A structure includes a galvanic isolation including a horizontal portion including a first redistribution layer (RDL) electrode in a first insulator layer, and a second RDL electrode in the first insulator layer laterally spaced from the first RDL electrode. An isolation break includes a trench defined in the first insulator layer between the first RDL electrode and the second RDL electrode, and at least one second insulator layer in the trench. The first insulator layer and the second insulator layer(s) are between the first RDL electrode and the second RDL electrode. The isolation may separate, for example, voltage domains having different voltage levels. A related method is also disclosed. The isolation may also include a vertical portion using the first RDL electrode and another electrode in a metal layer separated from the first RDL electrode by a plurality of interconnect dielectric layers.