They are using “Implosive Connectors” to make power line connections on the new towers along I-94 in Minnesota. A small explosive charge is evenly distributed around an aluminum sleeve and when it is detonated it uniformly compresses the sleeve down onto the cable inside.
How cool is that? And they don’t want you to watch? oh come on, it is like a frikkin James Bond movie along the interstate!
I never did see any helicopters on the day I drove by, but the company does have a video of the process, and other helicopter line work on their website :