Our Fence Charger Lightning Fuse 5J> are designed to protect against Lightning Strikes to your fence on the Hot or Ground fence. When lightning strikes your fence the 5J> Fuse will blow and not your charger. The 5J> Fuse is designed for the Larger Fence Chargers that are 5-Joule or larger. They are designed to carry a full load from the fence charger when there is a direct ground but will also blow if a lightning strike gets on your fence. Attaches directly to your fence charger or inline with the charger & fence wire. Use on the Ground fence as well if you are running a ground fence along with your Hot fence. Fuses come in packs of two for both Hot & Ground fence.