When we are behind proxy some times bower install gives error as :

retry Request to https://bower.herokuapp.com/packages/angular failed with ECONNRESET, retrying in 1.2s

Then we have to update .bowerrc file(which is in root direcory)with below proxy configuration:

{
  "directory": "app/bower_components",
  "registry": "http://bower.herokuapp.com",
  "proxy":"http://proxy-name:port-number/",
  "https-proxy":"http:/proxy-name:port-number/",
  "strict-ssl": false
}

Dont miss the https-proxy.I missed it once and i was unable to download some dependent repos of bower.After this you can happily go with your bower install