Transcript PPT: The 607 Standard

Network Cabling Systems
Power Protection, Grounding and Bonding
Updated Jan 2014
©[email protected]
1
Ground
A Ground is ‘a conducting
connection, whether intentional
or accidental, between an
electrical circuit or equipment
and the earth, or to some
conducting body that serves in
place of the earth.’
image: wiki
◦ NEC Article 100
The earth is considered electrically neutral (does not
carry either a positive or negative charge).
2
Bonding
Bonding is ‘the permanent
joining of metallic parts to
form an electrically
conductive path that will
ensure electrical continuity
and the capacity to conduct
any fault current that is likely
to be imposed.’
image: www.navasola.com
◦ NEC Articles 100 and 250-70
3
REASONS FOR GROUNDING
4
Noise: Electromagnetic Induction

Principle:
◦ Magnetic flux lines crossing a
conductor will induce
current.
◦ There must be relative
motion. This is created by
the alternating current of the
source.
Source Current
Induced Current
5
Sources of Noise

Ambient Noise:
◦ Background, steady, predictable noise.
◦ The most common source of ambient noise is the
building’s electrical system

Transient Noise:
◦ Irregular and unpredictable noise.
◦ Transient noise is often difficult to pinpoint.
◦ Likely sources are switching circuits when current
draw changes abrupty
6
Noise

The currents from power and
communication cabling will
induce current on all metallic and
conductive elements in the
vicinity including cable shields,
computer chassis, cable trays,
conduit, cabinets, racks and other
support systems.

The noise induced on these
elements may eventually spread
the effects of noise onto other
communication devices and
cables.
Reason: Noise Control

Connecting all conductive elements of the data
communications infrastructure to an effective
grounding system will conduct the induced
current to earth ground and remove its potential
for creating additional noise.
8
Static Electricity
Static Electricity is an electrical charge that has
accumulated on an object.
 Static electricity develops whenever objects
move, including a person or a person’s clothes.

◦ Can easily exceed 10,000 Volts.

Humans can feel about 3000 Volts.
9
Hazards of Static Electricity

Equipment damage
image: mult sources
◦ Static charges as low as 10V or less can permanently
damage communication and electronic components
and equipment

Ignition
◦ Static discharges can ignite flammable liquids and
gases.

Other
◦ Static discharge through a person may cause involuntary
movement and injury via secondary contact.
◦ Items may tend to stick together creating a nuisance.
10
Working with Static in Mind

Ground yourself and your equipment (wrist straps and
mats)
◦ Do not ground yourself when working near high voltage
sources.
Don’t let anyone touch you when working on circuit
boards or other static sensitive items.
 Transport electronic components and cards in staticshielding bags
 Keep static-inducing non-conductors such as styrofoam
away from electronics

11
Reason: Effective Static Control
Use static control systems designed to connect
to earth ground
 Connect the static control to an effective ground
to neutralize the static charge

image: support.sonus.net
12
Electrical Faults

An electrical fault in an electrical cable or
equipment may cause chassis or other
conductive components to be energized, creating
a significant hazard
◦ Electrical shock hazard to people touching the
energized component
◦ Equipment damage
◦ Fire
13
Reason: Electrical Fault Control

Two elements of a good electrical fault protection:
◦ An effective ground system that will safely conduct the
electrical energy to earth ground
and
◦ A fuse or breaker on the ‘hot’ side that will open the electrical
circuit should there be a short circuit to ground
14
Lightning
When lightning strikes it carries both a very
high voltage and a large amount of current
 Lightning strikes are somewhat unpredictable
 Indirect lightning damage can occur when it
follows a cable, fence or other conductive path

image: blog post
15
Effect of lightning
striking an
underground cable.
Note the sand has
been turned to glass,
known as fulgurite.
images: plaza.ufl.edu
16
Reason: Lightning Control
Ensure an adequate lightning control system in in place,
including an independent and effective grounding
connection
 Follow a safety plan than minimizes the exposure to a
primary or secondary lightning strike
 Employ an effective building entrance protection for all
metallic elements of the communication cabling

17
Effective Grounding
18
Establishing an Effective Ground

The earth is a conductive body, and is
considered electrically neutral (neither a positive
nor a negative charge).

