DC200B Chapter ?

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OBJECTIVES
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Understand all components that comprise the entrance facility.
Determine the location of the entrance facility.
Identify the demarcation point.
Understand the different methods used to bring outside plant cable into
a building or structure.
Understand the difference between grounding and bonding.
Identify grounding system components.
Understand ground loops
Understand retrofitting installation considerations.
Determine and understand the need for firestopping.
Understand the testing for firestop systems.
Identify system solutions for firestop applications and inspecting
installations.
Identify major codes that require firestopping.
Define the term Ground and describe different types of grounds.
List the characteristics of a proper telecommunications closet.
Figure 3-1: Entrance Facility
Figure 3-2: The Demarcation Point
The UL Cable Certification Program offers
five levels of performance:
Level I - cable performance intended for use as
basic communications and power-limited circuit
cable. There are no performance requirements
for cable at this level.
Level II - cable performance that is similar to
that for Type 3 cable (multipair communications
cable) of the IBM Cabling System Technical
Interface Specification GA27-3773-1. These
requirements apply to cables with between two
and 25 twisted-pair conductors that are either
shielded or unshielded.
The UL Cable Certification Program offers
five levels of performance: (continued)
Level III - cable performance that complies
with the TIA/EIA wiring standards for
horizontal unshielded twisted pair cable.
These requirements are set forth in the
TIA/EIA Technical Bulletin PN-2841. These
requirements apply for both shielded and
unshielded type cables.
The UL Cable Certification Program offers
five levels of performance: (continued)
Level IV - cable performance that complies
with the requirements in the NEMA’s
(National Manufacturers Association)
standard for low-loss premise
telecommunications cable. Level IV
requirements are similar to the TIA/EIA
standards set forth for Category 4 cabling.
These requirements apply for both shielded
and unshielded type cables.
The UL Cable Certification Program offers
five levels of performance: (continued)
Level V - cable performance that complies
with the requirements in the NEMA’s
(National Manufacturers Association)
standard for low-loss premise
telecommunications cable. Level V
requirements are similar to the TIA/EIA
standards set forth for Category 5 cabling.
These requirements apply for both shielded
and unshielded type cable constructions.
The location of the entrance facility is determined
by several key factors. These are:
The location of the local service provider’s
lines
How the service lines must enter
the building
The location of the telecommunication
closet
There are three primary methods by which
an outside plant cable may enter a premise:
Aerial cable
Buried cable
Underground cable
Figure 3-3: Outside Plant Cable Entry Methods
Figure 3-4: Buried Cable
Some advantages of buried cable applications
are:
They preserve the appearance of
the premise.
They can be easily routed around
any obstructions.
They offer an inexpensive initial
installation cost.
The following list contains general requirements
for conduit-carrying underground cables to an
entrance facility:
There should be at least one 4-inch (inside
diameter) conduit, plus one spare conduit for
future expansion. Most sections may be made
of Type C PVC conduit.
Entrance conduit should be galvanized steel
through the foundation wall to a point 12 inches
beyond the disturbed earth.
The following list contains general requirements
for conduit carrying underground cables to an
entrance facility: (continued)
Bends in underground conduit should be avoided.
If circumstances warrant them, however, a
maximum of two 90-degree bends are allowed.
The bends should be made of galvanized steel
encased in four inches of concrete.
Conduit that parallels other utility conduits should
maintain a minimum distance of 12 inches. This
distance may be reduced to 4 inches if the entrance
conduit is encased in four inches of concrete.
The following list contains general requirements
for conduit carrying underground cables to an
entrance facility: (continued)
When possible, conduit should be buried at a
depth of 48 inches. A shallower depth, but not less
than 24 inches, is allowed to avoid obstructions.
Conduit entering through a basement or
foundation wall should be sloped away so that
water cannot run into the building.
The advantages of underground conduit
entrance facilities are:
They preserve the appearance of
the premise.
The cables are easily maintained
or replaced.
The conduit provides a protective
barrier from external elements
such as weather or rodents.
