Conduit, Box Fill & Thermal Mechanics Calculators
Engineering utilities for physical electrical installation: raceway fill limits, junction box cubic-inch volume allowances, equipment cabinet thermal dissipation, and cable pulling jam hazard detection.
Raceways
Conduit Fill Sizing Calculator
Calculate raceway fill percentage and minimum trade size for mixed wire gauges across EMT, PVC 40/80, and Liquidtight under the NEC 40% rule.
Box Volume
Junction Box Volume Allowance Sizer
Sizes electrical junction boxes under NEC 314.16 accounting for conductor volume, internal clamps, switches, receptacles, and grounds.
Cabinet Cooling
Cabinet Heat Dissipation & Fan CFM Sizer
Calculates thermal wattage from inverters, MPPTs, and DC-DC chargers sealed inside van/boat cabinets and sizes required cooling fan CFM.
Pulling Safety
Conduit Jam Ratio & Pulling Tension Sizer
Detects the dangerous 2.8 to 3.2 jam ratio danger zone where 3 cables wedge in bends and calculates cable pulling friction across sweeps.
Physical Raceway & Enclosure Engineering
Electrical safety requires more than proper wire gauge and circuit breakers. Physical raceways and enclosures must manage heat accumulation and mechanical stresses:
- Thermal Derating in Raceways: Bundling multiple conductors inside conduit concentrates heat. When 4 or more current-carrying conductors share a raceway, their ampacity must be derated by 80% to 50% (NEC 310.15(C)(1)).
- Box Crowding Hazards: Overfilling junction boxes leads to damaged conductor insulation when devices are screwed into the box, causing ground faults and potential electrical fires.
- Cabinet Heat Traps: Sealing high-power equipment inside unventilated wooden van benches or engine spaces leads to premature equipment failure. Proper cross-flow airflow prevents expensive thermal shutdowns.