Sun Fire V1280/Netra 1280 Systems Site Planning Guide

This chapter describes the environmental and electrical requirements for Sun Fire V1280/Netra 1280 systems. It contains the following sections:

• Section 3.1, Environmental Requirements
• Section 3.2, Airflow and Heat Dissipation
• Section 3.3, Sun Fire V1280 System Power Requirements
• Section 3.4, Netra 1280 System Power Requirements

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3.1 Environmental Requirements

The system can be installed in an environment with the specific operating ranges shown in TABLE 3-1.

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:

• Guard against directing any warm air toward the front of the cabinet.
• Guard against directing warm air toward the system access panels.

TABLE 3-1 lists the environmental limits for Sun Fire V1280/Netra 1280 systems.

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:

• Optimal range helps protect computer systems from corrosivity problems associated with high humidity levels.
• Optimal range provides the greatest operating time buffer in the event of environmental control system failure.
• This range helps avoid failures or temporary malfunctions caused by intermittent interference from static discharges that might occur when relative humidity is too low.

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; where as, 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.

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3.2 Airflow and Heat Dissipation

The maximum rate of heat release from a Sun Fire V1280/Netra 1280 system with all slots occupied and active is 3300 W (11300 British Thermal Units (BTU) per hour). TABLE 3-2 shows detailed figures.

The Sun Fire V1280/Netra 1280 system has been designed to function while mounted in a natural convection airflow. The following rules must be followed to meet the environmental specification.

• Ensure adequate airflow through the system. The Sun Fire V1280/Netra 1280 system uses internal fans that can achieve a total airflow of 400 cubic feet of air per minute (cfm) in normal operating conditions.
• The system has front-to-back cooling. The air inlet is at the front of the system. The exhaust exits from the rear of the system.
• Ventilation openings for both the inlet and exhaust of the system should provide a minimum open area of 160 inches² (1030 cm²) each.
• Allow a minimum of clearance of 35 inches (86 cm) at the front and rear of the system for adequate ventilation.
• Ensure that additional equipment installed in the cabinet does not exceed environmental limits at the air inlet. The environmental limits assume the system is operating in the system cabinet with ventilated doors closed.

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3.3 Sun Fire V1280 System Power Requirements

The Sun Fire V1280 system is supplied ready for installation in an equipment rack.

The Sun Fire V1280 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.

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

TABLE 3-5 shows the current and power consumption of the Sun Fire V1280 system at 200 VAC.

3.3.1 Grounding Requirements

The Sun Fire V1280 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 - 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 in range AC inputs.

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3.4 Netra 1280 System Power Requirements

The Netra 1280 system is supplied ready for installation in an equipment rack.

Caution - This system has multiple power connections. You must open all associated circuit breakers in order to completely remove power from the system.

Caution - The power switch is not an On/Off switch. This power switch is an On/Standby switch. It does not isolate the equipment. The circuit breakers are the primary means for isolating the Netra 1280 system.

The power switch of the Netra 1280 system is a rocker style momentary action switch. This switch controls only low voltage signals. No high voltage circuits pass through this switch.

At least two dedicated power sources should be provided with positive-ground circuit breakers, see Section 3.4.2, Connecting DC Power for Redundancy for details. Connector lugs are provided for crimping on to customer-supplied cables.

The Netra 1280 system is supplied with connections for four feed pairs. TABLE 3-6 shows the feed-pair current ratings.

TABLE 3-7 shows the current and power consumption of the Netra 1280 system at -48 VDC.

FIGURE 3-1 Surge Current

3.4.1 Source Site Requirements

The DC source must be:

• -48 VDC or -60 VDC nominal centralized DC power system
• Electrically isolated from any AC power source
• Reliably connected to earth (the battery room positive bus is connected to the grounding electrode)
• Rated for a minimum of 50A per feed pair

3.4.1.1 Grounding Requirements

The Netra 1280 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 is independent of the safety ground connection for the power system grounding, which is provided by the two-hole connection on the DC inlet module.

3.4.1.2 Overcurrent Protection Requirements

Overcurrent protection devices must be provided as part of each host equipment rack.

• Four 50A single-pole, fast trip, DC-rated circuit breakers (one per ungrounded supply conductor) must be located in the negative supply conductor between the DC power source and the Netra 1280 system.
• Circuit breakers must not trip when presented with inrush current of 60A lasting 200 ms.

3.4.1.3 Disconnection and Isolation

The disconnect devices for servicing are defined as the circuit breakers in all negative supply conductors.

3.4.2 Connecting DC Power for Redundancy

Caution - For optimum redundancy, the feed pairs should be connected to two independent power sources (two feed pairs to 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.

^{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.}

^{4 (TableFootnote) The worst case input current for each power supply is drawn when only two of the four power supplies have supplied power. If the supply voltage is below -48V, then the current rises to a maximum of 47A.}

Sun Fire V1280/Netra 1280 Systems Site Planning Guide

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