electrician.wiki

Sources and editions

The standards, editions and documents behind our calculations. Each calculator also lists the sections it relies on under its result.

Standards and codes

NFPA 70, National Electrical Code
2026, 2023, 2020 and 2017 editions. Sections are cited by number; no code text is reproduced. NFPA offers free online read-only access to its codes.
IEC 60364-5-52:2009 + COR:2011
Low-voltage electrical installations: selection and erection of wiring systems (current-carrying capacities, correction factors, voltage drop in Annex G).
IEC 60364-4-41, 4-43 and 5-54
Protection against electric shock, protection against overcurrent, earthing arrangements and protective conductors.
BS 7671:2018+A4:2026, the IET Wiring Regulations
Requirements for Electrical Installations, 18th edition, current version Amendment 4:2026 (A2:2022 and A3:2024 withdrawn on 15 October 2026). Cable ratings and voltage drop from Appendix 4; recommended voltage-drop limits from Appendix 4 section 6.4. Our table data was compiled against A2 and A3 and is being re-checked against A4.
IEC 60909-0
Short-circuit currents in three-phase AC systems (voltage factors c).
IEC 60228
Conductors of insulated cables (nominal sizes and maximum DC resistance).
IEC 60062 and IEC 60063
Marking codes for resistors and capacitors; preferred number series (E-series).

How data is sourced

Every table in our engine records where each value came from and when it was checked. A value goes live only when two independent sources agree; values with a single source are either refused or shown with a warning under the result. Code values are used as facts with their table or section cited; we do not reproduce the text or layout of copyrighted codes, and we cite but do not link third-party reprints of code tables. Below are the 254 source records behind our data, grouped by topic. See also our methodology, the published test cases and the sources listed on the NEC adoption tracker.

NEC conductor, raceway and grounding data

Conductor properties, ampacity, AC impedance, raceway and conductor areas, box fill and grounding conductor sizes, checked against at least two independent sources and NFPA’s own revision documents for each edition.

