As you continue building your SIP envelope, it’s important to stay in close communication with your plumber and electrician. Premier SIPs come from the factory with pre-installed, factory-cut electrical chases, so it’s critical to review their locations early and discuss how you want to run wiring throughout the structure.
The blue lines on the shop drawings represent these chases. Vertical chases are typically placed every four feet on center, while horizontal chases are set at standard switch and outlet heights. Vertical and horizontal chases are interconnected at the center of each panel, allowing wiring to transition between vertical and horizontal runs depending on where your switches and plugs need to be.
For more detailed guidance, Premier also provides an instructional video on electrical wiring in SIPs.
Wiring SIPs: Step-by-Step
Premier SIPs are factory-prepared with vertical and horizontal electrical chases in the foam core. When installing SIP walls:
Begin by setting the bottom plate on the platform or subfloor, ensuring the SIP’s outer face is fully supported.
Review the SIP layout drawings carefully to locate the vertical electrical chases.
Mark the vertical chase locations on both the subfloor and the bottom plate.
Using a boring spade or similar drill bit slightly larger than the factory chase, drill vertical holes completely through the bottom plate and subfloor sheathing.
As you stand the SIP panels, align the vertical chases with your drilled access holes. If adjustments are needed, remark and re-drill accordingly.
When using block splines or solid/engineered lumber splines, pre-drill holes to align with the horizontal electrical chases.
At the top of the wall, drill vertical holes through the top plate at chase locations, maintaining a clear path for wiring.
Marking and Cutting for Electrical Boxes
At factory-marked switch and receptacle heights, use an electrical box as a template to mark the SIP surface.
Use a circular saw to make access cuts at chase intersections where wiring needs to change direction.
Using a rotary cutter, cut out the entire marked area for switch and receptacle boxes.
Retain the cutout pieces; they can be reused to patch any unwanted openings later.
Make sure all drilled access holes and chase paths are clean and free of debris to ease wire pulling.
Running Wire in SIP Walls After cutting the openings:
Wire can be pulled easily through the interconnected chases.
Once wiring is installed, mount all switch, receptacle, and fixture boxes.
Wiring Corners in SIP Walls Two options exist for turning corners with wiring:
Direct the wire downward into the floor platform from one vertical chase and feed it upward through the chase of the adjacent wall.
Alternatively, cut a 4" circular hole at the height of the horizontal chase in the exterior corner, feed the wire through, and then replace and foam the circular plug afterward.
Air Sealing After Wiring
Use low-expanding construction foam to seal behind all electrical boxes and in all unused cutouts.
Foam seal all wire access holes, both used and unused, for maximum air tightness.
Wiring SIPs in Different Foundation Types
Structural Floor Platforms: Wiring access is from the floor platform below.
Stem Wall or Basement Foundations: SIPs sit on the mud sill with wiring accessed from the subfloor.
Two-Story SIP Construction: Align second-story bottom plate chases with first-story wiring chases.
Slab-on-Grade Foundations: Wiring enters from the top of the SIP wall or through intersecting partition walls.
Every platform configuration provides different but accessible paths for wiring SIP structures.
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