3.2.1System Grounding and Bonding

The performance and safety of any TVSS system is dependent on proper grounding and bonding. Grounding is required primarily for safety. Correct implementation also enhances equipment per- formance. Incorrect grounding can reduce or impede the TVSS's operation.

All electrical circuits to the TVSS must include an equipment grounding conductor as required by the NEC and local codes.

An insulated grounding conductor is required in addition to any metallic raceway that may be used as a grounding conductor. For parallel-connected TVSSs, the grounding conductor should be the same wire size as the associated power conductors. Grounding conductors must be routed with the associated power conductors in the same raceway (conduit).

When metallic raceways are used, adequate electrical continuity must be maintained at all race- way connections, particularly raceway terminations to the electrical enclosures.

The use of isolating bushings or other means to interrupt a metallic conduit run is a potential safety hazard and is not recommended.

Grounding Electrode—Transient voltage surge suppressors do not discharge all surges to ground (earth). Transient voltage surge suppressors divert the surge current back to its source to complete the electrical circuit.

In the case of lightning whose potential is developed with respect to the earth, the TVSS diverts the surge current to the grounding electrode (earth connection). However, for most transient surges which are developed by switching loads, the TVSS diverts the surge current back to its source without involving the grounding electrode.

For proper TVSS performance, the service entrance grounding electrode system must comply with the NEC by having all available electrodes (building steel, metal water pipe, driven rods, concrete encased electrodes, etc.) properly bonded together and connected to the power system grounding.

! CAUTION

The use of a separate grounding electrode to ground the TVSS defeats the effectiveness of the TVSS, is a potential safety hazard, and may cause equipment damage. The arrestor grounding conductor must be connected per NEC 280-21.

! CAUTION

For proper and safe operation, the neutral, (if provided), must be reliably connected to the neutral of the source. Failure to provide a reliable neutral connection may result in module failure!

Electrical Connections

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Liebert II manual System Grounding and Bonding
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II specifications

Liebert II is a high-performance precision cooling system designed specifically for mission-critical applications, ensuring that data center facilities maintain optimal temperatures for sensitive equipment. As part of Emerson's extensive line of cooling solutions, the Liebert II is particularly valued for its reliability, efficiency, and adaptability.

One of the standout features of the Liebert II is its sophisticated cooling technology, which incorporates both chilled water and air-cooled systems. This dual capability allows it to operate effectively in a variety of environments, whether in a small server room or a large data center. The unit is engineered to deliver consistent cooling across different loads, catering to fluctuating demands characteristic of modern IT environments.

In terms of performance, the Liebert II boasts variable speed fans that adjust to the cooling requirements in real-time, thus maximizing energy efficiency. This feature not only reduces operational costs but also minimizes the carbon footprint of the facility. Furthermore, the system is designed with advanced electronic controls that offer precise temperature management, allowing for rapid response to any changes in operating conditions.

The Liebert II also includes state-of-the-art monitoring and control features. It supports integration with advanced Building Management Systems (BMS), providing operators with the tools to oversee performance metrics, detect potential issues before they escalate, and implement energy-saving strategies. This level of operational visibility is crucial for maintaining uptime in critical environments.

Another significant characteristic of the Liebert II is its modular design, which simplifies maintenance and scalability. Facilities can easily upgrade or expand the system as needs evolve, ensuring that the cooling solution can keep pace with technological advancements and increased loads. The design also promotes ease of access for service technicians, minimizing downtime during maintenance activities.

Finally, noise reduction is an important aspect of the Liebert II’s design. The system operates quietly, making it suitable for environments where noise levels must be kept at a minimum, such as offices adjacent to IT spaces.

In summary, the Liebert II stands out as a top choice for ensuring reliable precision cooling in data centers, thanks to its advanced technology, energy efficiency, modular design, and operational flexibility. These attributes position it as an essential component in the infrastructure of any modern facility relying on high-performance computing.
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