1

PoE Plus

Enabling IP convergance over twisted pair cabling

2

PoE Plus

Definition

Standards

Advantages/Drawbacks

Modelling

Cabling Options

Benefits of higher graded Cabling

3

PoE : what is it?

Power over Ethernet describes any system to transmit electrical power along with data over standard twisted-pair cable in an Ethernet network.

The IEEE802.3af standard provides the capability to deliver both power (max 12.95W) and data over standard ethernet Cat.3/Cat.5 cabling.

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Working principle

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USB/Firewire/PoE

Technology USB2

Firewire 800

(IEEE1394a)

PoE PoE Plus

Power transmitted

(W)5 45 12.95 25

Max length(m)

5 4.5 100 100

Data Rate 480 Mb/s 800 Mb/s 1 Gb/s 10 Gb/s?

connector

Cross section

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Actual applications

Power supply <13W

IP phone

Webcam

Wifi Accesspoint

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Future applications?

Charge of a laptop

Providing both power supply and internet connection in trains and planes

Peripheral devices : screen, printer, home theatre…

Power backup for PC

Power supply for specific PC

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Examples of power consumption

Power needed Application

13-20W

Wifi MIMO

Biometric Access Control

Thin Clients

20-30W

RFID Readers

Video IP Phones

PTZ IP Cameras

Wimax Base Stations

Industrial Sensors

30-40W

Workgroup switches

Point of Sales

Information Kiosks

40-50W Ultraportable Laptops

50-70W Notebook Laptops

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Advantages

Advantages :

Only one cable to carry datas and power

Up to 100m

Ethernet connector standard (RJ45) is widespread

Compatible with Gigabit Ethernet (1000BASE-T)

centralized backup power

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Challenges and Answers

Learn from the challenges at the beginning and how they have been answered

Data cables are not made for this use (copper conductors are too thin, 24 AWG = diameter of 0.5106 mm)

Higher power levels over thin copper cables lead to temperature rise in cables What are the limits ?

Do we need new cables?

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Nexans Thermal Modell

3D Modelling Project in Nexans Research Center, France

Bundle 19 cables Cat6 FTP modelling

Current : 350 mA per wire

Bundle 19 cables Cat6 FTP modelling

Current : 350 mA per wire Ambient temperature = 24°C

Thermal conductivities (W/m.K) :

- air : 0.025

- copper : 400

- aluminium : 160

- insulation : 0.3

- PVC sheath : 0.1

- cross : 0.4

Thickness of alu screen : 25µm

Radiation emissivity : 0.8

Convection coefficient : 3

Parameters

Ambient temperature = 24°C

Thermal conductivities (W/m.K) :

- air : 0.025

- copper : 400

- aluminium : 160

- insulation : 0.3

- PVC sheath : 0.1

- cross : 0.4

Thickness of alu screen : 25µm

Radiation emissivity : 0.8

Convection coefficient : 3

Parameters

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Nexans Modelling Results (1)

Heating of Ethernet cable depending on the category

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Nexans Modelling Results (2)

Heating of a bundle of cat5e ethernet cables

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Nexans Modelling Results (3)

Comparison with experimental results

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24

29

34

39

44

49

54

59

0 0,5 1 1,5

Current per wire (A)

Tem

pera

ture

(°C)

T layer1

T layer1 - Comsol

19

24

29

34

39

44

49

54

-0,1 0,1 0,3 0,5 0,7 0,9 1,1 1,3 1,5

Current per wire (A)

T layer2

T layer2 - Comsol

19

24

29

34

39

44

49

0 0,5 1 1,5

Current per wire (A)

Temp

eratur

e (°C)

T sheath

T sheath - Comsol

Experimental results are given with an precision of +/- 5°C

- Power of 1A results in ~10° temperature rise in a bundle of 19 cables

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Results for Cat5e UTP cable (Worst Case)

0

5

10

15

20

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5

Current per wire (A)

Max

Tem

per

atu

re Incr

ease

(°C

)

bundle 169bundle 127bundle 91bundle 61bundle 37bundle 19bundle 71 cable

Cat 5e UTP - 2 pairs energizedAmbient temperature: 24°C Thermal conductivities [W/(m.K)] sheath (PVC) 0.1 insulation 0.3 copper 400 air 0.025 aluminium 160Radiation emissivity: 0.8

Convection coefficient: 3 [W/(m2.K)]Conductor diameter: 0,52 [mm]

Cat5e UTP usable if bundle size <100

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ISC SC25 / POE Ad Hoc Result

ISO SC25 Temp. Rise Data provided to IEEE

For 100 cable bundles Cat5 UTP minimum: all pairs energised

Temp Rise (in °C)

allowed current (mA) per pair

5° 420

7.5° 550

10° 600

12.5° 680

15° 720

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IEEE Choice

Maximum acceptable Temperature Rise = 10°

Max maximum rating for cable = 60°

Max temp for equipment / ambient temperature = 45 ° = 15° Max.