Figure 3-5: Typical TC/ER Layout
Table 3-1: TC vs. Serving Area Floor Space
Table 3-2: ER/EF Wall Length vs. Serving Floor Space
Table 3-3: ER/EF Dimensions vs. Serving Floor Space
Figure 3-6: Common Ground Potential
What should be grounded?
1
All outside-plant copper backbone cables must
have their metallic cable shields bonded to the
ground lug of the primary protector block at
the entrance of each building.
2
Any outside-plant fiber optic cables that contain
metallic shielding, or metallic strength members,
must have those metallic components bonded to
the telecommunications main grounding busbar
(TMGB) at each end of the cable.
3
Any inside-plant copper or fiber optic backbone
cables that contain metallic shielding must have
their shields bonded to the TMGB at each end.
What should be grounded? (continued)
4
Where any splices are made to backbone
cables, the metallic shields of those cables must
be bonded together to maintain shield
continuity.
There are various methods used to bond metal
surfaces. These include soldering, brazing,
welding, clamping, sweating, high-strength
bolting, or any combination of these.
Soldering – an activity that unites metallic
surfaces using a soft metal or soft metallic alloy.
Brazing - a soldering activity that uses a
nonferrous alloy having a lower melting point
than the metals being joined. Applying solder
to strengthen the ends of copper conductors
before bolting them to the grounding frame is a
common example of brazing.
There are various methods used to bond metal
surfaces. These include soldering, brazing,
welding, clamping, sweating, high-strength
bolting, or any combination of these. (continued)
Sweating - the practice of heating metal surfaces
to allow solder to melt between their surfaces to
unite them. The heat-producing flame or
soldering iron does not come into contact with
the solder, but rather is used to heat the surface
of the joining metals.
There are various methods used to bond metal
surfaces. These include soldering, brazing,
welding, clamping, sweating, high-strength
bolting, or any combination of these. (continued)
Welding - an activity that unites metals by
melting them so that their surfaces flow together
to form the bond.
Clamping - is a mechanical connection that
provides a path between conductors. This type
of connection should be avoided and should
only be used in temporary equipment where a
quick disconnect type of connection is
required.
There are various methods used to bond metal
surfaces. These include soldering, brazing,
welding, clamping, sweating, high-strength
bolting, or any combination of these. (continued)
High strength bolting - an activity where
mechanical connections are made with highstrength structural bolts.
Figure 3-7: Earth Grounding
Figure 3-8: Equipment Grounding
WARNING
ALL PRECAUTIONS SHOULD BE
TAKEN TO PREVENT CONTACT OF
THE SKIN WITH THE SOLVENT AND
TO AVOID BREATHING THE
VAPORS.
The components of a typical telecommunications
grounding system:
Telecommunications main grounding busbar
(TMGB)
Telecommunications grounding busbar (TGB)
Telecommunications bonding backbone (TBB)
Telecommunications equipment bonding
Conductor (TEBC)
Bonding conductor
Metal bonding straps
Protector panel
Grounding electrode
Figure 3-9: Typical Telecommunications Grounding
System Components
TIA/EIA 607 specifies the requirements for:
A ground reference for telecommunications
systems within the telecommunications
entrance facility, the telecommunications
closet, and equipment room
Bonding and connecting pathways, cable
shields, conductors, and hardware at
telecommunications closets, equipment rooms,
and entrance facilities
Figure 3-10: Main Distribution Closet
The connection of the TMGB to the
building’s main electrical service
grounding electrode must be performed
by a certified electrical professional.
Figure 3-11: Telecommunications Equipment Bonding
Conductor
However, when installing cable ladder racks or
trays, each section must be bonded together.
This can be accomplished in one of three ways
1
Remove any paint (down to bare metal) at the
point where the rack section interconnection
hardware is mounted. Bond the rack assembly
to the TMGB with a #6 AWG ground wire.
2
Bond all rack sections together using braided
metal bonding straps, or a #6 AWG ground wire.
3
Bond all rack sections to a #6 AWG ground cable
run throughout the entire length of the rack or
tray. The ground cable must then be bonded to
the TMGB.
