Installation guide

52 Elements of Network Planning
890 USE 100 00
2.3 Defining the Network Layout
2.3.1 Component Locations
The maximum cable length allowed for the network section from end to
end is 1500 ft (450 m). Up to 32 nodes can be connected within this
length. The maximum length includes the total set of cable runs,
including all horizontal runs and vertical cable drops to the networked
devices. On dual-cable networks, the difference in length between
cables A and B must not exceed 500 ft (150 m) between any two nodes
on the same cable section. This is explained in more detail on the next
page.
The minimum length allowed between any two points is 10 ft (3 m). If
two devices are closer than this, you must include extra cable to attain
the minimum cable length.
2.3.2 Environmental Requirements
You should select a cable routing method that will protect the cable
from physical damage and potential electrical interference sources.
Avoid areas of high temperature, moisture, vibration, or other
mechanical stress. Secure the cable where necessary to prevent its
weight and the weight of other cables from pulling or twisting the
cable. Plan the cable layout to use cable ducts, raceways, or other
structures for protecting the cable. These structures should be
dedicated for signal wiring paths, and should not contain power wiring.
Avoid sources of electrical interference that can induce noise into the
cable. Use the maximum practicable separation from such sources.
Follow these cable routing guidelines for electrical protection:
V Maintain a minimum separation of 3.3 ft (1 m) from the following
equipment: air conditioners, elevators, escalators, large blowers,
radios, televisions, intercom and security systems, fluorescent,
incandescent, and neon lighting fixtures.
V Maintain a minimum separation of 10 ft (3 m) from the following
equipment: power wiring, transformers, generators, and
alternators.