Cisco CISCO7204, Руководство по нормативному соответствию и безопасности, Страница: 11 / 38

11
Port Adapters
Installation Requirements
This section describes special installation requirements for the HSSI port adapters.
Where applicable, the HSSI port adapters are approved only for installation in a host and with host
attachments, which are either type approved for such apparatus or covered by a General Approval.
Except at the edge connector, which plugs into the router’s midplane, clearance and creepage
distances of X millimeters (mm) and Y mm, as listed in Table 2, must be maintained between the
HSSI port adapters and other parts of the host, including any other port adapters.
Creepage distance is defined as the minimum distance between two points (following the contour of
the insulator) measured across the surface of an insulator. Clearance distance is defined as the
minimum distance between two points (line of sight) measured in air.
Table 2 Creepage and Clearance Distances Based on Voltage
Clearance and creepage distances are measured between adjacent parts, as shown in Figure 7.
Figure 7 Creepage and Clearance Distance Measurements
1. Vrms = root mean square voltage.
2. VDC = volts direct current.
3. The creepage distances not in parentheses apply when the equipment is installed in a normal office environment. The larger
dimensions, given in parentheses, must be applied when the equipment is installed in an environment in which dust and other
types of pollution could conduct electricity because of the effects of dampness and condensation. This applies to locations
subject to high humidity.
4. For working voltages exceeding 300V, consult a competent telecommunications engineer prior to installation.
Voltage Used or Generated by Other Parts
of the Host or Expansion Card (Vrms
1
or VDC
2
) Creepage (Y mm)
3
Clearance (X mm)
Up to 50 2.4 (3.8) 2.0
Up to 125 3.0 (4.8) 2.6
Up to 250 5.0 (8.0) 4.0
Up to 300
4
6.4 (10.0) 4.0
Communication module
Carrier card Expansion card
X X
Y
Y
Power supply unit
or other source of
excessive voltage
H2793