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RPS Site Guidelines and Requirements

 

General Site Guidelines

Efficient device operation requires proper site planning and maintenance and proper layout of the equipment, rack or cabinet (if used), and wiring closet.

To plan and create an acceptable operating environment for your device and prevent environmentally caused equipment failures:

  • Keep the area around the chassis free from dust and conductive material, such as metal flakes.

  • Follow prescribed airflow guidelines to ensure that the cooling system functions properly and that exhaust from other equipment does not blow into the intake vents of the device.

  • Follow the prescribed electrostatic discharge (ESD) prevention procedures to prevent damaging the equipment. Static discharge can cause components to fail completely or intermittently over time.

  • Install the device in a secure area, so that only authorized personnel can access the device.

Site Electrical Wiring Guidelines

Table 1 describes the factors you must consider while planning the electrical wiring at your site.

Warning

You must provide a properly grounded and shielded environment and use electrical surge-suppression devices.

Avertissement Vous devez établir un environnement protégé et convenablement mis à la terre et utiliser des dispositifs de parasurtension.

Table 1: Site Electrical Wiring Guidelines

Site Wiring Factor

Guidelines

Signaling limitations

If your site experiences any of the following problems, consult experts in electrical surge suppression and shielding:

  • Improperly installed wires cause radio frequency interference (RFI).

  • Damage from lightning strikes occurs when wires exceed recommended distances or pass between buildings.

  • Electromagnetic pulses (EMPs) caused by lightning damage unshielded conductors and electronic devices.

Radio frequency interference

To reduce or eliminate RFI from your site wiring, do the following:

  • Use a twisted-pair cable with a good distribution of grounding conductors.

  • If you must exceed the recommended distances, use a high-quality twisted-pair cable with one ground conductor for each data signal when applicable.

Electromagnetic compatibility

If your site is susceptible to problems with electromagnetic compatibility (EMC), particularly from lightning or radio transmitters, seek expert advice.

Some of the problems caused by strong sources of electromagnetic interference (EMI) are:

  • Destruction of the signal drivers and receivers in the device

  • Electrical hazards as a result of power surges conducted over the lines into the equipment

Rack Requirements

You can mount the device on two-post racks or four-post racks.

Rack requirements consist of:

  • Rack type

  • Mounting bracket hole spacing

  • Rack size and strength

  • Rack connection to the building structure

Table 2 provides the rack requirements and specifications.

Table 2: Rack Requirements and Specifications

Rack Requirement

Guidelines

Rack type

You can mount the device on a rack that provides bracket holes or hole patterns spaced at 1-U (1.75 in. or 4.45 cm) increments and meets the size and strength requirements to support the weight.

A U is the standard rack unit defined by the Electronic Components Industry Association (http://www.ecianow.org).

Mounting bracket hole spacing

The holes in the mounting brackets are spaced at 1-U (1.75 in. or 4.45 cm), so that the device can be mounted in any rack that provides holes spaced at that distance.

Rack size and strength

  • Ensure that the rack complies with the size and strength standards of a 19-in. rack as defined by the Electronic Components Industry Association (http://www.ecianow.org).

  • Ensure that the rack rails are spaced widely enough to accommodate the external dimensions of the device chassis. The outer edges of the front mounting brackets extend the width of the chassis to 19 in. (48.2 cm).

  • The rack must be strong enough to support the weight of the device.

  • Ensure that the spacing of rails and adjacent racks provides for proper clearance around the device and rack.

Rack connection to building structure

  • Secure the rack to the building structure.

  • If your geographical area is earthquake-prone, secure the rack to the floor.

  • Secure the rack to the ceiling brackets as well as wall or floor brackets for maximum stability.

Cabinet Requirements

You can mount the device in a cabinet that contains a 19-in. rack.

Cabinet requirements consist of:

  • Cabinet size

  • Clearance requirements

  • Cabinet airflow requirements

Table 3 provides the cabinet requirements and specifications.

Table 3: Cabinet Requirements and Specifications

Cabinet Requirement

Guidelines

Cabinet size

  • The minimum cabinet size is 36 in. (91.4 cm) depth. Large cabinets improve airflow and reduce chances of overheating.

Cabinet clearance

  • The outer edges of the front mounting brackets extend the width of the chassis to 19 in. (48.2 cm).

  • The minimum total clearance inside the cabinet is 30.7 in. (78 cm) between the inside of the front door and the inside of the rear door.

Cabinet airflow requirements

When you mount the device in a cabinet, ensure that ventilation through the cabinet is sufficient to prevent overheating.

  • Ensure adequate cool air supply to dissipate the thermal output of the device or devices.

  • Ensure that the hot air exhaust of the chassis exits the cabinet without recirculating into the device. An open cabinet (without a top or doors) that employs hot air exhaust extraction from the top ensures the best airflow through the chassis. If the cabinet contains a top or doors, perforations in these elements assist with removing the hot air exhaust.

  • Install the device in the cabinet in a way that maximizes the open space on the side of the chassis that has the hot air exhaust.

  • Route and dress all cables to minimize the blockage of airflow to and from the chassis.

  • Ensure that the spacing of rails and adjacent cabinets is such that there is proper clearance around the device and cabinet.

  • A cabinet larger than the minimum required provides better airflow and reduces the chance of overheating.

Clearance Requirements for Airflow and Hardware Maintenance for an EX Series Redundant Power System

When planning the site for installing a Redundant Power System (RPS), you must allow sufficient clearance around the installed unit (see Figure 1).

Figure 1: Clearance Requirements for Airflow and Hardware Maintenance for an RPS
Clearance Requirements for Airflow and Hardware Maintenance
for an RPS

Airflow is established by the fans in the power supplies—these fans push air out of the power supply side of the RPS. Therefore, air flows from the connector side of the RPS through the unit and out the power supply side of the RPS. Ensure that cool air is available on the connector side of the RPS.

  • If you are mounting an RPS on a rack or cabinet with other equipment, ensure that the exhaust from other equipment does not blow into the intake vents on the connector side of the chassis.

  • Leave at least 24 in. (61 cm) both in front of and behind the RPS. For service personnel to remove and install hardware components, you must leave adequate space at both the power supply side and the switch connector side of the RPS. NEBS GR-63 recommends that you allow at least 30 in. (76.2 cm) in front of the rack or cabinet and 24 in. (61 cm) behind the rack or cabinet.