Board Thread:Questions and Answers/@comment-198.174.206.226-20130118043125/@comment-5319459-20130118214055

In loss-less mode, the Electric Wrench only uses extra power when the machine would have broken.

When changing modes, you should see text popup in chat saying that is is in normal or loss-less mode.

Also, seeing as you are using Tekkit Lite, I would recomend you invest in a OmniWrench as it is loss-less (and works on all machines).