Commercial Power Requirements - Nortel Meridian 1 Option 11C Planning And Installation Manual

Commercial power requirements

• Metallic conduit is liable to corrode over time, particularly at threaded
connections. Such corrosion will increase resistance significantly. This
problem is compounded when multiple links are involved.
Application(s) of paint over the conduit may accelerate the corrosion
process.
• Conduit is required to be anchored to secure surfaces. Often, it is bolted
to structural steel members, which may function as ground conductors to
very noisy equipment, such as compressors, motors, and so on. The
coupling of these noisy signals into the Option 11C grounding system
may seriously impair its performance. The resulting intermittent
malfunctions can be difficult to trace.
The Option 11C system is available in both AC-powered and DC-powered
versions.
AC-powered version
The AC-powered version is presented in two separate sections in this
Chapter:
• Optimal AC-powered installation
• Alternative AC-powered installation
The optimal installation of an AC-powered Option 11C system consists of a
direct connection to the electrical system in the building, provided certain
requirements are met. Refer to AC-powered installation later in this chapter
for detailed information.
Alternatively, an approved isolation transformer may be used for
AC-powered systems, where meeting the optimum requirements may be too
expensive or may not be achievable. See "Alternative AC-powered
installation" on page 45.
DC-powered version
With the DC-powered version of Option 11C, each cabinet is powered solely
from a DC power source. See DC-powered version later in this chapter for
detailed information.
System and site requirements Page 43 of 408
Option 11C Planning and Installation Guide