Remove/Replace Power Supply blank for HP ProLiant DL380 G5 Server

[chi3]

Dear Expert,

I have read the following link regarding Remove/Replace Power Supply blank for HP ProLiant DL380 G5 Server:-

http://h20564.www2.hp.com/hpsc/doc/public/display?docId=emr_na-c01876133

I would like to know if  the server need to be power down and the existing power supplies of the server need to disconnect the power cord from the server before removing/replacing the power supply blank.  If not, is there any the risk of the electric shock?

Thank you for your kind assistance.