Establishing an effective ground is important for
safety and systems performance
19
Grounding Electrode System

A grounding electrode is a metallic conductor
(rod, pipe, plate, etc.) in contact with the earth

The system may be a network of connected
electrodes

Its installation and use is defined in the Electrical
Code
Not the responsibility of a communications systems designer
except when needed for communication-only applications.
20
Grounding Electrode Systems

Normally consist of:
◦ Grounding electrode
 Rod, plate, pipe or other conductor that is in constant and
lengthy contact with the ground
◦ Grounding wire
 Large gauge copper conductor, typically stranded, may not
have a jacket, should be continuous
◦ Bonding devices
 A clamp or other means of attaching the grounding wire to
the grounding electrodes and to the items that require
grounding
21
Grounding
Exterior Grounding Electrode System
Ground Wire
Building
Ground Clamp
Image: PRGodin
Earth
Grounding
Electrode
22
Typical Ground in a House

In this image 2
ground wires are
attached via a
grounding clamp to
the metal water pipe
Image: PRGodin
23
Typical Ground in a House

This image demonstrates a ground wire clamped
to a metal gas pipe.
Image: PRGodin
24
image: www.electrical-contractor.net
Exterior Gounding
25
Codes and Grounding

Grounds are an important part of electrical
safety and their installation is described in the
electrical code. Each municipality may make its
own rules regarding grounding.

An independent grounding system may be
required for lightning protection. This system
should not be used for grounding data
communications equipment.
26
Ground Types

There are 3 basic types of grounds in communication
systems:
◦ Earth ground: primary role is safety. It is also the absolute
reference point for voltage. The potential of an earth ground is
considered 0 Volts.
◦ Chassis ground: usually used for safety and for noise shielding.
Meant to have a potential of 0 Volts.
◦ Common ground: a point of reference for signals and voltages
within a circuit. A relative reference point for voltage, it’s often
not connected to earth or chassis ground.
Earth Ground
Chassis Ground
Common Ground
27
Effective Grounds

Good earth connection
◦ Proper installation of the electrodes
◦ Good soil conditions

Low resistance path
◦ Larger AWG of wire
◦ Good bonding connections

Short path
28
Electrical Overview
29
Electrical Basics

3-wire system in North America
◦ Neutral is wider slot
 The neutral is connected to earth ground at the transformer
 Forms the return path for current
 Not safe as ground
◦ Hot wire is narrower slot
 The Hot is connected to the transformer
 Current and voltage source
◦ Ground is the round hole
 The Ground is connected to the building ground
 Must not carry current under normal conditions
30
Electrical Supply
The electrical voltage used in N. America is
120VRMS
 This voltage may vary based on location and on
overall system load:

◦ As low as 110V during peak hours (5PM-10PM)
◦ As high as 130V overnight

Although electrical supply in N. America is fairly
reliable some problems may occur
31
Blackouts

Complete power outage

Have multiple causes (from squirrels to auto accidents
to power generation problems)

Back-up Power Supplies and UPS’s are a
solution
What type of data communications-related damage
could occur with blackouts?
http://www.powerware.com/blackouttracker/default.asp?cx=5&CC=1
32
Brownouts and Surges

Decreases or increases in voltage that can last a
considerable amount of time

Brownouts may occur in situations where too many
power plans are off-line

Back-up Power Supplies and UPS’s (Uninterruptable
Power Supplies) are a potential solution
What type of data communications-related damage
could occur with brownouts or surges?
33
Spikes and Drops

Last between 0.5 and 100 microseconds

Amplitude of over 100% peak line voltage or a
cycle completely missing

Typically caused by EMPs from high load
switching, electrical storms and utility
switching

Quality surge suppressors and UPS can offer
protection
34
Harmonics
Secondary signal on top of the regular waveform
with a magnitude ranging from 15 to 100% of
nominal line voltage
 Increases power supplied to load
 Caused by:

