If you haven't put the access pipes for the electric wire and plumbing through the foundation, make sure you set them on top of the foundation and cob them in place. If you haven't decided exactly where the access pipes should go, just put in extra ones and fill the ones you don't need later with cob. (See more about this in the chapter on foundations, page 43.)
Because cob is completely fire proof, electric wires can be buried right into the cob walls or put in conduit pipes and buried in as you build. Bury them at least an inch deep in the wall to avoid chopping into the wires later when you do the final shaping of the walls. Mark where the wires are buried in the cob so you can find them in the future.
To hold the electric receptacle boxes in the cob, get a piece of wood a little bigger than the box, and nail or screw it to the back of the box. Cob it in where you want it. If you'd rather deal with finishing the electricity later, leave a hole and, when you get to it, embed the box into the hole with cob.
Another approach to installing the electric wires is to carve a groove out
of the cob where you want the wires to be, either when it's wet or dry. Lay
the wiring in the grooves after you've finished the walls and just fill the
groove with cob or plaster afterwards.