Including some tolerance finally 10° Temperature Rise accepted

Leads to limitation to 25 Watts

10° TR equals 600 mA

using 57 Volts 24/25 Watts Limitation (using 2-pairs only)

50 Watts target only achievable with 4 pairs but this is patented technology

No licenses available (PowerDesign)

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IEEE Standards

The existing standard : IEEE802.3af (PoE)

48V DC over two pairs of cat3/cat5 ethernet cable

400mA per pair

12.95W (with losses)

The future standard : IEEE 802.3at (PoE Plus)

Uses the up to four pairs of cat5e cable

57V DC

600mA per pair

Up to 25.5W

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ACHIEVEMENT

FINALLY:

POE PLUS is possible with ALL Copper LAN Cables !! IEEE Standard based on worst case CAT5e UTP

No need for ‚thick‘ cables

Big Achievement:

Run POE PLUS and IP Convergance over existing LAN cabling

..but some cabling can support it better than others..... Get around some limitations and compromises made to enable worst case

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Benefits of better cable

Let us look into benefits of better cabling. This would potentially allow

Limit the temperature rise (and save energy for cooling(?))

Tolerate higher power levels (some equipment oversubscribes)

To use larger bundles than 100 cables or even “bundles of bundles”

Tolerate environments at higher temperature without reaching the 60° limit when using PoE+

Keep maximum distances (100m)

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POE /P 2 pairs

Temperature Rise per cable grade remember to double temperature rise due to 4 pairs (IEEE) instead of 2 pair (used

in comparison these chart) Almost linear behaviour from 2-4 pair!!!

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Temp Rise per Cable Grade

Approximate Temperature Rise in 127 cable bundles

2 pairs energised with 0.35A per wire

~4 pairs energised with 0.35A per wire

IEEE standard

LANmark-5 UTP 6.25 14°

LANmark-6 UTP ~4.5 10°

LANmark-5 FTP 3.5 8°

LANmark-6 F2TP ~3 7°

LANmark-7 S/FTP 2.5 6°

LANmark-7A S/FTP AWG23

1.6° 4°

LANmark-7A S/FTP AWG22

1.1° 3°

Difference between AWG 23 and AWG 22 cables is 1° !!

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Acceptable Ambient Temperature

Maximum Peak Ambient Temp compatible with

POE +

~4 pairs energised with 0.35A per wire

Acceptable Peak Temp from Cabling Point of

view(Operating range)

UTP Cat.5 14° 46°

LANmark-6 UTP 10° 50°

LANmark-5 F1TP 8° 52°

LANmark-6 F1TP 7° 53°

Cat.7 S/FTP 6° 54°

LANmark-7A 4° 56°

LANmark-7A 1500 3° 57°

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Tolerate higher power levels

0

5

10

15

20

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5

Current per wire (A)

Max

Tem

per

atu

re Incr

ease

(°C

)

bundle 169bundle 127bundle 91bundle 91 AWG22bundle 61bundle 61 AWG22bundle 37bundle 37 AWG22bundle 19bundle 19 AWG22bundle 7bundle 7 AWG221 cable1 cable AWG22

Cat 7 SFTP - 2 pairs energizedAmbient temperature: 24°C Thermal conductivities [W/(m.K)] sheath (HFFR) 0.4 insulation 0.3 copper 400 air 0.025 aluminium 160 (40µm)Radiation emissivity: 0.8 Convection coefficient: 3

[W/(m2.K)]Conductor diameter: 0,59 [mm] 0,64 [mm] AWG22

Cat7A cable would allow to run ~ double power level

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Larger Bundle Size

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 201 7 19 37 61 91 127 169 217 271 331 397 469 547 631 721 817 919 1027 1141 1261

Relation of Cabling Grade and Size of Cable Bundle

0

5

10

15

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

No of layers in bundle

Max

Tem

pera

ture

Incr

ease

(°C)

Cat6 UTP

Cat5 FTP

Cat6 FTP

Cat7 S/FTP

Cat.7A S/FTP

Cat7A AWG22

Cat.6 UTP Extrap.

Cat.5 FTP Extrap.

Cat.6 FTP Extrap.

Cat.7 Extrap.

Cat.7A Extrap.

Cat.7A AWG22 Extrap.

Estimation of 4 pairs energizedAmbient temperature: 24°C

AWG 2310 bundels = 331 cables

AWG 2210 bundels = 331 cables

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Impact on distance

UTP Insertion Loss

Reduces by -0.6%/degree C

Example: +10° for UTP 90m - 6% = 84,6 m link length

Example: 60° for UTP 90m - 24% = 68,4 m link length

FTP Insertion Loss

Reduces by -0.2%/degree C

Example: +10° for FTP 90m - 2% = 88,2m link length

Example: 60° for FTP 90m - 8% = 82,8 m link length

All International Standards specify insertion loss requirements at 20° C and have quantified a small increase of attenuation of less than 0.2%/degree C for shielded cable and up to 0.6%/degree C for unshielded cable.

In High Temp envronments use higher cable grade to ensure 100m distance (application dependend f.ex. Cat5 app over Cat6 cabling)

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Impact for Office Cabling

High Impact estimated for Office Cabling where a frequent use of POE/P can be expected

Devices like VoIP Telephones, Sensors, Printers, thin clients, new generation laptops require pontially fully energised large bundles of cabling

Bundles Size in horizontal cabling = typically 100 FD, often larger than 100 cables

1 Floor of 50 users equals 150 cables at 3 drops /users

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Summary

POE/P is a key technology to enable IP Convergence

Cat5e UTP cabling is required as a minimum

10° temperature rise at 600mA per pair

Max. bundle size = 100

Better cabling Higher Grade (Cat 6 and Cat7) or shielded cable allows to

Lowering the expected temperture rise

Use larger bundles sizes

Tolerate higher power level

Save energy for cooling in comms rooms

Enable full distance of 100m