I spoke to Premier about this and they said you can't use a positive ground / neg lead on your own rig.
BUT if you are like me and don't need electric to run your rig and can disconnect the electrial system from the rig you can do what ever you please.
I was also told that using a positive electrode still does a good job because they use a high frequency DC that helps.
I have yet to try it so I can't comment.
