A Scott Wagstaff strike and a Johnnie Jackson penalty put the Addicks in control but second-half strikes from substitute Paul Heffernan and new signing Reda Johnson drew the Owls level.
Wednesday also blew a chance when Johnson was pushed by Gary Doherty in the area in the 38th minute but keeper Rob Elliot dived full length to keep out Tommy Miller's penalty.
Peacock said of Powell's appointment: "He's a tremendous choice of manager. He was very popular as a player at Charlton and whatever he's done he's done well and professionally.
"Every manager must be given a chance and when I worked with Chris as a player, I thought that whatever route he chose he would be successful.
"His England call-up in his 30s shows you what he's about - long term, he gets there. This is not a flash, fly-by night situation."