SIPS wiring

The process of wiring a SIP home includes pulling wire through 1 ½" diameter vertical and horizontal chases that are cored through the EPS before the panel lamination process. These chases always extend from edge to edge in both axis.

Horizontal chases are included at the 16" level (for receptacles) and at the 44" level (for wall switches and counter receptacles). Vertical chases allow wire runs vertically through the wall panel to access wall switch locations and at other locations as needed to provide vertical wiring options for the electrician. Layout of chase locations is done at the time the panel layout drawings are made. Once panels are manufactured, chase locations can easily be located, as they are marked with 1" wide lines on the interior OSB surface.

As structural panels are installed, the builder must drill sill and top plates, and 2x connection splines (if used), to provide open chase ways for the electrician. When the electrician comes to the building site, he will review the electrical plan and wire run options to determine which chases to use. Many buildings retain traditionally framed interior walls and floors, which give additional flexibility in wiring. Wiring is simplified if major horizontal wire runs take place in the basement, using horizontal panel chases for local runs only.

When a building has an open ceiling plan, locate lighting, fans, etc. to make wire runs as easy as possible. Wiring can be run from an interior walls or can be run along an exposed overhead beam. Panel chase ways can also be included in roof panels, to allow internal wiring from wall panel to ceiling mounted lighting or fans.

When horizontal wire circuits must continue from one wall to another, intersecting, wall, it is necessary to use vertical chases to exit the wall and then to enter the intersecting wall. Vertical chases are placed near wall intersections to allow for this exiting and entry of wiring.

When no precut panel chase is available, there are various options available:

A 1" wide slot may be cut in the interior OSB skin into which wire can be placed. Because the OSB is structural, there are limits to slot length and location. A slot should not extend all the way to the edge of a panel but should stop 6" short of the edge. A vertical slot should be no longer than 48" and a horizontal slot should be no longer than 12". Wire should be placed deep enough into the EPS to be out of reach of drywall screws. Once wire has been placed in the slot, foam should be applied to fill the opening.

Wiring can also be run behind roof support secondary framing members (see drawing #38-301), baseboards, and moldings.

Commercial flush mounted raceways, such as wire mold can be used.

Conduit which conforms to local code restrictions can be used.

Standard "Romex" type wire, labeled as NM-B, of sufficient wire gauge size as required for the anticipated maximum amperage loading, is recommended for use in panels.

Recommended sequence for wiring is to locate receptacle, switch, and other box locations. Boxes should be offset from the wire chase location so the box will not block the chase following installation. Make the openings in the OSB and EPS necessary to accommodate the boxes, removing only enough insulation to allow box to be installed. Pull wiring required for circuits. Insert the ends of the pulled wire into the boxes and mount the boxes using surface type fasteners.

Once mounted to the OSB, carefully seal around the box using low expansion foam. Use foam sealant to fill both used and unused chases at the top and bottom of panels and wherever chase openings are accessible.

Consult local building and fire codes to see if additional restrictions apply.

Copyright: 07/26/2006