Figure 3-12: Bonding Straps
Figure 3-13: Primary Protector Block
Figure 3-14: Shielded Twisted Pair Cable
Figure 3-15: Ground Loops
Figure 3-16: Current Cable Runs
The process of tracing current cable runs
actually involves several activities:
Make sure you check cable records.
Check labels on cables.
Check the labels on equipment being used.
Find out what cables are being used in
conjunction with the equipment.
Next, make sure that you check the crossconnect
archives:
Verify all lines at the point of termination.
Make a record of which jumpers are
connected to which termination points.
Use a recommended tone generator (or
tone tool) to trace the run to make sure
that neither end of the run is connected.
Also, confirm the runs on the documents
provided:
Check the blueprint for accuracy.
Confirm backbone labeling, if any, for
routing and labeling at termination points.
Verify that the equipment rack wiring
configurations are correct.
Finally, test the current physical connection
media:
When you are using required testing equipment,
substantiate the parameters of the existing
horizontal physical connection’s media.
Record test results.
Test and record copper backbone cables.
Use the power meter/light source to test fiber
backbone cable and record its readings.
Figure 3-17: Testing the Current Physical Connection
Media
Figure 3-18: Example of Structured Cabling System
There are five major steps that you must follow
before, during, and after installation:
1
Plan the topology.
Determine the planned use of systems.
Confirm whether the customer is planning
the use of a data system. What will it be?
Will it be a combination of systems?
Will a new voice system be installed, or will
the current system remain?
How many wire pairs does the voice system
require?
Reuse any physical connection media, if
possible.
There are five major steps that you must follow
before, during, and after installation: (continued)
2
Plan the backbone cabling.
Determine whether a fiber backbone is
required. If so, how many strands are
required?
Are both multimode and single-mode fiber
required?
Establish whether there is a need for a
copper backbone cable. If so, what paircount and category are required?
Figure 3-19: Plan the Backbone Cabling
There are five major steps that you must follow
before, during, and after installation: (continued)
3
Establish code compliance and standards.
Determine the physical borders of the
installation.
Is CMR-rated or CMP-rated cable to be
used?
Will firewalls be abtrused? If so, which
firestop materials are permitted by local
authorities?
Verify the need for dismissal of existing
cable from conduits and pathways before
installation.
There are five major steps that you must follow
before, during, and after installation: (continued)
3
Establish code compliance and standards.
Confirm the status, if any, of asbestos within
the facility. If asbestos is present, has it been
removed? If not, what planning is required?
Verify that the system layout complies with
ANSI/TIA/EIA 568A distance limitations for
both horizontal and backbone cables.
Confirm that the grounding system is
designed per ANSI/TIA/EIA 607.
Figure 3-20: ANSI/TIA/EIA 568A Distance
Limitations
There are five major steps that you must follow
before, during, and after installation: (continued)
4
Coordinate with other trade groups.
a. Electrical contractor
Will conduit be provided with pull string for work area
outlet locations or will new outlets be required?
Determine whether the electric contractor will install the
cable tray system, if any, outside of the
telecommunications closets (TC).
Confirm size, location, and installation of the grounding
conductor to the TMGB by the electrical contractor.
There are five major steps that you must follow
before, during, and after installation: (continued)
4
Coordinate with other trade groups.
b. HVAC (Heating, Ventilation, Air Conditioning)
Coordinate proposed cable paths with the HVAC
contractor to ensure no conflicts exist with ductwork,
access panels, fan coil units, etc.
Review mechanical, electrical, and plumbing plans, if
provided, so as to plan routing of horizontal cables.
c. Ceiling/Drywall/Painting contractors
Confirm timeframe for ceiling grid installation and dropin tile placement to ensure agreement with timeframe
planned for cable placement.
Coordinate workstation termination with drywall and
painting contractor to ensure no conflict exists.
There are five major steps that you must follow
before, during, and after installation: (continued)
4
Coordinate with other trade groups.
d. Furniture contractor
Determine the planned timeframe for any modular
furniture installation.
