Chpter 5 Backbone Building Pathways (Internal)

Question 1

What is the most common
type of backbone building
pathway (internal)?

Answer 1

Vertically aligned TRs with
connecting sleeves or slots
TDMM: Page 5-45

Question 2

Why is it considered
desirable to “stack” TRs
with other mechanical
spaces?

Answer 2

Stacking makes the distribution
of telecommunications cables
more efficient because of
shorter conduits, bonding, and
cable runs.
TDMM: Page 5-45

Question 3

Name 3 types of steel
conduit that are commonly
used in backbone
distribution systems.

Answer 3

1 .Rigid metal conduit (RMC)
2. Intermediate metal conduit (IMC)
3. Electrical metallic tubing (EMT)
TDMM: Page 5-46

Question 4

What is the benefit of
specifying the use of RMC
with PVC coating (both
inside and outside) for
underground pathways?

Answer 4

THE PVC COATING PREVENTS RUST.

Question 5

NAME 2 WAYS THAT IMC DIFFERS FROM RMC?

Answer 5

1. HAS THINNER WALL THICKNESS THAT RMC.
2. WEIGHS ABOUT 1/3 LESS THAN RMC.

Question 6

What is the lightest-weight
metallic conduit
manufactured for use in
backbone distribution
systems?

Answer 6

EMT (THIN WALL)

Question 7

What is the required height
for a curb for a slot?

Answer 7

A minimum of =25.4 mm (1 in)
TDMM: Page 5-48

Question 8

How far are sleeves
permitted to extend
above floor level?

Answer 8

MINIMUM OF 25.4 MM (1 IN)
MAXIMUM OF 775 MM (3 IN)

Question 9

Why should you leave at
least -25.4 mm (1 in)
between sleeves and the
wall or other sleeves?

Answer 9

TO ALLOW ROOM FOR BUSHINGS.

Question 10

Name 2 potential negative
consequences of placing
sleeves too far from
the wall.

Answer 10

1 .May become a tripping hazard
2.May create too great a cable
span from the sleeve to the
backboard/tray
TDMM: Page 5-48

Question 11

Per the TDMM, what is the
baseline requirement for
sleeves per floor?

Answer 11

FOUR 103 METRIC DESIGNATOR (4 TRADE SIZE) SLEEVS + ONE ADDITIONAL 103 DESIGNATOR (4 TRADE SIZE) SLEEVE FOR EACH 3716 M2 (40,000 FT2) OF USABLE FLOOR SPACE SERVED.

Question 12

What is the maximum
number of rows of sleeves
that should be used?

Answer 12

The number should be restricted
to 2 whenever practicable.
TDMM: Page 5-50

Question 13

True or False
Slots should be designed to
have the widest depth
permitted.

Answer 13

False. Preference should be
given to narrower depths
whenever possible.
TDMM: Page 5-50

Question 14

Who is responsible for
approving the location and
configuration of slots?

Answer 14

STRUCTURAL ENGINEER

Question 15

Who is typically responsible
for directing cable shaft
use requirements?

Answer 15

BULIDING MANAGERS

Question 16

True or False
Backbone cable pathways
are permitted in elevator
shafts.

Answer 16

False. Backbone cable
pathways cannot be located
in elevator shafts.
TDMM: Page 5-51