Juniper MX2020 Hardware Manual page 122

NOTE: The three-phase wye AC PDM terminal blocks will be flipped depending on which slot
the PDM gets plugged into.
Figure 38: Three-Phase Wye AC Power Distribution Module
Figure 39 on page 100 shows the three-phase wye AC PDM connections.
CAUTION:
before connecting the power input cables. If the PDM must be removed, both input
power cables must be uninstalled and removed from the PDM before the PDM can
be removed from the chassis. The MX Series chassis is not sensitive to phase rotation
sequence—either CW or CCW will operate correctly.
The three-phase wye AC PDM must be installed and secured in the chassis
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