wall with insulated standoffs
• Use compression style fittings to fasten the ground wire lugs to the bar
• Connect the bus bar to the main building ground with a 6 AWG copper,
stranded, green-colored cable.
• For grounding specifications see ITU-T K.27 “Building configurations and
earthings inside a telecommunications building” and ANSI/TIA/EIA-607
H Protected rack-mount
power strip
• If you cannot provide dedicated 15 Amp power outlets for each unit in the
rack, mount a surge-arresting power strip on the front or rear of the rack.
• Recommended model is the Surge Arrest - Rack Mount model from
American Power Conversion. The ground from the rack forms part of the
shield for the power strip.
• Plastic floor type models are not recommended because they are more
likely to be turned off by accident.
Caution: Power bars have a circuit breaker. If the circuit breaker is tripped
due to a power surge, the power to all the outlets on the power bar is shut
off. If the site supports resilient IP Phones, ensure that the controllers are
plugged into different power bars.
Table 87: Equipment Room Cabling Guidelines (continued)
Connection Guidelines
Page 2 of 3
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