Cabling For Next-Generations PoE Applications

Dimitris Filippou Technical Director, Ltd.

IEEE Member, BICSI Country Chair, ELOT Technical Committee TC93 Member,

CENELEC TC215 Delegate of Greek National Committee, CENELEC TC215 WG1, WG2 & WG3 Member dimitrisfilippou@bicsi.org, dfilipp@ieee.org

Dimitris Filippou

Dimitris Filippou

Technical Director I2QS Ltd.

Tel.: 0030 210 6781087

Mob.: 0030 6945 876240

BICSI E-mail: dimitrisfilippou@bicsi.org

IEEE E-mail: dfilipp@ieee.org

E-mail: dfilippou@i2qs.com

Standards Activity

Member TC215 WG1: Cabling Design

TC215 WG2: Cabling Installation – QA and Installation Practices

TC215 WG3: Facilities and Infrastructures for Data Centres

Delegate TC215: Electrotechnical Aspects of Telecommunications Equipment

Member TC93: Internal Networks of Electronic Communications for

Houses and Buildings

Country Chair

Member Standard Committee for Cabling Design & Installation

Remote Powering Devices

Remote powering devices is NOT a new concept…

Remote Power Technology Evolution

1995 1980 1995 1999 2003 2009 2010 2011 2013 2013

ISDN USB ≤4.5W

IEEE 1394 Firewire

≤45W

PoL ≤10W

IEEE 802.3af

PoE

IEEE 802.3at

PoE+

HDBaseT & LED

Lighting

Cisco UPOE

Proposed IEEE

802.3bt 4PPoE

USB 3 ≤100W

Remote Powering - Market Potential

Sources: VDC Research IMS Research - Jenalea Howell http://seekingalpha.com/article/101408‐the‐global‐lighing‐market-by‐the‐numbers‐courtesy‐of‐philips and other research reports Gartner Forecasts, BT Turret, Cisco Partners

Power Over Ethernet (PoE)

• There are 3 types of devices used in PoE environment:

– Power Sourcing Equipment (PSE) – Endspan.

– Power Injector (PI) – Midspan.

– Powered Device (PD).

PoE Components Definition

• Power Sourcing Equipment (PSE) - specially configured power supply designed to provide power safely to a valid Powered Device.

• Powered Device (PD) - End Device that accepts and uses power from the Ethernet cable for its operation.

• Power Injector (PI) – Type of PSE and in simple terms is typically a pass through box which adds PoE power, also known as Midspan.

IEEE 802.3xx PoE Principles

IEEE specifies two methods for PSE to provide power

Method A is compatible with 10/100/1000BASE-T and transmits power simultaneously with data using the center tap of the transformer.

Method B takes advantage of the spare pairs in twisted-pair Ethernet cables is an easy approach but is only compatible with 10/100BASE-T applications.

IEEE 802.3xx PoE Principles (cont.)

• IEEE 802.3af/at-2012 Clause 33 Power Injection – Requires 2-pairs. – Power is injected on either pairs 1-2,

3-6 or pairs 4-5, 7-8 (Alternative A or Alternative B configuration).

– Allows Alternative A or Alternative B but not both.

• IEEE P802.3bt 4-Pair Power Injection Power injected on both 1-2, 3-6 and 4-5, 7-8 pairs (all pairs are powered up).

Power Over Ethernet (PoE) Standards

ANSI/TIA

Application 802.3af 802.3at

P802.3bt

Cabling Performance EN 50173-1 11801 568-C.2

Power delivery over twisted pair cabling

TR 50174-99-1 TR 29125 TSB 184-A

Connector testing under electrical load

EN 60512-99-1 IEC 60512-99-1

Safety EN 60950-1 IEC 60950-1

Evolution of PoE Application Standards

2003 2009 2016?

Standard IEEE

802.3af IEEE

802.3at IEEE P802.3bt

Acronym PoE PoE+

4PPoE

Type 1 Type 2 Type 3 Type 4

2 Pairs 4 Pairs 4 Pairs 4 Pairs

Source Current (max. per pair set)

350mA 600mA 350mA 300mA 600mA 960mA

Source Voltage (min.) 44V 50V 44V 50V 50V 52V

Source Power (max.) 15.4W 30W 15.4W 30W 60W 100W

DC Loop Resistance per Conductor (Ω/100m)

40 25 25 25 25 25

IEEE 802.3 4PPoE – Key Objectives

• 4-Pair PoE.

• Comply to limited power source and SELV requirements in IEC 60950-1: – An SELV circuit is so designed and protected that, under normal and single fault

conditions, its voltages do not exceed a safe value (42.4VACpeak or 60VDC) between any two points of the circuit or to earth.

• Support of operation over the following channels that have DC loop resistance of no greater than 25Ω: – Category 5e/Class D or better cable and components.

• For same load current, 4-pair is more efficient that 2-pair delivery.

• Today PoE supports 10BASE-T, 100Base-Tx, 1000BASE-T. Study feasibility of PoE support for 10GBASE-T.

• Maintain backward compatibility with IEEE 802.3-2012 Clause 33.

