Free Electrical Tools
Professional electrical calculation tools for NEC compliance. All tools are free, accurate, and designed for electricians.
Box Fill CalculatorMost Popular
Calculate electrical box fill per NEC 314.16. The most accurate and easy-to-use box fill calculator online.
Wire Gauge Chart
Complete AWG wire gauge chart with conductor volume allowances per NEC Table 314.16(B).
NEC Code Reference
Quick reference guide for NEC 314.16 electrical box fill requirements and code sections.
Volume Converter
Convert between cubic inches and cubic centimeters for electrical box volume calculations.
Conduit Fill Calculator
Calculate conduit fill percentage per NEC Chapter 9. Supports EMT, IMC, RMC, and PVC conduit.
Gabay sa Pull Box Sizing vs Box Fill
Pinaghihiwalay ang NEC 314.16 box-fill volume mula sa NEC 314.28 length, angle-pull, at U-pull sizing rules.
Voltage Drop and Box Fill Guide
Plan long branch circuits without missing NEC 314.16 box volume, conductor upsizing, device yokes, clamps, and grounding allowances.
Equipment Grounding Conductor Box Fill Guide
NEC 314.16(B)(5) examples for counting ground wires, bonding jumpers, pigtails, and mixed-size grounding conductors in boxes.
Guía de llenado de cajas para protector contra sobretensiones SPD
Dimensione cajas SPD con NEC 314.16, NEC 242, puesta a tierra, longitud de conductores, abrazaderas internas y contexto IEC.
GFCI Receptacle Box Fill Guide
NEC 314.16 examples for GFCI outlet boxes with line/load conductors, device yokes, pigtails, grounds, and clamps.
USB-C Receptacle Box Fill Guide
Laki ng USB-C, USB-A, at mga kumbinasyong receptacle box na may mga halimbawa ng NEC 314.16 device-yoke, grounding, clamp, at conductor-count.
Gabay sa box fill para sa terminal block
Mga halimbawa ng NEC 2023 para sa terminal block, bilang ng conductor, grounding, clamp, at praktikal na laki ng kahon.
Gabay sa box fill para sa multi-wire branch circuit
Gamitin ito kapag ang shared-neutral circuit ay pumapasok sa junction box, switch box, o receptacle box at kailangang pumasa sa NEC 314.16.
Dishwasher and Disposal Box Fill Guide
NEC 314.16 examples for dishwasher junction boxes, disposal switch boxes, GFCI receptacles, grounds, clamps, and 12 AWG kitchen wiring.
Smart Switch Box Fill Guide
Worked NEC box-fill examples for smart switches, neutral bundles, travelers, pigtails, and deep electronic controls.
Gabay sa box fill ng motor disconnect
Size na motor disconnect, pump-control, at mga motor junction box na may NEC 314.16, NEC 430, grounding, clamps, at IEC enclosure-space checks.
Gabay sa Box Fill ng EV Charger
Worked box-fill examples for NEMA 14-50 outlets, hardwired EVSE wallboxes, 40 A and 60 A charging circuits, and outdoor charger junctions.
Gabay sa box fill para sa wire connectors
Mga halimbawa ng NEC 314.16 para sa wire nuts, lever connectors, splice bundles, pigtails, at praktikal na volume ng kahon
Frequency Table Calculator
Quick electrical frequency table for 50 Hz, 60 Hz, generator output, VFD output, and field compatibility checks.
Box Fill Chart
Quick chart for common electrical box sizes, conductor-only capacity, and practical box choices before you run the exact NEC calculation.
Box Fill Calculator PDF
Download a printable NEC 314.16 worksheet PDF for field counts, rough-in notes, and final box-volume checks.
Gabay sa Pagpuno ng Kahon ng Ceiling Fan
Mga ginamit na halimbawa para sa mga kahon ng kisame na may rating na fan, mga kabit ng suporta, at bilang ng konduktor sa ilalim ng NEC 314.16 at NEC 314.27.
Banyo na Fan at Gabay sa Pagpuno ng Light Box
Sukat ng bathroom fan, ilaw, timer, humidity-control, at heater switch box na may NEC 314.16 conductor counts.
Gabay sa Pagpuno ng Aluminum Wire Box
Nagtrabahong mga halimbawa ng box-fill para sa aluminum branch circuit, receptacle repair, feeder splice, at NEC 110.14 / 314.16 checks.
Gabay sa Pagpuno ng Kahon na hindi tinatablan ng panahon
Nagtrabahong mga halimbawa ng box-fill para sa mga panlabas na GFCI receptacles, weatherproof switch, pump circuit, at wet-location junction box.
Gabay sa Pagpuno ng Extension Ring at Box Extender
Mga gumaganang halimbawa para sa mga nakalistang extension ring, box extender, mud ring, at kapag mas malaking box ang tanging ligtas na sagot.
Gabay sa Box Fill para sa Neutral at Pigtail
Mga halimbawa ng NEC 314.16 para sa neutral, shared neutral, pigtail, smart switch, at multi-gang box.
Multi-Gang Switch Box Fill Guide
Worked box-fill examples for 2-gang and 3-gang switch boxes, dimmers, smart switches, and crowded remodel layouts.
Gabay sa Mini-Split Disconnect
Payo sa box fill at enclosure sizing para sa mini-split disconnect-adjacent box, whip transition, at upsized na HVAC conductor.
Gabay sa Pagpasok ng Generator
Payo sa box fill at enclosure sizing para sa portable generator inlet box, transfer-adjacent splice, at mas malalaking backup-power conductor.
Gabay sa Pampainit ng Tubig
Payo sa pagpapalaki ng box fill at enclosure para sa mga storage water heater, tankless circuit, disconnect-adjacent box, at mas malalaking branch-circuit conductor.
Gabay sa Pagpuno ng Kahon ng Solar Disconnect
Nagtrabahong mga halimbawa ng box-fill para sa PV AC disconnects, rapid-shutdown junctions, inverter transition, at upsized solar feeder conductors.
Essential Electrical Calculation Tools
Our suite of free electrical tools helps electricians, contractors, and engineers perform accurate calculations for NEC compliance.
Why Use Our Electrical Tools?
- NEC NEC Compliant: All calculations follow current National Electrical Code requirements
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- Regularly Updated: Updated for NEC 2023 including terminal block requirements