[Ed. Note] In TLS#49, one method of placing electrical boxes was shown. Code regulations vary widely and other methods may be required. Here’s one option that meets code in Colorado.
Help yourself or your electrician by placing your choice of blue smurf (plastic tubing), metal conduit, underground wire, or just bare Romex wire deep into the joints of the straw bales or by making a channel with a chainsaw on the face of the bale. According to the Colorado State Electrical Board, the Romex wire cannot be exposed to the stucco. Keep the wire deep enough so that when hanging your favorite painting on the wall you will not hit the wire with your anchor. You can put a little fiberglass insulation over the Romex and then add strips of lath or stucco netting over that to keep it in place. Be careful not to knick the protective coating of the wire when placing the pins into the straw.
With a chainsaw, clean out a square spot for the box a couple of inches deep. To the right of the square divot, push the chainsaw into the straw straight and level about 12 to 14 inches deep. This is for a piece of plywood or OSB, 8 to 12 inches long, the height of the box. Cut the end of the plywood to a triangular point that will drive into the bale. Nail the plastic blue electrical box 5/8-inch from the edge of the plywood, run your Romex into the box 10 inches and, with red duct tape, tape up the rest of the extra holes. On the front of the box with red duct tape, tape just to the edge of the box, not around the sides. It will get buried in the plaster and may cause empty voids. Place a long nail or a screw in the center of the red tape so it is out an inch or so. This will make it easier to find the box if it gets buried. Also, it would be helpful to spray paint a dot below each box on the unfinished floor to help find the box in case it gets buried really deep under the plaster.
Staple a little roofing felt over the plywood then stuff any voids around the box with loose straw. Again, be careful when placing your pins into the straw and putting your lath around the box so that you do not knick a wire. Keep the box square and plumb when lathing and out from the face of the straw 3/4-inch to 1-inch. While the first coat of plaster is still wet, go around and check the boxes to make sure they are still square and plumb. Pull the plaster back 1/2-inch from the rim for the next coats. Before the finish coat, finish out the box with the face plate. Cover the plate with blue painter’s tape to the edge. Bring the finish coat up to the edge of the cover. If the face plate is too far out, bring joint compound filler or the finish coat up to the edge and behind the cover. Now those electrical boxes will look great!  

Tony Caniglia, Affordable Housing Authority, L.L.C. , PO Box 275, Jefferson, Colorado  80456; 303.905.4282  mobile,  www.strawbaleconstruction.com.