Conductor properties and resistance (7)
  1. NFPA 70-2017 Chapter 9 tables excerpt (third-party course-hosted copy; read for values only, do not link publicly)Primary transcription of every Table 8 value (2017 edition)
  2. NECA-IBEW Electricians, "Tables of NEC" (2011 NEC reprint: Ch. 9 Tables 4, 5, 5A, 8; Tables 310.15(B)(7), 310.15(B)(16), 310.15(B)(3)(a), 314.16(A), 250.66, 250.122)Independent second copy of every Table 8 value (2011 edition); 435 values compared position by position, 0 mismatches
  3. NFPA 70 A2022 cycle (2023 NEC) CMP-6 First Draft ballot: FR-8336 310.15 (Tables 310.15(B)(1)(1), (B)(1)(2), (C)(1), rooftop 19 mm); FR-8602 Ch. 9 Table 8; FR-8374 310.12 / Table 310.12(A)2023 confirmation of sizes, cmil, mm2, diameters, areas and uncoated-copper resistance (FR-8602 Table 8 text)
  4. NFPA 70 A2025 cycle (2026 NEC) CMP-6 First Draft: FR-8036 Tables 310.16/310.17 (2023 base values; XHWN removed from 90 C), FR-7943/7953/8031 310.12, FR-7961 rooftop, FR-8033 adjustment tableScreened for 2026 changes to Table 8 (none)
  5. NFPA 70 A2025 cycle (2026 NEC) CMP-8 First Draft: FR-7763 Ch. 9 Table 1 notes; FR-7525/7527/7529 314.16 (Table 314.16(B)(1) values shown)2026 Table 1 Note 8 wording (bare conductors use Table 8)
  6. Electrical Knowhow, "Voltage Drop Calculations - Part Three" (explainer of NEC Ch. 9 Tables 8 and 9 incl. note data)Third (secondary) check of the Table 8 note data: alpha 0.00323/0.00330, IACS 100/61, compact 9 percent, compressed 3 percent
  7. NFPA issued TIAs (20-1..20-12, 23-1..23-20, 26-1..26-12) and errata (70-20-1..6, 70-23-1..10, 70-26-1..2): screened, none change these tablesScreened: no TIA or errata touches Table 8 in 2020/2023/2026
AC resistance and reactance (6)
  1. NFPA 70-2017 Chapter 9 tables excerpt (third-party course-hosted copy; read for values only, do not link publicly)Primary transcription of every Table 9 value (2017 edition)
  2. electrician2.com, Ch. 9 Table 9 reprint from the 2007 California Electrical Code (= 2005 NEC), pages 1 and 2Independent reprint (2005-era): 280 per-kft values machine-compared plus the 14 AWG row by eye; 0 mismatches
  3. Electrical Knowhow, "Voltage Drop Calculations - Part Three" (explainer of NEC Ch. 9 Tables 8 and 9 incl. note data)Secondary description of the Table 9 basis and the effective-Z formula
  4. NFPA 70 A2022 cycle (2023 NEC) CMP-6 First Draft ballot: FR-8336 310.15 (Tables 310.15(B)(1)(1), (B)(1)(2), (C)(1), rooftop 19 mm); FR-8602 Ch. 9 Table 8; FR-8374 310.12 / Table 310.12(A)Screened for 2023 revisions (none to Table 9)
  5. NFPA 70 A2025 cycle (2026 NEC) CMP-6 First Draft: FR-8036 Tables 310.16/310.17 (2023 base values; XHWN removed from 90 C), FR-7943/7953/8031 310.12, FR-7961 rooftop, FR-8033 adjustment tableScreened for 2026 revisions (none to Table 9)
  6. NFPA issued TIAs (20-1..20-12, 23-1..23-20, 26-1..26-12) and errata (70-20-1..6, 70-23-1..10, 70-26-1..2): screened, none change these tablesScreened: no TIA or errata touches Table 9
Insulated conductor areas (9)
  1. NFPA 70-2017 Chapter 9 tables excerpt (third-party course-hosted copy; read for values only, do not link publicly)Primary transcription of Table 5 and Table 5A (2017 edition)
  2. Conduit.site data file, Ch. 9 Table 5 and Table 5A conductor areas ("Based on the 2020 NEC", with page refs)Independent transcription of Table 5/5A areas (2020 edition); 0 mismatches
  3. Encore Wire, Raceway Fill Calculator (embedded Ch. 9 Table 4 total areas for 9 raceway types; Table 5 and 5A areas)Manufacturer copy of THHN, XHHW and RHH/RHW-2 (with covering) areas and compact Al areas; 0 mismatches
  4. PDHonline Course E276 Conduit Fill Tables (2026): EMT, IMC, RMC, PVC-40, PVC-80 dimensions; THHN, THHW, XHHW 14 AWG-500 kcmil dimensionsTHHN, XHHW and TW/THHW diameters and areas 14 AWG-500 kcmil; 0 mismatches
  5. ICC publication sample 8950P229 (reprint of Ch. 9 Table 5 and part of Table 5A)Reprint of Table 5 and part of 5A; all pairs found except two ICC typos (see NOTES.md)
