Guide me through the steps to cut and install continuous insulation panels around an electrical service panel.

To install continuous insulation panels around an electrical service panel, measure the enclosure dimensions, cut the expanded polystyrene panels using a utility knife or handsaw, adhere them flush around the perimeter, and seal all cut edges with low-expansion spray foam.

Electrical breaker panels mounted directly to concrete or masonry basement walls create severe thermal bridges and air leaks that cause condensation behind the enclosure. National Electrical Code (NEC) Article 110.26 requires maintaining a clear working space 30 inches wide and 36 inches deep in front of the panel, meaning insulation must terminate cleanly around the backboard or enclosure rather than encasing it.

If you only do one thing: Maintain a continuous 1/4-inch expansion gap between the insulation foam and the service panel casing, filling it with fire-rated expanding foam to eliminate air bypass without crowding electrical knockouts.

1. Map and establish code clearances: Measure the electrical panel perimeter and verify National Electrical Code working clearances of 30 inches wide, 36 inches deep, and 78 inches high before dry-fitting panels to ensure no insulation infringes on panel door swing or dead-front access.
2. Scribe panel dimensions onto insulation: Transfer the outer cabinet measurements onto the InSoFast continuous insulation panels (which provide R-4.2 per inch of expanded polystyrene), marking where integrated polypropylene studs run to ensure vertical stud continuity remains within 16 inches on center of adjacent framing.
3. Execute clean foam cuts: Cut through the 2.0-inch or 2.5-inch expanded polystyrene (EPS) foam using a snap-blade utility knife along a straightedge, and use a handsaw to slice through the embedded polypropylene studs at a 90-degree angle to match the panel backboard profile.
4. Anchor surrounding insulation to the substrate: Apply continuous 3/8-inch vertical beads of construction adhesive along the back stud flanges of the cut panels, then press them firmly against the concrete or masonry wall tight against the panel borders.
5. Route incoming and branch circuits: Guide Romex or conduit into the panel through the built-in 1-1/2-inch electrical raceways, carving shallow access channels in the foam with a hot-knife tool where lines branch into panel knockouts.
6. Air seal perimeter seams: Inject low-expansion, fire-block polyurethane spray foam into the 1/4-inch joint between the cut insulation edges and the electrical backboard, trimming excess flush after a 60-minute cure time.

• Watch out for: Encasing live branch conductors tightly inside non-breathable foam within 2 inches of the panel knockouts, which can trap heat and violate conductor ampacity derating standards.
• Watch out for: Fastening drywall directly over electrical conduits running through raceways; always install 1/16-inch thick steel nail plates over studs where wires pass within 1-1/4 inches of the finished face.
• Watch out for: Fastening panel framing blindly into concrete within 6 inches of the electrical enclosure, which risks puncturing hidden sub-slab grounding electrode conductors or service lateral feeds.

Measure the clearance depth from the wall face to the front edge of your electrical panel cabinet, then select either 2.0-inch (R-8.5) or 2.5-inch (R-10) panel thicknesses so finished drywall sits flush with the panel trim; consult a licensed electrician for specific local code requirements.