Verify furniture installation procedures. Will cabling be
installed through utility poles or fed from floor mount
boxes?
Establish what the connecting hardware should be,
based on the make and model of the modular furniture.
Does the system provide adequate space to maintain
bend radius requirements, or will surface boxes be
required?
Find out who is responsible for the final installation of
furniture base plates.
There are five major steps that you must follow
before, during, and after installation: (continued)
5
Plan the cutover.
a. Establish the method of implementation.
Confirm whether work will be done after or during
normal business hours.
Verify who is responsible for the interconnection of voice
and data systems to the new physical connection media.
Will the system be cutover under a flash cut scenario, or
will it be phased in over a period of time in preplanned
stages?
Does the customer need on-site support both during and
after the cutover?
Based on the size and scope of the project, will there be any
scheduled construction meetings for trade coordination?
There are five major steps that you must follow
before, during, and after installation: (continued)
5
Plan the cutover.
b. Testing
Perform all appropriate copper testing for all new cables
using either link or channel tests, as determined by the
customer, to meet TIA/EIA TSB 67 specifications.
Perform fiber testing, using either a power meter/light
source or an OTDR, as specified by the customer.
Figure 3-21: Copper Testing
There are five major steps that you must follow
before, during, and after installation: (continued)
5
Plan the cutover.
c. Documentation
Label all cabling as authorized according to
ANSI/TIA/EIA 606.
Enhance blueprints for the “as-built” document.
Supply interconnection drawings.
Make sure you supply rack layout drawings.
Produce all test results in both hard copy and
electronic media.
There are five major steps that you must follow
before, during, and after installation: (continued)
5
Plan the cutover.
e. Remove the cable support hardware.
Distract all tie wraps from cables to be removed.
Disconnect all fasteners from cable bundles to be taken
out.
Make sure you remove all cable terminations.
Disconnect all cables from work area outlets being
taken out.
Remove all terminations in the telco closet.
f. Remove the cabling.
Carefully salvage cables for disposal.
Properly eliminate cable.
Figure 3-22: Fire-Rated Barriers
Figure 3-23: Caulk and Putty Application
The following list provides some practical
points to consider when you are performing a
cable installation that requires firestopping:
Contact the local building inspector and fire
marshal to make certain you are familiar with
the current code regulations.
Check your company’s standard policies for
procedures related to installing firestopping
materials. If no policy or procedures exist, one
should be created.
The following list provides some practical
points to consider when you are performing a
cable installation that requires firestopping:
(continued)
Review the instructions supplied by the
intumescent material’s manufacturer.
Check to make sure all of the materials involved
in the installation are approved by a legitimate,
recognized testing organization (such as
Underwriters Laboratories, Inc.).
The following list provides some practical
points to consider when you are performing a
cable installation that requires firestopping:
(continued)
Use the following recommendations when
performing the actual installation:
Drill oversized holes for the installation so that the cable or
conduit fits easily through the penetration. However, do not make
the opening so large that it impacts the manufacturer’s minimum
depth thickness specification for the caulk or putty.
Never substitute nonfire-rated packing (such as regular
insulation) for fire-rated materials (such as wool bat).
Never reuse an existing firestop that does not meet code.
This may make you liable for the complete installation.
The following list provides some practical
points to consider when you are performing a
cable installation that requires firestopping:
(continued)
Use the following recommendations when
performing the actual installation:
Protect yourself by documenting your installation. This can be
done with an inexpensive camera. Simply record the important
information about the installation on the wall beside the
penetration. Then, take a photograph of it for your files. If
anyone violates the fire code at a later date, or an actual fire
occurs, you have the photograph as evidence of your work.
Some of the major codes requiring firestopping
arrangements are:
National Building Code - Building Officials and
Code Administrators (BOCA), which provides
a standard of construction regulations and
supports the enforcement of these regulations.
Standard Building Code - Southern Building
Code Congress International (SBCCI), which
provides the same standards of construction
regulations as the BOCA but is used mainly in
the southern part of the United States.
