Technical Documentation

Cabinet size and clearance

• The minimum cabinet size for accommodating an EX8208 switch is 23.62 in. (60 cm) wide and 30.0 in. (76.2 cm) deep. Large cabinets improve airflow and reduce the chance of overheating. To accommodate a single EX8208 switch in a four-post rack, the cabinet must be at least 14 U high (or 15 U if you install the power cord tray, which is optional for the four-post rack). To accommodate a single EX8208 switch in a two-post rack, the cabinet must be at least 15 U high.

  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.eia.org).

• With adequate cooling air and airflow clearance, you can stack three EX8208 switches in a cabinet with a four-post rack that has at least 42 U of usable vertical space. (45 U are required if you install the optional power cord tray.) You can stack three EX8208 switches in a cabinet with a two-post rack that has at least 45 U of usable vertical space (for two-post rack installations, installing the power cord tray is mandatory). In all cases, the rack must meet the strength requirements to support the weight.
• The minimum total clearance inside the cabinet is 29.2 in. (74.17 cm) between the inside of the front door and the inside of the rear door.

Cabinet airflow requirements

When you mount the switch on a cabinet, ensure that ventilation through the cabinet is sufficient to prevent overheating. Consider the following requirements list when planning for chassis cooling:

• Ensure that the cool air supply you provide through the cabinet adequately dissipates the thermal output of the switch (or switches).
• Ensure that the cabinet allows the chassis hot exhaust air to exit the cabinet without recirculating into the switch. 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. For an illustration of chassis airflow, see Clearance Requirements for Airflow and Hardware Maintenance for an EX8208 Switch.
• The switch fans exhaust hot air through the right side of the chassis (the left side when you face the front of the chassis, where the fan tray slides in). Install the switch in the cabinet in a way that maximizes the open space on the fan tray side of the chassis. This maximizes the clearance for critical airflow.
• Route and dress all cables to minimize the blockage of airflow to and from the chassis.
• Ensure that the spacing of rails and adjacent racks allows for the proper clearance around the switch and rack as specified in Clearance Requirements for Airflow and Hardware Maintenance for an EX8208 Switch.