Ensuring 99.995% availability—the requirement of the ANSI/TIA-942-B standard for Tier IV data centers—means accepting a maximum of 26 minutes of unplanned downtime per year. This level can only be achieved with total electrical redundancy (2N), rigorous maintenance, and continuous monitoring of each link in the power chain.

The mathematics of reliability

• Total annual time: 525,600 minutes

• Permitted downtime: 0.005% → ≈ 26 minutes/year

In environments that host financial transactions, artificial intelligence, or healthcare services, every minute of downtime represents a high financial and operational risk.

Critical points in electrical infrastructure

MTBF (Mean Time Between Failures) studies indicate that the main causes of failures in mission-critical installations are connections subject to progressive heating. These include:

• Shielded busbars and medium- and low-voltage distribution bars.

• UPS panels, PDUs, and static transfer panels.

• Battery bank terminals and rectifier interconnections.

• Isolation transformers and tap switches.

Without continuous thermal monitoring, micro-increases in electrical resistance can lead to catastrophic failures.

ANSI/TIA-942-B standard: the basis for Tier classification

ANSI/TIA-942-B is the international reference for data center design and evaluation. It defines criteria for architecture, electrical, mechanical, and telecommunications infrastructure, as well as redundancy, contingency, and availability requirements that classify facilities into Tiers I through IV. Tier IV, the highest level, requires complete redundancy (2N), fault tolerance, and concurrent maintainability. The standard also establishes SLA (Service Level Agreement) metrics which, for Tier IV, correspond to 99.995% availability, i.e., only ≈26 minutes of annual downtime, making it a fundamental parameter for mission-critical projects.

DISCOVER:

Varixx ZYGGOT® SG: Online Thermography System for Low Voltage

Varixx's ZYGGOT® SG is an online thermography system for low-voltage electrical assets with self-addressable networked sensors and contact measurement. Integrated with industrial supervisory systems, it was designed with mission-critical data centers, such as Tier IV, in mind and combines:

1. It is a disruptive, cost-optimized solution with ultra-compact sensors for contact temperature monitoring for low voltage. The sensors are self-addressable, digital, and networked via 1-wire. The system is scalable, easy to install, and can be integrated with the main industrial communication protocols.

2. The ZYGGOT® system continuously monitors the temperature of connections and busbars, detecting early any abnormal heating that could lead to serious failures, such as short circuits or even fires. This constant monitoring reduces the need for traditional inspections. It prevents unexpected downtime, which means lower corrective maintenance costs and more uninterrupted operating time. At the same time, the solution is economical and scalable: a single gateway can receive data from hundreds of self-addressable sensors, allowing for expansion of monitoring without a proportional increase in investment. Its architecture is ready to integrate with industrial supervision systems using recognized protocols such as Modbus (RTU and TCP), MQTT (IoT), RESTful API, EtherNet/IP, and IEC-61850, which facilitates connection to automation platforms, control centers, or applications in data centers and mission-critical environments.

How it works?

Self-addressable temperature sensors are installed at critical points and connected to a 1-Wire network. They continuously send readings to a gateway, which concentrates the data. The gateway makes this information available in real time on a local display, web interface, or via industrial protocols for supervision systems. The gateway has a NO/NC (dry contact) output that can be configured to be triggered if any sensor exceeds the individually programmed values.

• Installation – ultra-compact, self-addressing sensors applied directly to busbars and energized connections.

• High-precision measurements – proven stability even under large variations in current and load.

• Native integration – immediate communication with DCIM, BMS, and automation systems via IEC 61850, Modbus RTU/TCP, MQTT, and RESTful API, ensuring full interoperability, open standards, and 2N redundancy.

• Predictive intelligence – instant alarms, historical records, and trend analysis for planned maintenance.

• Direct contribution to 99.995% SLA – increases MTBF, extends asset life, and reduces OPEX costs.

This architecture transforms temperature measurement into an essential layer of reliability engineering, helping to ensure the actual availability required by ANSI/TIA-942-B.

Operational benefits for Tier IV

• 99.995% SLA protection, reducing the likelihood of unplanned downtime.

• Increased MTBF, with greater predictability and lower corrective maintenance costs.

• Extended life cycle of buses, UPS, and batteries, reducing CAPEX and OPEX.

Conclusion

Achieving 99.995% uptime is not just a contractual goal; it is an engineering requirement for reliability. With continuous thermal monitoring, Varixx's ZYGGOT® SG transforms temperature measurement into an essential layer of security and availability, helping Tier IV data centers to meet, in practice, the level of reliability that certification requires.