We initiate the study of k-edge-connected orientations of undirected graphs through edge ips for k 2. We prove that in every orientation of an undirected 2k-edge-connected graph, there exists a sequence of edges such that ipping their directions one by one does not decrease the edge-connectivity, and the final orientation is k-edge-connected. This yields an \edge-ip based"new proof of Nash-Williams' theorem: an undirected graph G has a k-edge-connected orientation if and only if G is 2k-edge-connected. As another consequence of the theorem, we prove that the edge-ip graph of k-edge-connected orientations of an undirected graph G is connected if G is (2k + 2)-edge-connected. This has been known to be true only when k = 1.