Waya wotsekeredwa katatu kapena waya wokhazikika wokhazikika womwe umapangidwa ndi zigawo zitatu, umatsekereza choyambira kuchokera kuchiwiri kwa thiransifoma.Kutsekereza kolimbikitsidwa kumapereka miyezo yosiyanasiyana yachitetezo yomwe imachotsa zotchinga, matepi apakati ndi machubu otsekera mu thiransifoma.
Ubwino kwambiri wa katatu insulated waya si apamwamba kuwonongeka voteji kuti ndi 17KV, koma Kuwonjezera kuchepetsa kukula ndi chuma ndalama zakuthupi kupanga thiransifoma.