Some of the major codes requiring firestopping
arrangements are: (continued)
Uniform Building Code - International
Conference of Building Officials (ICBO) is a
building code used mainly in the western part
of the United States.
International Building Code - International Code
Council (ICC) is made up of representatives from
the BOCA, ICBO, and SBCCI. This council’s
purpose is to combine the codes of the three
model building code organizations to make a
single national model building code for use
mostly in the United States.
Some of the major codes requiring firestopping
arrangements are: (continued)
Fire Prevention Code (NFPA 1) - Provides basic
fire prevention requirements necessary to
establish a reasonable level of fire safety and
property protection from the hazards produced
by fire and explosion.
National Fuel Gas Code (NFPA 54) - Provides
the safety requirements for fuel gas equipment
installations, piping, and venting.
National Fire Alarm Code (NFPA 72) - Sets
minimum standards for fire alarm systems.
Some of the major codes requiring firestopping
arrangements are: (continued)
Life Safety Code (NFPA 101) - Provides for
minimum building design, construction,
operation, and maintenance required to protect
building occupants from the dangers of the
effects of fire.
National Electric Code (NFPA 70) - Provides for
proper installation of electrical systems and
equipment.
Some of the major codes requiring firestopping
arrangements are: (continued)
Occupational Safety and Health Standards
(29 CFR Part 1910) - Occupational Safety and
Health Administration (OSHA) requires all
facilities to take steps to provide for minimum
worker protection.
Some situations that could potentially affect the
performance of the installed firestop include:
The type and size of the penetrating items (type
of pipe or wire through the wall or floor)
The percentage of cable fill and the annular space
(the amount of cable and the size of the space it’s
going through)
The type and thickness of the insulation
The type and thickness of the wall or floor
The severity of the fire itself (how bad the fire is
and how hot)
The quality of the installation (how well the
firestop was installed)
You should always install firestopping in the
following locations:
Openings between floor slabs and curtain
walls, including hollow curtain walls at the
floor slabs
Openings and penetrations in enclosures with
time-rated fire doors
Openings between walls and ceilings of timerated assemblies
Figure 3-24: Firestopping Retardant Application
Figure 3-25: Fire Path
The following list names some of these materials
and describes their characteristics:
Cementitious materials are firestopping materials
having properties that are similar to cement.
Cementitious materials come in two basic forms:
Dry powder - water mix
Premixed
Intumescent sheet is used to form a honeycomb
partition opening. Special provisions include:
Layering (one thickness, course, or fold laid over or under another)
Spacing (providing with spaces of placing at intervals)
Anchoring (a reliable or main support)
Sealing (the ability of a component to resist the entrance of
contaminants)
Figure 3-26: Cementitious Mortar Application
The following list names some of these materials
and describes their characteristics: (continued)
Caulk can vary in its ability to:
Adhere (its ability to hold fast or stick)
Flexibility (the capability to adapt to a new, different, or
changing environment)
Some type of caulk remain permanently soft while some cure
to a solid.
Moisture resistance (how well it resists moisture)
The following list mentions several of these
components and collects them into related
groups.
1
Telecom and electrical
Conduit - plastic and metal
Cable - power, control, telephone, fiber optic,
metalclad, coaxial
Bus duct (self-supporting bridge
construction)
Cable tray (a suspended tray that contains
various telephone or computer cables)
The following list mentions several of these
components and collects them into related
groups. (continued)
2
HVAC (air conditioning)
Round openings
Rectangular openings
Insulated openings
Noninsulated openings
Multiple openings
The following list mentions several of these
components and collects them into related
groups. (continued)
3
Mechanical
Piping, insulated and noninsulated:
Plastic: CPVC, PVC, CCPVC, ABS, CCABS, PB, PP,
PVDF, and double containment
Metal: Steel, cast iron, copper, and aluminum
Uses include:
Chiller lines
Sprinkler systems
Water supply lines
Steam lines
Acid drains
Process pipes
DWV
Figure 3-27: Firestop Pillows
A few precautions you should take in order to
properly install and maintain firestop pillows:
Inspecting all areas to be protected
Removing any sharp edges, protruding wires,
or ties that could damage the poly bags
Arranging cables to present a smooth and even
surface
Calculating pillow requirements in square
inches in advance as an indicator of the proper
installed volume and compression
Keeping them away from wire mesh that may
be required as a part of the installation process
or given as an option to facilitate installation
Figure 3-28: Firestop Collar
Figure 3-29: Wrap Strip
Wrap strip installation procedures:
1
(Tuck-in installations) Wrap a layer of wrap
strip around the penetrant. You may use
masking tape to temporarily secure the strip.
