NI02
Telecommunications
Bonding and Grounding - Industrial
PANDUIT Physical InfrastructureSM Solutions
Grounding & Bonding Systems
John French
Technical System Engineer
jrf@panduit.com
SM
Let’s Review Some Fundamentals….
1. True/False: Electricity
always follow the path of
least resistance.
A: This is FALSE. Electricity FAVORS
the path of least resistance, but it
follows all paths available to it.
2. True/False: Electricity wants
to return to the Earth
A: This is FALSE. Electricity always
wants to return to it source. Only
Lightening returns to Earth.
Design is Critical
A properly designed grounding and bonding system is:
– Intentional,
– Visually verifiable,
– and Adequately Sized
…to handle expected currents safely and without undue effect
on susceptible electronic equipment.
What are the effects of Improper Grounding?
Lower Reliability
• An improperly designed grounding (and bonding) system may be a
primary source of interference and emission.
• According to the IEEE, the typical AC third-prong ground circuit is almost
never sufficient to prevent damage to network equipment susceptible to
ground-fault related potentials.
• Poorly designed or improperly applied grounding, bonding, and shielding
techniques often adversely affect the performance of electronic
equipment – from the circuit board to the network system.
• Approximately 70% of all anomalies, dysfunctions, or problems associated
with power distribution systems are directly or indirectly related to
bonding and grounding issues.
What are the effects of Improper Grounding?
Safety Risks
• Personal injury from electric shock caused by improper grounding and
bonding can cause immeasurable human suffering and significant
expense.
• Potential fire hazards exist when heat is generated from electrical surges
that occur on a high impedance grounding and bonding path.
“Device to Dirt”
• The mistake most often made in any Network or Industrial grounding
system is to not look past the closest connection when providing
grounding for equipment being installed.
• You see a ground point and make an assumption that the connection is a
proper ground and that all connections leading from it go to the right
place.
• When is reality, this is very often not the case….
Let’s look at this example:
There are three types of grounds
referenced in electronics
•
•
•
•
Chassis Ground: generally refers to using the chassis or frame of a device as a
common return path and reference point for a circuit or circuits mounted on and
electrically connected to that chassis or frame.
Signal Ground: A return path for signals and power within a circuit and/or a
connection between separate circuits and/or circuit boards. Also called “Circuit
Ground” or “Circuit Common”
Earth Ground: refers to a common return path with a direct physical connection to
the Earth. Also called “Earth Return” and is done for safety purposes to protect
people from the effects of faulty insulation.
NOTE: The schematic symbol for Earth Ground is often used as a generic ground symbol. Though this is
probably not a good practice.
That’s pretty straight forward, Right?
Just what does the term Ground indicate?
• Ground wire terminated to case?
• Case terminated to ground on electrical
outlet?
• Outlet ground tied to junction or power
panel?
• Neutral tied to ground at junction box?
• Junction box tied to service entrance?
• Ground lead tied to structure steel?
• Ground tied to copper water pipe
• Ground tied to ground rod?
How can we say the word
“Ground” and mean so
many different things?
Here’s another example: What’s the difference
between a Common Ground and an Earth Ground?
• A Common Ground is the point
where many Equipment
Grounds join together to be
grounded to the ground with an
Earth Ground!?!
• Does that sound silly to you?
• Confused?
Do you see any overlap in
the symbols being used?
SM
Why is there such confusion?
• For years the NEC Code interchangeably used the terms:
– Bonding, Grounding and Earthing.
• Many countries outside the U.S. actually use the term
Earthing to mean Grounding.
• And almost no one uses the term Bonding for anything!
Understanding Grounding Systems
To have a good conversation about Grounding Systems we need
to establish a vocabulary to use to describe different areas of the
system.
We need to learn 3 terms:
• Earthing
• Grounding
• Bonding
Understanding Grounding Systems
Earthing
Earthing - Earth or a conductive body
that is connected to earth.
SM
Understanding Grounding Systems
Earthing
Grounding
Grounding – The point at which all
“Bonded” conductors come together at
“Earth”.
SM
Understanding Grounding Systems
Earthing
Grounding
Bonding
Bonding – Every other “ground” like
connection inside the facility
SM
Understanding Grounding Systems
Understanding these three things will alleviate MOST
grounding issues within any facility.