◦ Power transformers, motors and motor drives
◦ Non-linear loads (loads that vary in their current
draw) such as power supplies and dimmers

Dedicated circuits or UPS equipment will reduce
harmonics
35
Reducing Electrical Problems

Maintain isolated circuits for data communication
equipment
◦ The symbol for an isolated ground is an orange triangle. Often
the entire receptacle is orange
◦ Isolated grounds must be professionally installed
◦ Do not allow other appliances to connect to an open outlet

Use good quality surge suppressors
◦ Surge suppressors often have a limited lifespan
Use line filters
 Consider a UPS for critical systems

◦ Variety of options available
Isolated Ground Symbol
(Orange Color)
36
Electrical Safety
image: http://www.nachi.org/forum/
37
Safety

A primary responsibility of the communication systems
installer is safeguarding personnel, property and
equipment from “foreign” electrical voltages and
currents.

Foreign refers to electrical voltages or currents that are
not normally carried by, or expected in, the
telecommunications distribution systems.
38
Safety

The results of such disturbances could be:
◦
◦
◦
◦
Death by injury.
Destruction of electronic equipment.
Down time.
Work and/or process degradation.
39
Level of Electrical Shock





Effects on the body are related to the duration and
power of the shock, and the resistance and position of
the body.
The body can feel 1 milliamp of current and the muscles
involuntarily contract with as little as 10-15 milliamps
100 to 200 milliamps (0.1 to 0.2 Amps) often fatal as it
clamps the heart
Over 200 milliamps causes physical injury
Low level currents can cause injuries or death from
involuntary muscle reflex reactions
40
Electrical Intrusion

Frayed electrical cords, loose
internal electrical connections or
intrusion into electrical cables or
systems may energize cases or
chassis.

Tools, chassis, racks, cabinets and
any other conductive structure
must be grounded.
41
Common Electrical Accidents

The most common electric shock occurs from
inadvertent, accidental contact with energized
devices or circuits.
 Cutting or drilling blindly into a wall
 Unprotected or exposed electrical system on a
construction site
◦ Panels, cables, outlets, switches, etc
◦ Faulty installation (exposed or unterminated live wires).
 Assuming a cable is not live
 Digging into an electrical cable
 Working too closely to overhead lines
42
Responsibilities

Unless you are a certified
electrician it is illegal for you to
perform any work on electrical
systems.
Establish a relationship with a trusted electrician
for those times when electrical work is required.
Report all electrical workplace hazards.
43
Lightning Protection
44
Lightning Protection Planning
Lightning is somewhat unpredictable. Careful planning
is required to protect people, buildings and equipment
from damage.
 Described in detail in ANSI/NFPA 780
 TIA/EIA requires a lightning protection system, but this
system is not the responsibility of the communications
system designer

45
Basic Lightning Protection



A zone of protection surrounds building
to intercept, divert, and dissipate strikes
A system of equalizing, air and ground
conductors make up the building
grounding system
A Cone of Protection is an area under a
nearby lightning protection system.
image: Public Domain
Cone of Protection
46
Lightning Protection Systems
Provide a designed path for lightning current
to travel
 Includes:

◦
◦
◦
◦

Air terminals (lightning rods)
Conductors
Ground terminations (ground rods)
Surge arresters and surge protectors
The telecommunications ground must be
bonded to the lightning protection system
within 3.7 meters of the base of the building
image: wiki
47
Buried Cable Planning

Susceptibility is determined in part by soil resistance
◦ buried cable collects ground strikes within an area determined
by soil resistance, typically 2-6 m (6-20 ft)
◦ high soil resistance intensifies this problem

Recommendation is to provide a grounding system for
all buried cable
48
Aerial Planning

Aerial cables often have power
cables above
◦ The power cable may intercept or
divert lightning strikes
◦ This helps, but does not eliminate
the need for protectors
49
Working Outdoors with Lightning
Lightning claims more lives in Canada than hail,
tornadoes, wind and rain combined.
 If working outdoors and a lightning storm is
approaching, seek shelter in a passenger vehicle or
protected building.
 Although there is a “Zone of Protection” under
lightning attractors, lightning may travel through the
ground and strike people.

