Juniper MX2020 Hardware Manual page 120

Figure 35: Three-Phase Delta AC Power Distribution Module
Figure 36 on page 97 shows the three-phase delta 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 clockwise or counter-clockwise will operate correctly.
Figure 36: Three-Phase Delta AC Power Distribution Module Connections
The three-phase delta AC PDM must be installed and secured in the chassis
97