Earthing
Grounding
Bonding
Grounding and Bonding Infrastructure
Grounding Electrode System
• Electrode Types
• Connection Types
Grounding and Bonding Infrastructure
Telecommunications Grounding and Bonding Infrastructure
Standard Requirements
• TIA-607-B (revised J-STD-607-A )
• NECA /BICSI-607-2011 (New)
www.global.ihs.com
Grounding and Bonding Systems
Equipment Room’s with Access Floors
Standard Requirements
• TIA-607-B
• NECA /BICSI-607-2011
Grounding and Bonding Systems
Equipment Room’s with a Slab Floor
Standard Requirements
• TIA-607-B
• NECA /BICSI-607-2011
Grounding and Bonding Systems
Industrial Automation Applications
Grounding and Bonding Systems
Techniques for Control Panel Building
Control Panel
Solutions
Defining grounding and bonding
NFPA 70-2011 (National Electrical Code, a.k.a. “NEC”)
• Grounded (Grounding). Connected (connecting) to ground or to a conductive
body that extends the ground connection.
• Bonded (Bonding). Connected to establish electrical continuity and conductivity.
Grounding and Bonding 101
What is Grounding and Bonding?
A Grounding & Bonding System
is most often associated with
the protection of personnel, equipment and
property from electrical disturbances caused by
lightning, Electrostatic Discharge (ESD), surge
or fault currents and transient voltages.
Grounding and Bonding 101
What Does Grounding Do?
• Provides a reference to earth to stabilize the system
voltage for the Power Distribution System.
• Provide paths for fault current to get back to its source
without damaging equipment and facilitate operation of
over current devices (breakers and fuses).
• Promote equalization of electric potentials (voltages)
between equipment, earth and personnel by bonding
conductive paths together
– Lightning
– Electrostatic discharge
Grounding and Bonding 101
The Risks of Improper Grounding & Bonding
Safety
Shocks
Fire hazards
Lightning
Insurance data: $500 million/year due to lightning damage
Equipment failure
Industry experts estimate 27-33% of damaged equipment due to
ESD (Electrostatic Discharge)
The risk of electrical noise
The performance of shielded data cable requires proper bonding &
grounding.
Grounding and Bonding 101
Lightning
Lightning bolts can generate voltages in excess of 100M V
Lightning is lethal of up to 60 ft or 600 ft in water from point of contact
Lightning does not need a direct strike to induce electrical surges
Transients can affect both overhead and buried cables
Lightning can generate surges onto facilities of:
70 Volts at a distance of 1 mile (1.6km) 10K Volts at of 500 ft
(150m)
Grounding and Bonding 101
Electrostatic Discharge
Electrostatic charges are generated when different materials come into
contact and are then separated.”
Cables can acquire a charge during installation when they are unreeled
from a cable reel, or dragged across a floor. There are reports of cables
developing charge from moving air
If you see or hear the ESD discharge it is a minimum of 2900V
Here are some examples of voltages generated by ESD events:
Walking across carpet:
1500 - 35,500 volts
Picking up a plastic bag:
1200 – 20,000 volts
Crossing your legs:
300 volts
ESD Is greatly affected by Relative Humidity
Grounding and Bonding 101
ESD Protection
Manufacturers ESD resistance is designed to work under normal
operational scenarios
All built-in ESD protection is worthless when the product is opened –
must use external ESD protection
Exposed printed circuit boards are most susceptible, like the ones
found on plug-in cards or blades
Grounding and Bonding 101
Cisco on Grounding
From the Catalyst 6500 Series Switch Installation
Guide:
“When you properly ground systems during installations,
you reduce or prevent shock hazards, equipment damage
due to transients and data corruption.”
“Always use an ESD wrist strap…”.
Use a 6 awg wire for the chassis ground.
“Prepare the other end of the grounding wire, and connect
it to an appropriate grounding point in your site to ensure
adequate earth ground for the switch.”
Grounding and Bonding 101
What is required by “Code” for
Grounding and Bonding in an IT Equipment Room?
“the code says”
Per the NEC Article 645.15: “All exposed non-current
carrying metal parts of an information technology system
shall be grounded in accordance with Article 250 or shall be
double insulated”.