◦ Avoid standing next to lightning attractors such as trees,
lighting and other tall objects
◦ Metal fences, rail tracks, cables and other structures can carry
strikes over large distances and into the “Zone of Protection”
http://www.ccohs.ca/oshanswers/safety_haz/lightning.html
50
Protection & Electrical Code

Lightning Exposure (Telecommunications)
◦ The CEC requires a listed primary protector (at both ends) whenever
outside plant cable may be exposed to lightning or electrical power
disturbances
Telus Residential Installation Document, including Network Interface
Devices (NID) (images: www.telus.com)
51
Building Entrance Protectors

Primary Protectors protect telecom facilities and
equipment from abnormally high voltages and current
◦ Located at the building entrance (indoor or outdoor)
◦ Protects against high voltages and currents

Secondary Protectors
◦ Located nearer to the equipment
◦ Add a second layer of protection that is more precise and
faster in its voltage protection
◦ Often includes other elements such as current protection and
filters
52
Two Categories of Communication Cable
Electrical Protection
Shield and other metallic cable elements:
1.
◦
◦
Bond directly to the closest available ground
Use approved bonding connectors
Conductive communication wires:
2.
◦
Employ building entrance protectors
53
Circuit Protectors

‘Primary protectors’ are most typically made
from carbon blocks, gas tubes, or solid state
◦ Installed immediately adjacent to the exposed cable’s
point of entrance
◦ Bond a grounding conductor directly to the
protector’s ground
54
Carbon Protection Modules





The earliest style available
An air gap between carbon elements
is adjusted to arc at about 300 volts
and send the current to a ground
conductor
Can short permanently
Limited lifespan
Still available, but they have been
replaced by gas and solid state
technologies
55
Gas Protection Modules
Provide a discharge gap between two
electrodes sealed in a ceramic
envelope containing inert gases
 Usually arc at a lower voltage than
carbon, providing better protection
 Have a much longer lifespan than
carbon

56
Solid State Protection Modules
Longest lifespan
 Solid state construction provides
nanosecond response time
 External failsafe mechanism which
permanently grounds the module under
sustained high current conditions
 More expensive but most reliable

57
Sneak Circuit Protectors

Sneak currents are unwanted currents that find their
way into a communication system

Secondary protectors are typically made from heat
coil, sneak-current fuse, or thermal resistors
Current Protection Module
image: www.siemon.com
58
Protectors Best Practices







Accessible for maintenance
Close to the power service entrance
Limit the length of conductors & keep straight
Ground the protector panel to nearest grounding
electrode system with #6 ground wire
Protect all conductors in the cable
Protect both ends of the cable
Leave space for additions
59
Grounding the Equipment
Grounding the equipment,
outside and inside. Images from the
National Association for Amateur Radio
image: www.arrl.org
60
3 Principles for Communications Grounding

Equalization
◦ minimize differences in ground potential
◦ use short, direct path with large conductor

Diversion
◦ bonding conductor is connected to the systems ground at both ends
◦ bonding conductors follow communications conductors and can easily
divert transients away from the communications conductor

Coupling
◦ the closer the bonding conductor is to the communications cable, the
greater the mutual coupling
61
Types of Grounds

A building may have six defined types of
grounding and bonding systems designed to
provide overall protection for the building and
its occupants:
◦
◦
◦
◦
◦
◦
Lightning protection system
Grounding electrode system
Electrical bonding and grounding system
Electrical power protection system
Telecommunications bonding and grounding system
Telecommunications circuit protector system
62
Building Grounding Electrode System

Established by the electricians. Consists of
◦ connection to earth ground
◦ conductor
◦ bonding points

Attached to the system are:
◦ Electrical Safety grounds
◦ Any metallic elements of the electrical installation including
tray, conduit, electrical boxes, panels, etc
◦ Cable shields and building entrance equipment

Lightning protection should be an independent ground
that never enters the building
63
Telecom Grounding Choices

Direct attachment to the closest point in the building’s electrical
service grounding electrode system.
◦ Preferred because telecommunications cabling and power cabling must be
effectively equalized

