Used to replace a 15 amp ground fault circuit in an air RV. I must have inserted the wire incorrectly on the first try; thought that doesn't work. Tried again later and it worked. The wire at the bottom is very thick copper, so it's difficult to route it in between all the other wires in the small space of the RV's junction box. Trimmed some of the twisted wire and that helped. Thank you for finding this hard-to-find item!