Nortel Meridian Meridian 1, Planning, Installation And Operating Instructions

Page: 44 / 556

Chapter 3 — System and site requirements Page 25 of 536
Option 11C Compact Planning, Installation, Fault Clearing and CCBR Guide
• Metallic conduit is liable to corrode over time, particularly at threaded
connections. Such corrosion increases resistance significantly. This
problem is compounded when multiple links are involved. Applications
of paint over the conduit may accelerate the corrosion process.
• Conduit is usually 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 Compact grounding
system may seriously impair its performance. The resulting intermittent
malfunctions can be difficult to trace.
Commercial power requirements
The Option 11C Compact system uses commercial ac power as a power
source.
There are two types of ac-powered installations that can be used with the
Option 11C Compact system:
• Optimal ac-powered installation
• Alternative ac-powered installation
Optimal power
The optimal power installation for a Option 11C Compact system consists of
a direct connection to the electrical system in the building, provided certain
requirements are met.
See “Optimal power installation” on page 26.
Alternative power
Alternatively, where meeting the optimum requirements may be too
expensive or may not be achievable, an approved isolation transformer may
be used.
See “Alternative power installation” on page 29.
WARNING
If conduit link separation occurs anywhere between the Option 11C
Compact system and the building ground reference, the conduit is
incapable of providing a ground path. This is a hazardous situation.