Running electrical service lines in a straw bale house is different than installing electrical work in a conventional house for obvious reasons. Remember that all of the wiring will be buried in the walls behind your beautiful finish plaster, so make sure you get it right the first time.
Timing is everything in construction. If you call for a subcontractor and are not ready for them when they arrive, you will very quickly find yourself on the bottom of their “return call” list. Your electrician will have to make a number of visits to the house, especially if you pour a concrete slab floor. In that case, they will need to rough in their work after the forms are up, but before the concrete is poured.
After the rough-in below the slab, the electricians will need to return and finish the rough-in above the slab. For this, the house needs to be “dried in,” in other words, the roof needs to be on and the windows and doors installed. Unlike conventional construction where the electrical wiring is installed before the insulation, do not call the electricians without having the bales in place. The wiring is best installed directly in the bales after they have been stacked, tamped, and trimmed but before they have been meshed. If you plan on creating niches in the face of the bales, it is good practice to cut those in before the electricians run their wires. If you are on a tight schedule and cannot complete the niche prior to the electrician’s arrival, be sure to spray paint their locations on the bales so the electricians know to avoid those areas with the wires. It’s also a good idea to use paint to predetermine wire and appliance locations to simplify their installation.
Anchoring the electrical boxes to the bale walls is important and quite simple. If the boxes are not adequately anchored in place, they may twist out of plumb during the application of plaster. Once the boxes are knocked out of place and the plaster has hardened around them, they are difficult to fix and a “home made” look will pervade throughout the house. For years, electrical boxes were anchored to the bales with wood spikes as shown in the above picture; however, I have recently started using plywood plates for a faster, safer, and easier installation as shown in the picture to the right. Note the plywood is covered with roofing felt to protect the plaster and is then stapled to the mesh which locks it into place. Finally, a layer of plaster lath is installed to support the plaster over the span of the plate.
I strongly recommend that once you have completed your electrical work and you are ready to plaster that you take the time to mark out the electrical runs with bright paint and then photograph each wall. This will give you a clear map of electrical wire locations should you ever decide to cut into the wall or alter it in any way. One final note, as you can see from the spray painted lines on this wall section, it is important to run your electrical lines vertically and horizontally and no other direction. Do not angle lines to make a run shorter. It may look obvious while the wall is not plastered; however, as soon as the wires are hidden, it is really good to know that all of your wiring is running one of two possible directions. This keeps future owners and electricians much safer should they engage in renovations or alterations to the walls.