“we interpret non-current carrying metal as”
What are the non-current carrying metal parts?
Racks, Cabinets, Zone Enclosures
Metallic Cable Pathways: Ladder racks, Wire Baskets, Cable Trays
Access Floor Structures
Under-floor: conduits, dividers, water pipes
Grounding and Bonding Infrastructure
The Grounding Electrode System
TelComm
To Building
Grounding
Electrode System
2
1
5
3
4
6
SM
The following grounding electrodes that are present MUST
be bonded together to form the electrode system:
1. Metal underground water pipe
2. Metal frame of building or structure
3. Concrete-encased electrode (Ufer)
4. Ground Ring
5. Rod or pipe electrode
6. Plate electrode
NEC Code Section 250.50
Grounding & Bonding Infrastructure
The Grounding Electrode System – Structural Steel
At least one structural metal member
must be in direct contact with earth
for 10 ft or more, with or without
concrete encasement.
Or
Hold down bolts holding structural
steel most be bonding to a concrete
encased electrode in the support
footing or foundation.
Grounding & Bonding Infrastructure
The Grounding Electrode System – Concrete Encased Electrodes
Shall consist of at least 20 ft of either
• Steel reinforcing bar (REBAR)
Or
• Bare copper conductor of 4 AWG
minimum.
Grounding & Bonding Infrastructure
The Grounding Electrode System –
Rings, Rods, Pipes and Plates
Ground Rings
Minimum of a 20 ft, 2 AWG in direct contact with the earth
Buried not less than 30 in.
Ground Rods and Pipe Electrodes
Both shall not be less than 8 ft.
Pipe or conduit no smaller than 3/4” diameter and the outer surface galvanized
Rod’s of stainless steel, copper or zinc coated steel shall be no smaller than 3/8”
diameter
Plate Electrodes
Make at least 2 ft² surface contact with soil.
Bare or uncoated iron or steel plates a minimum of ¼” thickness
Do not use Gas Pipes or Aluminum for grounding electrodes
Grounding & Bonding Infrastructure
The Grounding Electrode System –
Connection to the Grounding Electrodes
Article 250.70 Methods of Grounding and Bonding Conductor
Connection to Electrodes.
“The grounding or bonding conductor shall be connected to
the grounding electrode by exothermic welding, listed lugs,
listed pressure connectors, listed clamps, or other listed
means. “
Types of Connectors allowed by Code and Standards
Mechanical Connections
Compression
Exothermic Welding
Grounding & Bonding Infrastructure
The Grounding Electrode System
Mechanical Connectors
Typically used in residential.
Can be removed or tampered with
Prone to corrosion
Requires maintenance
Inexpensive
Installs easier than compression and exothermic welding.
Grounding & Bonding Infrastructure
The Grounding Electrode System
Exothermic Welding
•
•
•
Typically used in commercial, industrial and Utility
Produces a dangerous chemical reaction that heats to 4200F to make bond. Can cause
serious burns and cause fires. Personal protective equipment and fire extinguishing
equipment is required for installation.
Storage of flammable materials required. Hazardous materials permits may be required
in certain installations.
Grounding & Bonding Infrastructure
The Grounding Electrode System
Exothermic Welding
• Hundreds of combinations of molds and shots. Installation is more complex
than both mechanical and compression connectors.
• High failure rate / rework
• Irreversible Connection
• Excellent Corrosion Resistance
• Inspection process is unreliable
Grounding & Bonding Infrastructure
The Grounding Electrode System
Compression Connectors
Typically used in commercial, industrial and utility.
Irreversible
Excellent corrosion resistance – tested to IEEE 837-2002 standards
Installs easier and faster than exothermic welding.
Less tools required; one crimp tool and (3) dies
Can be easily inspected for proper installation
crimp process
embosses die
index number
on part
IEEE Std 837™– 2002: Industry’s highest
grounding connector performance specification
• Purpose of 837: “guarantee that the
connection will perform satisfactorily
over the lifetime of the installation”
• The 2002 version of IEEE Std 837 is
significantly more stringent than the
1989 version
• The 2002 test requires the resistance
after lifestyle aging tests to vary by a
factor of less than 50%, whereas the
1989 version allows resistance changes
of up to 150%
SM
Why did IEEE revise the 837 standard in 2002?