  6. NECA-IBEW Electricians, "Tables of NEC" (2011 NEC reprint: Ch. 9 Tables 4, 5, 5A, 8; Tables 310.15(B)(7), 310.15(B)(16), 310.15(B)(3)(a), 314.16(A), 250.66, 250.122)Table 5A all columns (2011 edition) - primary row source for 5A, 0 mismatches vs 2017
  7. NFPA 70 A2019 cycle (2020 NEC) CMP-6 First Draft: FR-8331 Ch. 9 Table 5A (footnotes only)2020 Table 5A revision was footnotes only
  8. NFPA 70 A2025 cycle (2026 NEC) CMP-8 First Draft: FR-7763 Ch. 9 Table 1 notes; FR-7525/7527/7529 314.16 (Table 314.16(B)(1) values shown)2026 Table 1 notes (Table 5 worst-case basis) and screening for Table 5 changes
  9. IAEI Magazine, "The Reorganization of NEC Article 310" (Jul-Aug 2021)XHHN/XHWN/XHWN-2 added to ampacity tables in 2020 (context for NOT_IN_TABLE5)
Raceway dimensions (11)
  1. NFPA 70-2017 Chapter 9 tables excerpt (third-party course-hosted copy; read for values only, do not link publicly)Primary transcription of Table 4 (all 13 raceway types, in and mm) and Table 1
  2. Conduit.site NEC tables (independent transcription of the 2020 NEC: Ch. 9 Tables 1 and 4; 250.122; 310.12; 310.15(B)(1); 310.15(C)(1); 310.16)Independent 2020-edition transcription of Table 4 (ID, area, all types incl. LFNC-C, PVC-A, PVC-EB) and Table 1
  3. Encore Wire, Raceway Fill Calculator (embedded Ch. 9 Table 4 total areas for 9 raceway types; Table 5 and 5A areas)Manufacturer copy of total areas for EMT, ENT, FMC, IMC, LFNC-B, LFMC, RMC, PVC-80, PVC-40 (0 mismatches)
  4. PDHonline Course E276 Conduit Fill Tables (2026): EMT, IMC, RMC, PVC-40, PVC-80 dimensions; THHN, THHW, XHHW 14 AWG-500 kcmil dimensionsEMT, IMC, RMC, PVC-40 and PVC-80 IDs and areas (0 mismatches); Table 1 percentages incl. 60% nipples
  5. NECA-IBEW Electricians, "Tables of NEC" (2011 NEC reprint: Ch. 9 Tables 4, 5, 5A, 8; Tables 310.15(B)(7), 310.15(B)(16), 310.15(B)(3)(a), 314.16(A), 250.66, 250.122)2011 Table 4 incl. the older ENT dimensions (edition note only)
  6. NFPA 70 A2019 cycle (2020 NEC) CMP-8 Second Draft ballot: SR-7563 Ch. 9 Table 1 notes2020 Table 1 notes (SR-7563)
  7. NFPA 70 A2022 cycle (2023 NEC) CMP-8 First Draft ballot: FR-7626 Ch. 9 Table 4 EMT trade sizes 5 and 6; FR-7593 358.20(B); FR-7580 Table 1 note 42023 EMT trade sizes 5 and 6 (FR-7626), EMT max size (FR-7593), Table 1 Note 4 (FR-7580)
  8. NFPA 70 A2022 cycle (2023 NEC) CMP-8 Second Draft ballot: SR-8183 Ch. 9 Table 4 IMC trade sizes 5 and 6; SR-8144 342.20(B)2023 IMC trade sizes 5 and 6 (SR-8183, SR-8144) - values not public in report
  9. NFPA 70 A2025 cycle (2026 NEC) CMP-8 First Draft: FR-7763 Ch. 9 Table 1 notes; FR-7525/7527/7529 314.16 (Table 314.16(B)(1) values shown)2026 Table 1 notes (FR-7763) incl. jam-ratio informational note
  10. NFPA 70 A2025 cycle (2026 NEC) CMP-8 Second Draft: no Ch. 9 Table 4/5/5A value changes; SR-8088 314.16(C)Screened for 2026 Table 4 changes (none)
  11. EC&M, "Conduit/Raceway Changes in the 2026 NEC" (Ryan Jackson, 2026)2026 PVC larger-than-6 exception; Ch. 9 tables not yet updated for those sizes
Ampacity, corrections and overcurrent devices (24)
  1. NFPA 70-2017 National Electrical Code, full text (third-party course-hosted copy; read for values only, do not link publicly)Primary transcription: Tables 310.15(B)(16)/(17), (B)(2)(a)/(b), (B)(3)(a); 240.4(D); 240.6(A); 110.14(C); rooftop adder
  2. NFPA, Proposed TIA Log 1691 to NFPA 70-2023 (reproduces the full 2023 Table 310.16; proposed 14 AWG CCA row was NOT issued)Full 2023 Table 310.16 reprint (0 mismatches); the proposed 14 AWG CCA addition was not issued
  3. NFPA, TIA 23-8 to NFPA 70-2023 (300.26: 14 AWG copper-clad aluminum control conductors, 10 A OCP, 8 A continuous)2023 14 AWG CCA control-conductor limits (10 A OCP, 8 A continuous) in 300.26
