Submittal
Source: Panduit
0605cidef2
Grounding strips
for cabinet
mounting rails
Paint piercing
hardware
Grounding busbar
NEBS Level 3
compression lugs
Grounding jumper
Kits engineered for network grounding
tier requirements is a complex process, encompassing expertise
in a wide range of technical specialties, including architecture,
cabling infrastructure, electrical design, environmental con-
trol, and fire protection. To make this task more manageable,
TIA-942 provides design guidelines to help meet the uptime re-
quirements of each tier level.
For example, when designing a Tier I
data center, TIA-942 states, “A data center
grounding infrastructure is not required, but
may be desirable as an economic method to
satisfy equipment manufacturers’ grounding
requirements.” At Tiers III and IV, the data
center infrastructure grounding system is ab-
solutely required.
Contractors are ideally positioned to pro-
vide much of the network grounding system,
and those who understand these require-
ments can provide a value-added service—
the expertise to help customers understand
and implement the necessary grounding sys-
tem to improve their data center.
Network grounding design
e two goals of the grounding system are to
equalize electrical potentials and to create a
low resistance path to ground. Five basic principles are used when
designing a grounding system to accomplish these goals:
1. e grounding system shall be intentional. Careful plan-
ning must be given to network grounding, just like any other
system deployed in the data center. As the grounding system
is no more reliable than its weakest link, only high-quality
components can be used and trained professionals must make
all connections.
2. e grounding system shall be visually verifiable. When im-
plemented properly, you should be able to visually inspect ev-
ery component of the grounding system, from the equipment,
to the rack, to the common bonding network (CBN), to the
earth. Such a system can be inspected for degradation and is
accessible during moves, adds, and changes (MACs), ensur-
ing long-term system reliability and scalability.
3. e grounding system shall be adequately sized. TIA-942
provides guidelines for each component of the grounding sys-
tem. Improper use of the guidelines can reduce network avail-
ability and cause premature equipment failure that contributes
to increased operating costs.
4. e grounding system shall direct damaging currents away
from equipment. A grounding system that complies with
TIA-942 requires each rack to bond directly to the CBN, there-
by directing current away from sensitive electronics. For in-
stance, a common error is to daisy-chain racks together.
During a surge event, the entire row of daisy-chained racks
becomes energized with stray current, potentially resulting in
additional damaged equipment.
5. All metallic components in the data center shall be bonded
to the grounding system. e goal is to have all conductive ma-
terials at the same electrical potential to minimize current flow.
Current flows when there is a difference in potential between
components. If the current flows across a piece of equipment,
damage may occur. Equip-
ment, racks, cabinets, lad-
der racks, enclosures, and
cable trays must be bond-
ed to the grounding system.
(Additional information is
available in the white paper,
Facility Considerations for
the Data Center, authored by American Power Conversion,
Cisco Systems, and Panduit Corp.)
e grounding section of TIA-942 offers guidelines that
meet the basic principles and adds additional details specific
to the modern data center environment. One important issue
is the creation of electrical continuity throughout racks and
cabinets. Because most racks and cabinets are made of paint-
ed components that are bolted together, there is no guaran-
tee that electrical continuity exists from one rack component
to the next. In the data center, rack and cabinet continuity
is important for safety; electrostatic discharge (ESD) protec-
tion; and the proper grounding of switches, servers, and power
strips. Continuity may not exist if the installer fails to scrape
paint between sections of rack or use specially designed paint-
piercing hardware.
Network grounding installation
A licensed electrician is required to bond the AC power pan-
el. Additionally, the electrician typically installs the busbar
Kits made specifically for network
grounding include: grounding
jumpers, NEBS Level 3 compres-
sion lugs, paint-piercing hard-
ware, grounding strips for cabinet
mounting rails, and grounding
busbars.