• Official reason was to clarify testing requirements
• Reports from the field showed that buried connectors were sometimes
degraded significantly
• High levels of corrosion reported between connector and conductor
• Grounding system failure results from this corrosion
• When IEEE revised the test, the new acceptance criteria used ensures that
connectors will better withstand the direct burial environment
• The best measure of how degraded a connection has become is the
resistance through that connection
• Higher resistances at the end of the test sequence with respect to the
resistances when the connections are first made are indicative of
connection degradation
STRUCTUREDGROUND™
Direct Burial Compression Grounding
The Grounding Electrode System and Entrance Facility
TMGB
Conductor to
ground rod
Conductor to
grounding
electrodes
Conductor to
building steel
Conductor to
conductor
12 connectors & 3 crimp dies meet all your grounding needs
Conductor to
rebar
Compression connectors are capable
of more current than the conductor
connector
conductor
Compression vs Exothermic Welding Process
• Safety issues for installer minimized
• No hazmat or hot work permits
• No delays due to weather (precipitation and
wind)
• No forest fire danger.
• Meets IEEE 837-2002
• 3 minute install vs. 7-15 minutes for
exothermic per connector.
• Inspection is simple, reliable and tested.
• Fewer tools and supplies required
• No Need to store flammable products
Compression works in extreme cold (e.g. -40o in northern
Alberta’s oil sands)
Grounding & Bonding Infrastructure
The Critical Connections
Industrial/Commercial Buildings
The application usually determines the
performance level required and guides the
design of the grounding electrode system.
Substations
Communication Sites
Factors that will affect the design:
• soil resistivity
• temperature
• moisture
• minerals and salts in soil
Rail Roads
Wind Farms
Standards Change
Telecommunications Bonding Backbone
(TBB) Sizing
J-STD-607-A (old)
TIA-607-B (new)
Design specifications, per TIA-607-B-1
• Commission a soil resistivity study
The most common method of measuring average soil resistivity is the
four-point method
Require a series of readings in different locations to get a better idea of
the soil conditions
SM
TIA-607-B-1 potential equalization design highlights
SM
Grounding and Bonding Systems
Telecommunications G & B
Infrastructure Products
Ground Bus Bars
2-hole Compression
Connectors
Full line of connectors for the
Telecommunications and Electrical
Grounding Infrastructure
Copper Compression
Taps and Covers
Beam Clamps
56
Preventing loose busbar connections
Two-hole
compression
lugs
Telecommunications
Grounding Busbar (TGB),
BICSI/TIA-607 hole
pattern
(Type LCC-W)
(Type GB2B, or Part GB2B0306TPI-1)
BICSI-607 stainless steel
TGB hardware stack-up
(Parts HDW1/4-KT, HDW3/8-KT)
PANDUIT
Tools
Products
Technical Support
Installation Tooling
HTAP Crimping
• HTCT HTAPs require 12
tons of compression
• CT-2930/L is
recommended
• Can use other
manufacturers’ tools
and retain UL
Listing/CSA Certification
• Must use Panduit
locator dies
Patented
locating rib
guarantees fullwidth crimp 1st
time, every
time!
CT-2930/L
HTCT HTAP
CD-930H-250 Locator Die
Do you already own the tools?
• Panduit lugs can be crimped with select competitors’ tools
and dies and still retain UL/CSA approvals
• HTAP and direct burial GCE and GCC products can be
crimped with competitors’ tools, but require Panduit dies and
still retain UL/CSA approvals
Grounding and Bonding Systems
Installation Tooling
Grounding and Bonding Systems
Depth of Product Lines
Terminals
Power Connectors
Data Center Kits
Mechanical Grounding
Compression Taps
Direct Burial
CTAPF
HTAP
CTAP
Grounding and Bonding Systems
Knowledge and Solutions
for Multiple Applications
Telecom Room
Data Center
Telecommunications
G&B Infrastructure
Grounding Electrode System
Entrance Facility
Control Panels
Grounding and Bonding Systems
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Questions?
John French
Technical System Engineer
jrf@Panduit.com
Thank You!