1. Challenges in ICT POE++ Design
Radhakrishnan Gopal
RCDD/ NTS; RPEQ ; MIE Aust CPEng NER
AECOM, UAE
radhakrishnan.gopal@aecom.com
BICSI Conference - Dubai 2016

2. Background
AECOM’s team > 85,000 people
• Architects, engineers, scientists , PM
• Trusted advisors to clients with projects in 152 countries
AECOM in the Middle East :
• More than 60 years
• Team of > 4,500 professionals
• Buildings, transportation, infrastructure, water and urban developments.
• UAE, Qatar, Oman, Kuwait, Saudi Arabia, Bahrain, Lebanon, Egypt, Jordan,
Iraq and Yemen
• Team backed by AECOM’s global resources
• Always look for talent
• www.aecom.com
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3. Challenges in ICT POE++ Design
• Introduction
• POE
• How it works
• Standards comparison
• Design challenges & recommendations
• Takeaway
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4. What is PoE?
• Power over Ethernet (PoE) - any system that safely pass electrical power
along with data to remote devices in an Ethernet network.
• High availability for data with power
• Uninterrupted services
• Faster deployment
• Convenient
• Possibly reduce CAPEX/OPEX
• Sustainable
• USB
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5. IEEE PoE Standards
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• IEEE standard: 2003
(IEEE 802.3af) – PoE, Type 1
• IEEE revised standard: 2009
(IEEE 802.3at) – PoE+, Type 2
• IEEE standard : 2016/2017
(IEEE 802.3bt), PoE++, Type 3, 4

6. Other PoE Standards
• TIA TSB – 184 A, temp increase < 10°C
• HDBase T- Alliance/CE – Compressed HD Video/ Audio, 10Gb/s, 100W
• ISO/IEC TR-29125 & CENELEC TR 50174-99-1-int cabling guidelines for
POE++
• Technology first Developed by CISCO in 2000 to support IP Telephony
deployments
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7. PoE Components
Types of devices used in a PoE environment
• PSE (Power Sourcing Equipment): device
that sends power and data to PD
– End span PSE – located at the end of
a link segment
– Mid span PSE – located in the middle
of a link segment, (Power injector)
• PD (Powered Device)
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8. PoE Components - PD
• Powered Device (PD), a device that draws power and receives data from a
PSE
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9. How it Works
Based on the IEEE PoE standards
• PSE start signaling to PD.
• PSE detects PD
• PSE negotiate the amount of power required
or available.
• PSE initially applies low voltage
• In return, PD present a specific signature to
PSE
• No signature detected, the PSE will NOT send
power, but WILL pass data
• If signature is detected, PD may optionally
present classification signature
• Power is supplied “ALLOWED WITHIN
PRACTICAL LIMITS” by the PSE
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10. Class 2 Power
Class 2 Power
• Defined within National Electrical Code (NFPA 70)
• 30VAC, 60VDC, 100VA
• Considered safe from a fire initiation standpoint
• Class 2 and 3 systems do not require the same wiring
methods as power, light, and Class 1 systems
• There are cases when separation is required between
these systems.
• Draft NEC 2017 is under development; “Premises
Powering of Communications Equipment over
Communications Cables”
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11. SELV Power
Safety (or Separated) Extra Low Voltage Power (SELV)
consists of following:
• For IT equipment, defined in IEC 60950-1
• Extra Low Voltage Circuit (< 35 VAC, <60VDC)
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12. Applications of PoE
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• Health care
• Military
• Commercial
• Security
• BMS
• ITS
• Rail systems
• SCADA
• Retail
• Banking
• Residential
• Justice
• Education
• Lighting

