Printable NEC Reference Cards
Free letter-size PDF quick cards. The reference cards are computed from the same National Electrical Code table data that powers this site's calculators; the seasonal pack is homeowner-facing and works in amps rather than code tables. Print them for the truck, the gang box, the exam-prep binder, or the refrigerator. Every download here is free with no signup and no watermark; the opt-in below is optional, for people who want a heads-up when a new card or tool ships.
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Voltage Drop Max-Run Card
Computed (copper, 3% drop, 120 V single-phase)
Maximum one-way run in feet for a 3% drop, 14 AWG through 500 kcmil at 15-200 A, computed by the same code as this site’s voltage-drop calculator and gated at each conductor’s 75 °C ampacity and the 240.4(D) small-conductor limits. Double the distances for 240 V.
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AWG / kcmil ↔ mm² Conversion Card
AWG-system geometry (ASTM B258)
Circular-mil and mm² cross-sections for every AWG and kcmil size: the numbers behind K-factor voltage-drop math and metric substitutions.
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Holiday Circuit Map + Load Worksheet
9 pages · homeowner-facing · fill-in worksheets
A fill-in circuit map and load worksheet for a house, plus six one-page seasonal safety cards (season opener, Halloween, the Thanksgiving kitchen, the December circuit check, power outage, and an emergency card for the refrigerator). Built for the homeowner side of the seasonal guides, not for the truck: everything is pre-converted to amps against a 12 A or 16 A branch-circuit budget.
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NEC Code Quickstart
The cards above are the quick reference. The book walks all twelve exam calculations start to finish, each with a worked example and the exact code reference: ampacity and derating, breaker sizing, voltage drop, box and conduit fill, grounding, dwelling load, range and dryer demand, motor circuits, and transformer current. Written for the 2023 NEC with notes for the 2026 edition.
About these cards
Each card is computed by the same code that powers this site's calculators; the values are covered by the calculator test suites, and every generated cell is self-checked against the calculator before the PDF is published. These cards are derived reference charts, not reproductions of National Electrical Code tables; NFPA publishes the code itself, and a quick card never replaces the code book. For live derating, fill, and voltage-drop math, use the calculators, and for exam practice built on the same data, take the journeyman practice test, the master practice test, the electrical calculations practice test, or the grounding and bonding practice test.
Results are for reference only. Verify against the applicable adopted edition of the NEC and consult a licensed electrician for code compliance.