EX Series Switch Software Features Overview
Understanding Power Management on EX Series Switches
Configuring Power Supply Redundancy (CLI Procedure)
Configuring the Power Priority of Line Cards (CLI Procedure)
[edit chassis] Configuration Statement Hierarchy
chassis
fpc
n-plus-n
power-budget-priority
psu
redundancy (Power Management)
Verifying Power Configuration and Use
show chassis power-budget-statistics
http://kb.juniper.net/