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LWC Site Guidelines and Requirements

General Site Guidelines

Efficient device operation requires proper site planning and maintenance. It also requires proper layout of the equipment, rack or cabinet, 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. Ensure 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.

Strong sources of electromagnetic interference (EMI) can cause:

  • 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.

Physical Specifications of an LWC Device

The LWC device chassis is a rigid sheet-metal structure that houses the hardware components. Table 2 summarizes the physical specifications of the LWC chassis.

Table 2: Physical Specifications of the LWC Device Chassis

Product SKU

Height

Width

Depth

Weight

LWC

1.72 in. (4.3 cm)

17.36 in. (44.1 cm)

12 in. (30.5 cm)

9.48 lb (4.3 kg)

Clearance Requirements for Airflow and Hardware Maintenance for an LWC Device

When planning the site for installing an LWC device, you must allow sufficient clearance around the installed chassis (see Figure 1).

Figure 1: Clearance Requirements for Airflow and Hardware Maintenance for an LWC Device Clearance Requirements for Airflow and Hardware Maintenance for an LWC Device
  • For the cooling system to function properly, the airflow around the chassis must be unrestricted. See LWC Cooling Systemfor more information about the airflow through the chassis.

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

  • Leave at least 24 in. (61 cm) both in front of and behind the LWC device. For service personnel to remove and to install hardware components, you must leave adequate space at the front and back of the LWC. 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.

Rack Requirements for an LWC Device

You can mount the LWC 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 3 provides the rack requirements and specifications for the device.

Table 3: Rack Requirements and Specifications for the Device

Rack Requirement

Guidelines

Rack type

Use a two-post rack or a four-post rack. You can mount the device on any two-post or four-post rack that:

  • Provides bracket holes or hole patterns spaced at 1 U (1.75 in. or 4.45 cm) increments.
  • Meets the size and strength requirements to support the weight.

A U is the standard rack unit defined in Cabinets, Racks, Panels, and Associated Equipment (document number EIA-310–D) published by the Electronics Industry Association (http://www.ecianow.org/standards-practices/standards/).

The rack must meet the strength requirements to support the weight of the chassis.

Mounting bracket hole spacing

The holes in the mounting brackets are spaced at 1 U (1.75 in. or 4.45 cm). Therefore, you can mount the device in any rack that provides holes spaced at that distance.

Rack size and strength

  • Ensure that the rack complies with the standard for 19-in. rack as defined in Cabinets, Racks, Panels, and Associated Equipment (document number EIA-310–D) published by the Electronics Industry Association.

  • Ensure that the rack rails are spaced widely enough to accommodate the device chassis' external dimensions of 1.72 in. (4.3 cm) height, 17.36 in. (44.1 cm) width, and 12 in. (30.5 cm) depth. The 19-in. rack brackets have a width of 0.82 in. (2.1 cm) , height of 1.72 in. (4.3 cm), and depth of 2.1 in. (5.4 cm). The 23-in. rack brackets have a width of 3.3 in. (8.4 cm), height of 1.72 in. (4.3 cm), and depth of 8.5 in. (21.6 cm).

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

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

Rack connection to building structure

  • Secure the rack to the building structure.

  • If your geographic area is earthquake-prone, you must secure the rack to the floor.

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

We supply, with each device, one pair of mounting brackets for mounting the device on two posts of a rack . For mounting the device on four posts of a rack or cabinet, you can order a four-post rack-mount kit separately.

Cabinet Requirements for an LWC Device

You can mount the LWC device in an enclosure or cabinet that contains a four-post 19-in. open rack as defined in Cabinets, Racks, Panels, and Associated Equipment (document number EIA-310-D) published by the Electronics Industry Association.

Cabinet requirements consist of:

  • Cabinet size and clearance

  • Cabinet airflow requirements

Table 4 provides the cabinet requirements and specifications for the LWC device.

Table 4: Cabinet Requirements for the LWC Device

Cabinet Requirement

Guidelines

Cabinet size and clearance

The minimum depth of a cabinet for accommodating an LWC device is 36 in. (91.4 cm). Large cabinets improve airflow and reduce the chance of overheating.

Cabinet airflow requirements

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

  • Ensure that the cool air supply you provide through the cabinet adequately dissipates the thermal output of the device (or devices).

  • Ensure that the cabinet allows the chassis hot exhaust air to exit the cabinet without recirculating into the device. An open cabinet (without a top or doors) that employs hot air exhaust extraction from the top allows 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 allows for the proper clearance around the device and cabinet.

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

Requirements for Mounting an LWC Device on a Desktop or Other Level Surface

You can install the LWC device on a desktop or other such level surface by attaching the four rubber feet (provided) to the bottom of the chassis.

When choosing a location, allow at least 6 in. (15.2 cm) of clearance between the front and back of the chassis and adjacent equipment or walls.

Ensure that the desktop or other level surface on which the device is installed is stable and securely supported.