Apply successive layers of wrap strip as required
by the system chosen.
2
Secure the wrap strip in place with steel tie wire
or foil tape.
3
It is recommended that both sides of the wall,
and the top and bottom of the floors, be caulked.
Wrap strip installation procedures: (continued)
4
(Restraining collar installations) Calculate the
required length of the restraining collar needed
to completely wrap around the outer diameter of
the wrap strip rings. Include an additional inch
for overlap.
Requirements for Firestop Testing: Exposure to
severe fire under positive pressure
Room temperature must reach 1,000ºF within 5
minutes
Room temperature must reach 1,700º in 1 hour
Room temperature must reach 1,850º in 2 hours
Room temperature must reach 1,925º in 3 hours
Room temperature must reach 2,000º in 4 hours
Requirements for a Hose Stream Test: A
Powerful water hose stream
A 2 1/2-inch hose with a 1 1/8-inch hose nozzle.
A 1 to 3 hour test with water applied at 30 psi
for a specified length of time, based on an
hourly rating and the size of the test surface.
A 4-hour test with water applied at 45 psi for an
extended period of time, based on the size of the
test surface.
Fire rating categories include:
Fire: The rating that provides the time period
for which the system is capable of blocking
passage of flame through the system (and
requires acceptable hose stream performance)
is called the Flame or (F) rating.
Temperature: The Temperature or (T) rating
provides the time period for which the system is
capable of limiting maximum temperature rise in
the unexposed surface of the wall, floor assembly
or the penetrating item, and on the fill material in
the open space—not to exceed 325ºF (181ºC) above
the initial temperature. It also requires acceptable
stream performance.
Fire rating categories include: (continued)
Leakage: The Leakage or (L) rating provides
information concerning the amount of air
leakage, specified in cubic feet per square foot
of an opening, through the firestop system
and/or 40ºF air temperature.
FH Rating: The firestopping system meets the
requirement of an FH rating if it remains in the
opening during both the fire test and the hose
stream test, within the limitations of an (F) rating.
Also, during the hose stream test, the system
should not develop any openings that would
permit a projection of the stream past the
unexposed side.
Fire rating categories include: (continued)
FTH Rating: The firestopping system meets the
requirements established for an FTH rating if
it remains in the opening during the fire test
and the hose stream test, within the limits set
for the (F), (T), and (FH) ratings.
REVIEW QUESTIONS
1
You are installing an underground
conduit for entrance cable. The architect
has left a very old tree on the property
that lies directly between the local service
provider’s service manhole and the
entrance closet. Can you run the conduit
around the tree?
REVIEW QUESTIONS
2
What is the expected electrical voltage
level of an equipment ground?
REVIEW QUESTIONS
3
_________ and _____________ are some
of the main causes of electronic equipment
failure.
REVIEW QUESTIONS
4
Describe a good first-step practice to
employ when troubleshooting an
intermittent network communication
problem.
REVIEW QUESTIONS
5
In a telecommunications installation,
where would you find a TMGB?
REVIEW QUESTIONS
6
How is the TMGB bonded to the building’s
main electrical service grounding
electrode?
REVIEW QUESTIONS
7
When all TGBs in a building are bonded
together along with the TMGB, what
structure is created?
REVIEW QUESTIONS
8
What is the purpose of the protector
unit in a primary protector block?
REVIEW QUESTIONS
9
What is a retrofit installation as it
applies to entrance facilities?
REVIEW QUESTIONS
10 What is the most overriding reason
for implementing firestopping?
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