13. Transmission
IEEE 802.3:
Ethernet over Twisted Pair cables
802.3 af – PoE
• Min power at PSE output: 15.40 W
• Input power to the PD: 13 W (average)
• Safe nominal Volts DC: 40 VDC
• Maximum current (per pair): 350 mA
• Pairs used: 2 pairs each (1,2 & 3,6) for
data and (4,5 & 7,8) for power
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14. Transmission cont..
IEEE 802.3
Ethernet over Twisted Pair cables
802.3 at – PoE+
• Min power at PSE output: 30 W
• Input power to the PD: 25.5 W (average)
• Safe nominal Volts DC: 53 VDC
• Maximum current (per pair): 600mA
• Pairs used: 4 pairs for data; 2 pairs (4,5 &
7,8) for both data and power
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15. Transmission cont..
IEEE 802.3
Ethernet over Twisted Pair cables
802.3 bt – PoE++ or 4 Pair POE ( 4PPOE)
• Min power at PSE output: 100 W
• Input power to the PD: 49W (type3 and
96W type 4)
• Safe nominal Volts DC: TBA
• Maximum current (per pair): 600mA to
1000mA
• Pairs used: All 4 pairs for both data and
power
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16. Comparison
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17. Comparison – cont..
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18. Challenges – Temp Rise
What Contributes to heat generation?
• Bundle size ( loose lay)
• Power source
• Ambient air temperature
• Environmental conditions
• Type of pathways
• Number of energized
conductors/pairs
• Cable type
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19. Challenges – Temp Rise
• IEEE combined with TIA and ISO
standard bodies
• TIA developed profiles for Cat5e, 6, 6A
UTP in 100 cable bundles
• ISO data was corroborated
• Found Cat5e had the worst heat
dissipation performance & temp rise
• Hence Cat5 excluded from study
• Not recommended by TIA for new
install.
IEEE adapted baseline profile of Cat5e as
the worst case for Poe+ application
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20. Challenges – Temp Rise
• Typical result of testing on 100-cable
bundle
• Higher category cables show better
PoE++ performance
• Due to use of thicker wire gauges
• Shielded cables better than UTP
• Values shown here are conservative
Conclusion: Cat 6A shielded and above has
best performance
0
5
10
15
20
200 400 600 800 1000
TemperatureRise(degreesC)
Applied Current per Pair (mA)
Temperature Rise vs. Current
in 100-Cable Bundles
Category 5e Category 6A UTP
Category 6 Category 6A F/UTP
Category 6A UTP, slim profile Category 7A S/FTP
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21. Dispelling the Myth
Heat dissipation myth
• Screened or fully shielded system
will “trap” the heat generated by
PoE and POE+
• Cat6A, 7A shielded cable offers the
most desirable levels of heat
dissipation head room and current
delivery
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22. Impact - Derating Length
• Higher temp creates additional
insertion loss
• Need to de-rate the channel lengths
• Suggest to use vendor headroom
warranties to estimate - Cat7A
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23. Challenges – Arching
• Device disconnections can’t be anticipated
• When plug is removed from jack “Unmating pairs
under load” produces an arc
• The applied current transitions from flowing
through conductive metal to air, before
becoming an open circuit
• Arcing causes corrosion and pitting damage on
the plated contact surface
• TIA standards recommend 50-µm gold /
palladium plated tines
• IEC 60512-99-00 specifies a test method @ 100
insertions and removals under load conditions of
55V DC and 600 mA
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24. Eng. Design Considerations
• In POE++, 600mA and above current generate heat in the plant
• Excessive temp rise:
– cannot be tested /mitigated in the field
– Cause premature aging of jacket material
– Increased insertion loss
– Create bit errors
• Type and length of cable
• Effect of the bundle sizes
• Arching
• Active equipment
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25. Eng. Design Questions to Ask
Apart from all the normal design considerations:
• Is the ambient temperature at least 10°C below cable operating temp?
• Are we using the right cable? E.g.: Cat6A shielded or above?
• Do I need to de-rate my maximum channel length?
• What are the maximum bundle sizes for the cable in use?
• Do the connectors meet IEC 60512-99-001?
• Are the PSE and PD selected supporting POE+ and are they Poe++ ready?
• Are the vendor recommendations followed?
• Are the coordination with other design services in place?
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26. References / Acknowledgment
• PoE plus operating efficiency - How to keep a hot application running cool; and other POE
articles and all graphs and some images - www. Siemon.com;
• Inputs from Rajendranath P, Topnet, UAE
• Inputs from Betty Bezos, Bezos technology
• Inputs Prem Rodrigues, Narender Vasandhani, The Siemon company ltd.
• Cisco Universal Power Over Ethernet: Unleash the Power of your Network – White paper
• Introduction to PoE and the IEEE802.3af and 802.3at Standards ; Morty Eisen, Marcum
Technology
• Inputs from Lawrence McKenna, Wood & Grieve Engineers; www.wge.com.au
• Presentation on POE by Frank Straka, Panduit, image slide p.16; www.panduit.com,
• PoE and other technologies are pushing powered-device wattages ever-higher; BY Patrick
Mclauglin; Cabling Installation and Maintenance ; Penn Well Corporation
• Answering challenges to structured cabling in buildings; Nexans white paper, Jan 2013
• www.nfpa.org
• Inputs AECOM team
• IEEE, TIA standards, various
• Linked-in - Slide share, slide p.27
• www.Bicsi.org
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27. Emerging Technology
• Power over Fiber( POF),
tested to 60W in lab
• Witricity (magnetic coupled
resonance power transfer)-
60W to 30m via magnetic
fields
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28. Challenges in ICT POE++ Design
Thank you
radhakrishnan.gopal@aecom.com
www.aecom.com
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