PoE Types and Classes

IEEE P802.3bt Timeline

IEEE 802.3 Cabling Requirements - Channel

10BASE-T 100BASE-Tx 1000BASE-T 10GBASE-T DTE Power

Frequency (MHz) 100 100 100 500 -

Insertion Loss (IL) -

NEXT -

Return Loss (RL) -

ACR-N -

ACR-F -

ANEXT -

AFEXT -

Loop Resistance

Intra Pair Resistance Unbalance

Pair-to-Pair Resistance unbalance

Resistance leads to heating, increased IL and power loss at PD. Resistance Unbalance leads to disruption of the data traffic.

Loop Resistance

R1 + R2 < 25Ω

Intra Pair Resistance Unbalance

Resistance Unbalance < 3%

Source: IEEE 802.3-2012, Figure 33-4

R1 = 9.1Ω

R2 = 9.1Ω

Loop Resistance = 18.2Ω, Resistance Unbalance = 0%

Intra Pair Resistance Unbalance (cont.)

Resistance Unbalance < 3%

Source: IEEE 802.3-2012, Figure 33-4

R1 = 10.4Ω

R2 = 7.8Ω

Loop Resistance = 18.2Ω, Resistance Unbalance = 14%

Pair-to-Pair Resistance Unbalance

R4, 5 = 2,48Ω

R7, 8 = 2,37Ω

Pair-to-Pair Resistance Unbalance = (2.48-2.37)/(2.48+2.37)=(0.11/4.85)=2.3%

Pair-to-Pair Resistance Unbalance (cont.)

Pair-to-Pair Resistance Unbalance < 7%

Remote Powering Cabling – Main Concerns

• Increases in the operating temperature of the cable.

• Damage to connecting hardware contacts where mating and de-mating occurs while power supply current is flowing.

• The associated increase of channel attenuation/ insertion loss due to the increased temperature of installed cables.

TR 50174-99-1 TR 29125

Fixed – Free Connector Mated Connection

Source: Belden Inc.

CENELEC TR 50174-99-1

• Provides requirements and recommendations concerning limits for the application and operation of remote powering using balanced cabling (as defined in EN 50173-1).

• Class D or higher. • Applying different installation conditions:

– Open air; – Supported tray; – Conduit with open ends; – Conduit with sealed ends.

• Provides both a mathematical model and a testing protocol methodology.

Test Rig: Cable Heating

T1, T2a and T3

T2b

T2c

T2d

Thermocouples

Ambient

”perfect” bundle

T3 Ta 0,6

0,05 m

1,2 m 1,2 m

0,6

0,05 m

T2x T1

Current feed using 37 cable bundle

Cable 1 Cable 2

……...

Cable 37

ic

ic

Installation Conditions

Thermal measurements

to date on ventilated

bundles

Partially ventilated

Unventilated Insulated

Reflects real installation practices

Installation Conditions (Cont.)

Supported Tray Open Air

Installation Conditions (Cont.)

Conduit with sealed ends Open Conduit

CENELEC TR 50174-99-1

Cable bundles of N ≤ 24 should be installed. Air gaps should be provided between bundles to allow for ventilation. • Early research has shown that the spacing of cable bundles by a

minimum of 15mm reduces temperature rises to that of a single bundle.

The lengths and types of pathways and systems and the installation configuration (e.g. presence of air gaps) of cable bundles should be documented for future reference.

2 1 3 2 1 3 2 1 3

Bundles without gap Bundles with 8mm gap Bundles with 15mm gap

IEEE 802.3az

• Energy Efficient Ethernet (EEE) – Released on 2010. Enhancements to Ethernet over Twisted-Pair, that allows less power consumption during periods of low data activity.

• Energy Efficient PoE (EEPoE) – Increase efficiency by 94% transmitting over the same cable, powering IEEE 802.3at compliant devices in synchronous four pair.

• Projected Power savings of 45%-80% (Switches, Routers, APs).

IEEE 802.3az (cont.)

• Allows each port on a switch (PSE) to power down into a standby or “sleep” mode when there’s no activity.

• Switches detect cable length of each link and adjust the power accordingly.

• Approximately 4.5W/port is wasted on a Cat.5/Cat.6/Cat.6A cable after 100m.

IEEE 802.3az (cont.)

IEEE 802.3az (cont.)

Summary

• PoE market continues to expand as increased power levels support broader range of powered devices: – 4-Pair PoE (IEEE P802.3bt) culminates this trend to nearly

100W per cable.

• Recommendations for cabling installation in standards bodies (ISO/IEC, CENELEC) being re-evaluated based on the effects of increased power and heating.

• Installation conditions (tray, open or sealed conduit etc.) affect heating.

• Record keeping recommended to ensure installation can support remote powering to desired level.

Questions

Dimitris Filippou Technical Director, Ltd.

IEEE Member, BICSI Country Chair, ELOT Technical Committee TC93 Member,

CENELEC TC215 Delegate of Greek National Committee, CENELEC TC215 WG1, WG2 & WG3 Member dimitrisfilippou@bicsi.org, dfilipp@ieee.org