viii 90453-02 Rev A0
To maintain the independent approval of the X.21 board, it is essential that, when other
option boards are introduced that use or generate a hazardous voltage, the minimum
creepages and clearances specified in the table below are maintained. A hazardous voltage
is one that exceeds 42.4V peak a.c. or 60V d.c. If you are in doubt, seek the advice of a
competent engineer.
Clearance (mm) Creepage (mm)
Voltage Used or Generated by
Host or Other Boards
2.0 2.4 (3.8) Up to 50 V
rms
or V
dc
2.6 3.0 (4.8) Up to 125 V
rms
or V
dc
4.0 5.0 (8.0) Up to 250 V
rms
or V
dc
4.0 6.4 (10.0) Up to 300 V
rms
or V
dc
For a host or other expansion board fitted in the
host, using or generating voltages
greater than
300V (rms or dc), advice from a competent tele-
communications safety engineer must be obtained
before installation of the relevant equipment.
Above 300 V
rms
or V
dc
Book Page viii Thursday, March 27, 1997 10:55 AM
To Next Page
Loading...