C H A P T E R  3

Environmental and Electrical Specifications

This chapter describes the environmental and electrical requirements for Sun Fire E2900 systems. It contains the following sections:

3.1 Environmental Requirements

The design of your environmental control system--such as computer room air-conditioning units--must ensure that intake air to the server system complies with the limits specified in this section.

To avoid overheating, do not:

TABLE 3-1 lists the environmental limits for Sun Fire E2900 systems. The system can be installed in an environment with the specific operating ranges shown in TABLE 3-1.


TABLE 3-1 Environmental Limits for Sun Fire E2900 Systems

Environmental Factor

Operating Range

Non-Operating Range


Ambient temperature[1]

41° to 95°F (5° to 35°C)
up to 550 yards (500 meters)[2]

-40° to 149°F
(-40° to 65°C*)

69.8° to 73.4°F
(21° to 23°C*)

Relative humidity[3]

10 to 90% non condensing
80.6° (27°C) maximum wet bulb

10 to 90% non condensing
100.4° (38°C) maximum wet bulb

45 to 50% non condensing


For UltraSPARC IV+ 1.8 GHz CPU/Memory boards only, maximum 7000 feet (2134 meters)

All other CPU/Memory boards, maximum 10000 feet
(3048 meters)

maximum 39400 feet (12000 meters)


The operating environmental limits in TABLE 3-1 reflect systems testing. The optimum condition is the suggested operating environment. Operating computer equipment for extended periods at or near the temperature or humidity extremes is known to significantly increase the failure rate of hardware components. It is strongly suggested that customers plan and use the optimal temperature and humidity ranges in order to minimize any chance of downtime due to component failure.

3.1.1 Ambient Temperature

The ambient temperature range of 69.8° to 73.4°F (21°C to 23°C) is optimal for system reliability and operator comfort levels. Most computer equipment can operate within a wide temperature range, but a level near 71.6°F (22°C) is desirable because it is easier to maintain safe associated relative humidity levels at this temperature. Operating in this temperature range provides a safety buffer in the event the environmental support systems go down for a period of time. Though individual standards vary slightly, 69.8° to 73.4°F (21°C to 23°C) should be used as an optimal setting.

3.1.2 Ambient Relative Humidity

The ambient relative humidity levels between 45 percent and 50 percent are the most suitable for safe data processing operations. Under certain circumstances, most data processing equipment can operate within a fairly wide environmental range (20 percent to 80 percent), but the optimal goal should be between 45 percent to 50 percent for the following reasons:

Electrostatic discharge (ESD) is easily generated and less easily dissipated in areas where the relative humidity is below 35 percent. ESD becomes critical when levels drop below 30 percent. The 5 percent relative humidity range might seem unreasonably tight when compared to the guidelines used in typical office environments or other loosely controlled areas. However, it is not as difficult to maintain in a data center because of the high efficiency vapor barrier and low rate of air changes normally present.

3.2 Airflow and Heat Dissipation

The maximum rate of heat release from a Sun Fire E2900 system with all slots occupied and active is 3720 W (12683.38 British Thermal Units (BTU) per hour). TABLE 3-2 shows detailed figures.

TABLE 3-2 Heat Dissipation


Heat Dissipation



Sun Fire E2900


4 CPUs, 8 Gbytes memory

1540W (5250.64 BTU/hr)


8 CPUs, 16 Gbytes memory

2430W (8285.11 BTU/hr)


12 CPUs, 24 Gbytes memory

3320W (11319.58 BTU/hr)


12 CPUs, 96 Gbytes memory

3720W (12683.38 BTU/hr)


The Sun Fire E2900 system has been designed to function while mounted in a natural convection airflow. The following rules must be followed to meet the environmental specification.

3.3 Sun Fire E2900 System Power Requirements

The Sun Fire E2900 system is supplied ready for installation in an equipment rack.

Note - The voltage must be in the range 200-240 VAC for the system to power on.

The Sun Fire E2900 system is supplied with four detachable power cords fitted with wall plugs to mate with the local electrical socket outlets. TABLE 3-3 shows the power cord ratings.

Note - The plug at the end of each power cord is the primary means of disconnection for this product.

TABLE 3-3 Sun Fire E2900 System AC Power Cord Ratings




200 to 240 VAC

Maximum input current per cord

9A at 200 VAC

Line cord

10A nominal

Circuit breakers - North America (4)

15A to 20A

Circuit breakers - international (4)


TABLE 3-4 shows the on-site AC power requirements.

TABLE 3-4 Sun Fire E2900 System Power Requirements




200 to 240 VAC


50 to 60 Hz

TABLE 3-5 shows the current and power consumption of the Sun Fire E2900 system at 200 VAC.

TABLE 3-5 Sun Fire E2900 System Current and Power Consumption




9A per cord, if only two cords are powered

Inrush Current

18A after 100 mu symbols

Surge Current

After 5 ms brown-out short term surge is higher at 75A

Power Consumption

3300W max. total

3.3.1 Grounding Requirements

The Sun Fire E2900 system enclosure has an additional safety earth bonding point.

This bonding point must meet the central office requirements for enclosure or shelf grounding in GR1089-CORE. This is for a path between the unit system and enclosure metal or nearby point on the central office ground system.

The use of this bonding point connection is optional and is generally dependent on the equipment practice of the installer.

This bonding point is independent of the safety ground connection for the power system grounding, which is provided by the earth wire present in each of the power cords. This connection must be present.

3.3.2 Connecting AC Power for Redundancy

caution icon

Caution - For optimum redundancy, the power cords should be connected to two independent power sources (two power cords for each power source).

Most commonly, two independent power sources means an outside power line as one source and an uninterrupted power supply backup system (UPS) as the second source. That way, if a single power source should fail, the system will continue to function.

Each power cable should have its own circuit breaker.

The system will not enter standby unless two system power supplies have AC inputs in range.

Figure charting 150A surge after brown-out of up to 75 ms..



1 (TableFootnote) Does not apply to removable media devices.
2 (TableFootnote) Maximum ambient operating temperature is derated by 1 degree C per 500m elevation.
3 (TableFootnote) Subject to a maximum absolute humidity of 0.024 kg of water per kg of dry air.