Submittal

network throughout the building. e communications
installer can complete the grounding of the busbar to the
equipment. Oen, electricians are hired to build the grid of
CBN conductors under the raised access floor. Even in this
case, little thought is given to how the grounding network
bonds to the equipment.
Alarmingly, numerous data centers in operation today have
grounding busbars in place, and a grid of CBN conductors un-
der a raised floor, but not a single rack or cabinet bonded to
the CBN. It is clear that the data center owner intended to have
grounding; however, if the racks and cabinets are not bond-
ed to the grounding system, then there is no protection. Cre-
ating electrical continuity within racks and cabinets is best
accomplished during initial installation. is is also the best
time to create the bond from the rack to the CBN before it is
forgotten. Equipment that is installed on the racks should be
bonded at this time.
It makes sense that the contractor who installs racks, cabi-
nets, and equipment is in the best position to create the parts
of the grounding system that go along with the installation.
Collectively, this lets you be better positioned with customers
by providing valuable information that educates data center
decision-makers on how to protect their investment.
You should include a separate line item in bid submittals for
upgrading to a TIA-942-compliant grounding system, even if
the data center has not requested such an upgrade. is inclu-
sion lets you make a competitive bid, to engage the customer
in a conversation about TIA-942 grounding, and ultimately
to create some distance from your competition.
Common problems and solutions
Data centers oen run into trouble with their grounding sys-
tems when any of the following mistakes are made:
• Using the wrong type of grounding connectors. For exam-
ple, connectors that use setscrews to fasten the conductor
can loosen over time, degrading the electrical bond.
• Applying hardware, such as screws and washers, that are
not designed to make an electrical bond, resulting in un-
grounded equipment.
• Failing to create an electrical bond between the structural
components of racks and cabinets can trap currents within
sections of them, resulting in potential safety hazards, fail-
ure of ESD protection, and ungrounded equipment.
A kitted grounding system can help installers avoid the mis-
takes that plague data centers. Key features of a good ground-
ing system should include:
• Permanent copper compression lugs that do not loosen
over time;
• Hardware, such as thread-forming screws and paint-pierc-
ing washers, and studs that cut through the durable finish-
es that coat data center racks and cabinets, thereby creating
a metal-to-metal connection (bond);
• Components, such as hardware and jumper cables, that
are tested for their ability to create electrical bonds and
carry current.
Additionally, the kitted system should comply with TIA-942
and fit any rack or cabinet that complies with the EIA-310D
standard. Everything necessary to provide a TIA-942-compli-
ant installation should be included in the kit, such as grounding
strips, busbars, and jumpers for creating electrical continuity
throughout a rack or cabinet; antioxidant to guarantee the
long-term reliability of the electrical bonds; and instructions
that describe the proper installation techniques (helps simpli-
fy ordering of grounding components and minimizes the risk
of overlooking details).
Each component and connection in the system is critical
to creating a low-impedance grounding path. In addition to
using components that are listed by a nationally recognized
testing laboratory, such as Underwriters Laboratories (UL),
the jumper assemblies within the kits should also be listed to
UL 467 Grounding and Bonding Equipment as a means of fur-
ther certifying their applicability to grounding.
Ideally, components that make up the grounding kits are
tested to determine their ability to function during real-
world conditions, such as earthquakes, lightning strikes, and
AC power faults. Telcordia Technologies’ NEBS Level 3 test
of power connectors simulates response to these events and
other scenarios that are likely in the data center environment.
(For more information, see e Electrical Distributor, January
2004, “Minimize Service Interruptions.” www.tedmag.com).
NEBS Level 3 is the most stringent test available to the indus-
try, and power connectors that meet NEBS Level 3 should be
specified for data centers at every tier level.
Business booster
Network grounding provides a win-win opportunity for you,
and for data center managers. If you, as a contractor, under-
stand the value of a well-designed system, you can provide ex-
pert consultative services and enhance your positioning as a
valuable partner.
To avoid the problems that are common in network ground-
ing systems, you should implement only engineered solutions
that comply with accepted industry standards, such as TIA-942
and NEBS Level 3. And following proper network grounding
practices will provide your customers with the highest level
of network grounding capability.