Select the nearest accessible location to:
◦ The building ground electrode system or,
◦ An accessible electrical service ground or,
◦ Gas Pipes

Cold water supply pipes are a poor choice today
 Plastic pipes are now commonly used
 In many jurisdictions connections to water pipes for safety grounding is no longer
permitted because of the increased use of nonmetallic pipe.
64
Attachment to the cable shield

Bonding connectors include “coins”, clips, clamps,
“beaver” bonds and other device
◦
◦
◦
◦
◦
Used with outside plant cables (some indoor)
Used is splices, building entrances
Sized based on the cable size (pair count)
Consist of: a base, a top, and nuts (may also include a shoe)
Have teeth to create a good electrical connection with the
shield of the cable.
image: www.3m.com
images: prgodin
65
Additional Bonding Products
Copper bond bar
- different lengths available
- holes and slots for attachment
 Bonding braid
 Insulator tubing
 Diaper wrap for encapsulating splices

66
The 607B Standard
67
The 607B Standard
ANSI TIA 607B covers grounding and bonding
for telecommunications
 Canadian Electrical Code

◦ published by CSA
◦ coordinated product test standards
◦ similar, but not identical to, the NEC
68
Grounding and Bonding

Standards from the following organizations are
the four main sources for information about
grounding and bonding codes and practices
◦ National Electrical Code (NEC)
◦ ANSI/TIA-607B: Commercial Building Grounding and
Bonding for Telecommunications
◦ Underwriters Laboratories UL-497: Protectors for
Paired Conductor Communication Circuits
◦ IEEE Standard 142-1991: Grounding of Industrial and
Commercial Power Systems
69
Protection System Planning
 Advantages
to planning early:
◦ better access to installation areas
◦ system components can be protected from
mechanical and environmental effects
◦ improved aesthetics
◦ it is generally more cost effective to meet
protection requirements during the initial
construction
70
Bidding and Contracts
even if the customer has not requested
protection equipment consider including it in
your bid if it does not already exist
 who is responsible for each protection system?
 every item in the protection system adds value
for your customer

◦ customers have a right to know what they are getting
71
The 607B Standard
Discusses a grounding system for the
telecommunications equipment
 Easy standard to understand
 Main elements of the standard:

◦ TBB (Telecom Bonding Backbone): A grounding
conductor that runs through the TR, ER and EF
◦ TGB (Telecom Grounding Backplane): Bonding plate in
each of the rooms
◦ TMGB (Telecom Main Grounding Backplane): A larger,
centralized bonding plate placed near the grounding electrode
system
◦ TEBC (Telecom Equipment Bonding Conductor): cable
assemblies that connect between the TGBs and the equipment
72
73
Building Grounding Electrode


An Electrician connects the system to the grounding electrode.
The Grounding Electrode is a direct, low-resistance connection
to the earth used as the electrical safety ground.
The Telecom Bonding Conductor (TBC) connects between the
Grounding Electrode and the TMGB
74
TMGB

Telecommunications Main Grounding Busbar
◦ Central connection point typically located in the EF
◦ Standard defines its construction (dimensions, copper
construction, hole sizes)
◦ May also be used for grounding building entrance
protection
image: www.homebrella.ca
75
TGB

Telecommunications Grounding Busbar
◦ Located in everay TR and ER
◦ Standard defines its construction (dimensions, copper
construction, hole sizes)
76
TBB
Telecom Bonding Backbone
 The TBBs originates at the TMGB
 Consist of:

◦ Stranded 6 AWG (minimum) copper conductor,
insulated with green jacket
◦ Routed with minimum bends or changes in direction.

