It is said that walking your Manectric (with a rubber leash, of course; those who use Growlithe leashes soon get their hands zapped through the leash) is the safest place to be during a thunderstorm. This is because Manectric are natural lightning rods, capable of defending their teammates from electric attacks not only in double and triple battles, but in the massive pokemon melees which rocked Hoenn before peace came to the land.
This ability is also the primary reason that Manectric and not Houndoom or Arcanine are used for herding Mareep and Flaaffy. Mareep, contrary to popular belief, are by no means docile and on long migrations are prone to rebel by shocking their trainers. Although humans are remarkably resilient at surviving pokemon attacks, so permanent damage is rare, without a Manectric an unfortunate pastoralist can be left impoverished as his or her entire flock runs away. Furthermore, a Manectric's own current makes Mareep more willing to follow, often luring them like a Magnemite draws metal, which add to their ability to protect farmers and their other pokemon which make them a necessity for anyone bringing these electric sheep on a long journey.
Although Manectric can easily absorb vast amounts of electricity, they are no less capable when it comes to discharging it. And Manectric refuse to absorb the attacks of their own species, perhaps out of solidarity, perhaps simply confusing it for their own. Therefore, the only way to get shocked when a Manectric is around is to get on its bad side, and if you do, you can count on no protection from any others you train.