The installation of wiring is one of the first concerns people have with structural insulated panels (SIPs), but the reality of the challenge isn’t a big problem. The best way to install wires is by stringing them through floor and ceiling frames, then running the cables down slots routed through the interior surface of the OSB. Cut a plywood template to guide the travel of the router, speeding the operation. Vertical cuts in the OSB are completely acceptable and don’t interfere with wall integrity. Just be sure to avoid horizontal cuts since they greatly reduce panel strength. Extend the slots to 2” deep using a hot knife to remove foam, then install wiring and electrical boxes. Apply foam to the wire slots after inspection, then install interior wall surfaces.