PoE Plus
Enabling IP convergance
over twisted pair cabling
1
PoE Plus

Definition

Standards

Advantages/Drawbacks

Modelling

Cabling Options

Benefits of higher graded Cabling
2
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.
3
Working principle
4
USB/Firewire/PoE
Technology
USB2
Firewire 800
(IEEE1394a)
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?
PoE
PoE Plus
connector
Cross section
5
Actual applications

Power supply <13W

IP phone

Webcam

Wifi Accesspoint
6
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
7
Examples of power consumption
Power needed
Application
Wifi MIMO
13-20W
Biometric Access Control
Thin Clients
RFID Readers
Video IP Phones
20-30W
PTZ IP Cameras
Wimax Base Stations
Industrial Sensors
Workgroup switches
30-40W
Point of Sales
Information Kiosks
40-50W
Ultraportable Laptops
50-70W
Notebook Laptops
8
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
9
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?
10
Nexans Thermal Modell

3D Modelling Project in Nexans Research Center, France
Bundle 19 ca bles Ca t6 FTP modelling
Pa ra meters
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
11
Nexans Modelling Results (1)
Heating of Ethernet cable depending on the category
Heating of ethernet cable
60
55
insulation temperature (°C)

50
45
cat5e
40
cat6
cat7
35
30
25
20
0
1
2
3
4
5
current (A)
12
Nexans Modelling Results (2)
Heating of a bundle of cat5e ethernet cables
Heating of a bundle of ethernet cables
100
90
bundle temperature (°C)

37 cables
19 cables
80
7 cables
1 cable
70
60
50
40
30
20
0
1
2
3
4
5
current (A)
13
Nexans Modelling Results (3)
Comparison with experimenta l results
Experimental results are given with an precision of + / - 5°C
59
49
T layer1
49
Temperature (°C)
Temperature (°C)
54
T layer1 - Comsol
44
39
34
29
24
19
0
0,5
1
Current per wire (A)
1,5
T sheath
44
T sheath - Comsol
39
34
29
24
19
0
0,5
1
1,5
Current per wire (A)
- Power of 1A results in ~10° temperature rise in a
bundle of 19 cables
14
Results for Cat5e UTP cable (Worst Case)
20
Cat 5e UTP - 2 pairs energized
Ambient temperature: 24°C
Thermal conductivities [W/ (m.K)]
sheath (PVC)
0.1
insulation
0.3
copper
400
air
0.025
aluminium
160
Radiation emissivity:
0.8
Convection coefficient:
3 [W/ (m 2 .K)]

Conductor diameter:
0,52 [mm]
Max Temperature Increase (°C)
15
Cat5e UTP usable if bundle size <100
10
bundle 169
bundle 127
bundle 91
bundle 61
bundle 37
bundle 19
bundle 7
1 cable
5
0
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)
15
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
17
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)
18
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
19
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
20
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)
21
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!!!
22
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° !!
23
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°
24
Tolerate higher power levels
20
Cat 7 SFTP - 2 pairs energized
Ambient 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/ (m 2 .K)]
Conductor diameter:
0,59 [mm]
0,64 [mm] AWG22
Max Temperature Increase (°C)
15
10
bundle 169
bundle 127
bundle 91
bundle 91 AWG22
bundle 61
bundle 61 AWG22
bundle 37
bundle 37 AWG22
bundle 19
bundle 19 AWG22
bundle 7
bundle 7 AWG22
1 cable
1 cable AWG22
Cat7A cable would allow to
run ~ double power level
5
0
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.
25
Current per wire (A)
Larger Bundle Size
Relation of Cabling Grade and Size of Cable Bundle
15
Max Temperature Increase (°C)
Estima tion of 4 pa irs energized
Ambient temperature: 24°C
10
AWG 23
10 bundels = 331 cables
Cat6 UTP
Cat5 FTP
Cat6 FTP
Cat7 S/ FTP
Cat.7A S/ FTP
5
Cat7A AWG22
Cat.6 UTP Extrap.
AWG 22
10 bundels = 331 cables
Cat.5 FTP Extrap.
Cat.6 FTP Extrap.
Cat.7 Extrap.
Cat.7A Extrap.
Cat.7A AWG22 Extrap.
0
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
0 1 2 3 4 5
6
7
8
9 10 11 12 13 14 15 16
1 7 19 37 61 91 127 169 217 271 331 397 469 547 631 721 817
17
18 19
20
919 1027 1141 1261 26
Impact on distance
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.


UTP Insertion Loss

FTP Insertion Loss

Reduces by -0.6%/degree C

Reduces by -0.2%/degree C

Example: +10° for UTP

Example: +10° for FTP


Example: 60° for UTP


90m - 6% = 84,6 m link length
90m - 24% = 68,4 m link length

90m - 2% = 88,2m link length
Example: 60° for FTP

90m - 8% = 82,8 m link length
In High Temp envronments use higher cable grade to ensure 100m
distance (application dependend f.ex. Cat5 app over Cat6 cabling)
27
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
30
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
31