Must not be cut (use a tap connection)
Tap Connection
77
http://www.electrical-contractor.net/forums
http://www.panduit.com
Example of compression/crimp connectors for attaching to the TBB
78
TBB Planning

When planning TBB installation:
◦ Be consistent with the design of the
telecommunications backbone cabling system
◦ Use multiple TBBs if the building size permits it, but
they must be bonded together at the top floor
◦ Bonding conductors between a TBB and TGB must be
continuous and routed as directly as possible
◦ Visibly labeled and physically secure
79
TBB/TGB Connection
The TBB is connected to the equipment with a BCT
(Bonding Conductor for Telecom)
 The connections should be compression (crimp or
screw terminal)

Example of acceptable connectors at the TGB and equipment
images from www.panduit.com
80
81
TIA/EIA 607B - Overview 1
A permanent infrastructure for
telecommunications grounding and bonding,
independent of the telecommunications cabling
 Minimum 6 AWG (large as 3/0 AWG) insulated
bonding conductors are installed through every
major telecommunications pathway (TBB)
 TBBs are directly bonded to a
telecommunications grounding busbars.

82
TIA/EIA 607B - Overview 2
TMGB are directly bonded to the electrical
service ground
 All TBBs end on the TMGB
 Each TBB should be a continuous conductor
from the TMGB to the farthest TGB
 Intermediate TGB should be spliced to the TBB
with a short bonding conductor

83
TIA/EIA 607B - Overview 3
Each TGB is also directly bonded to building
structural steel and other permanent metallic
systems, if close and accessible
 Each TBB that reaches a TGB location must be
bonded to the TGB

84
TIA/EIA 607B - Overview 4
TGB and TBB must be visibly labeled and
physically secure
 All of the grounding busbars are used by
telecommunications systems installers for their
grounding requirements

85
TR

Telecommunications Rooms
◦ In a telecommunications closet, suitable ground
options include:
 Building structural steel.
 An electrical receptacle box or approved conduit
connection.
 A combination of these that is accessible.
 An already established communications ground.
86
Backbone Cable Protection

Cables that are inside a building are not usually
considered exposed, but protective measures
are occasionally advised
◦ High-rise and low-wide buildings and buildings close to
substations or heavy industrial facilities

Electrical power cable should be physically
separated from communications cables
87
Backbone Cable Protection
communications cables should be routed near
the center of the building
 a lightning protection system is advised
 exposed cables entering the building should be
protected and grounded
 bonding should be installed along each backbone
cable pathway

88
Inspection

Visual inspection can usually reveal problems,
such as:
◦
◦
◦
◦
Loose connections.
Corrosion.
Physical damage.
System modifications.
 Note: During any service work, the installer should visually
inspect bonding connections.
89
Review
90
Summary
All telecommunications systems require
grounding and bonding systems.
 Several associations provide codes, standards,
and minimum requirements for installing these
systems. ANSI/TIA-607, “Commercial Building
Grounding and Bonding Requirements for
Telecommunications,” is the primary source of
installation information.
 Another important source is the NEC

91
Summary

Grounding and Bonding
◦ Provide additional safety factors where equipment
and people are involved.
 It protects people from being shocked by voltage potentials.
 It provides a point of discharge for static electricity.
 It reduces or eliminates stray voltage and current.
◦ Reduce the effects of lightning, static electricity and
ground faults
◦ Properly grounding the shields of cables can help
reduce noise and crosstalk from adjacent cables.
92
Summary
A grounding and bonding network is made up of
insulated copper conductors. These conductors
are run in parallel with the telecommunications
cables, and link rooms containing
telecommunications equipment to a common
ground.
 The recommended size for these conductors
range from No. 6 to No. 3 /0 AWG insulated
copper

93
Summary

These conductors are bonded to solid copper
grounding busbars, which are installed in the
entrance facility, the main telecommunications
room, and all other telecommunications rooms.
In addition to the conductors that run
throughout the building, telecommunications
equipment, frames, cabinets, raceways, and
protectors are grounded to the busbars
94
Summary

The busbars throughout the building are bonded
together with a backbone cable of at least No. 6
AWG insulated copper. This backbone cable is
also connected to the main grounding busbar,
which is bonded to the electrical service
(power) ground and an earth ground
95
Summary

Telecommunications circuit protectors are used to
protect telecommunications facilities and equipment
from abnormally high voltages and currents. This
protection is in addition to the requirements and
recommendations for grounding and bonding
telecommunications systems

Documentation makes your job easier and helps you
and your networks work more efficiently
END
prgodin @ gmail.com
96