Hello,
i used the electricity method (octet method) to cast out earthworms for my master thesis a couple of month ago. As you can see it looks a bit different. The needels are about 50 cm (19,69 in) deep into the soil and the electricity circles around always on two opponent needels.
I think this method works best with earthworms living on or near the surface. The deep digging species often escape to the subsoil.
Florian