  4. NFPA issued TIAs (20-1..20-12, 23-1..23-20, 26-1..26-12) and errata (70-20-1..6, 70-23-1..10, 70-26-1..2): screened, none change these tablesConfirmed no issued TIA/errata changes these values in 2020/2023/2026
  5. Encore Wire, Wire Size and Voltage Drop Calculator (embedded Table 310.15(B)(16) Cu/Al, 30 C ambient factors, adjustment factors, 240.6(A) list, 240.4(D) limits; 2017 NEC basis)Manufacturer copy of Table 310.16 Cu/Al (all sizes), 30 C factors, adjustment factors, 240.6(A) list, 240.4(D) limits (2017 basis)
  6. Cerrowire Ampacity Chart (Rev 09/2018, (c)2021) - partial Table 310.16 (Cu 60/75/90 C, Al 75/90 C)Manufacturer chart: partial Table 310.16 (every listed cell matches)
  7. Conduit.site data file, Table 310.16 (Cu + Al), Table 310.15(B)(1), partial Table 250.122 (2020 NEC)2020 Table 310.16 Cu/Al and 30 C factors (0 mismatches)
  8. Conduit.site NEC tables (independent transcription of the 2020 NEC: Ch. 9 Tables 1 and 4; 250.122; 310.12; 310.15(B)(1); 310.15(C)(1); 310.16)2020 Table 310.15(C)(1) adjustment factors and 310.16 page
  9. NECA-IBEW Electricians, "Tables of NEC" (2011 NEC reprint: Ch. 9 Tables 4, 5, 5A, 8; Tables 310.15(B)(7), 310.15(B)(16), 310.15(B)(3)(a), 314.16(A), 250.66, 250.122)2011 Table 310.15(B)(16) and 310.15(B)(3)(a) (0 mismatches)
  10. NFPA 70 A2019 cycle (2020 NEC) CMP-10 First Draft and Second Draft ballot (no change to 240.4(D) values or Table 240.6(A))2020: no change to 240.4(D) values or Table 240.6(A)
  11. NFPA 70 A2022 cycle (2023 NEC) CMP-6 First Draft ballot: FR-8336 310.15 (Tables 310.15(B)(1)(1), (B)(1)(2), (C)(1), rooftop 19 mm); FR-8602 Ch. 9 Table 8; FR-8374 310.12 / Table 310.12(A)2023 FR-8336: renumbered ambient tables with values, adjustment table, rooftop 19 mm
  12. NFPA 70 A2022 cycle (2023 NEC) CMP-10 First Draft ballot: FR-7828 Table 240.6(A) adds 10 A; FR-7827 Class CF fuses in 240.4(D)(1)/(2)2023 FR-7828 (10 A added to Table 240.6(A)), FR-7827 (Class CF fuses)
  13. NFPA 70 A2022 cycle (2023 NEC) CMP-10 Second Draft ballot: SR-8285 240.4(D) adds (3) 14 AWG copper-clad aluminum2023 SR-8285 (240.4(D)(3) 14 AWG CCA 10 A, 8 A continuous)
  14. NFPA 70 A2022 cycle (2023 NEC) CMP-1 Second Draft ballot: SR-7793 110.14(C) and (D)2023 SR-7793: 110.14(C) text (design letters B, C, D; Table 310.16 / 310.12 basis)
  15. NFPA 70 A2025 cycle (2026 NEC) CMP-6 First Draft: FR-8036 Tables 310.16/310.17 (2023 base values; XHWN removed from 90 C), FR-7943/7953/8031 310.12, FR-7961 rooftop, FR-8033 adjustment table2026 FR-8036 (2023 base Tables 310.16/310.17; XHWN), FR-8228 (min size), FR-7961 (rooftop), FR-8033 (adjustment)
  16. NFPA 70 A2025 cycle (2026 NEC) CMP-6 Second Draft: SR-8602 Table 310.16 (18 AWG row deleted, 16 AWG Cu and 14 AWG CCA 10 A added), SR-8471/8425 minimum conductor size, SR-8473 310.12(D)2026 SR-8602 Table 310.16 changes; SR-8471/8425 minimum size and renumbering
  17. NFPA 70 A2025 cycle (2026 NEC) CMP-6 First and Second Draft ballot results (FR-8036, FR-7943, SR-8602, SR-8471 all passed)Ballot outcomes for FR-8036, FR-8228, SR-8602, SR-8471 (all passed)
  18. NFPA 70 A2025 cycle (2026 NEC) CMP-10 First Draft: FR-9210 240.6 (2023 base Table 240.6(A) incl. 10 A; fuse-only ratings 1, 3, 6, 601)2026 FR-9210: 2023 base Table 240.6(A) (with 10 A) and fuse-only list 1, 3, 6, 601
  19. NFPA 70 A2025 cycle (2026 NEC) CMP-10 Second Draft: SR-8377 240.4 wording (240.4(D) ampere limits unchanged)2026 SR-8377: 240.4(D) ampere limits unchanged
  20. NFPA 70 A2025 cycle (2026 NEC) CMP-1 First/Second Draft: 110.14 revisions (none to 110.14(C))2026: no revision of 110.14(C)
  21. IAEI Magazine, "The Reorganization of NEC Article 310" (Jul-Aug 2021)2020 renumbering of the ampacity tables; XHHN/XHWN/XHWN-2 added
  22. IAEI Magazine, "Mastering Ampacity: Understanding Conductor Sizing and Breaker Protection" (Jan 2026, 2023 NEC numbering)Independent 2023-numbering usage (310.15(B)(1)(1), (B)(1)(2), (C)(1)) and spot values
  23. IAEI Magazine, "A Look at Proposed 2026 NEC Changes" (2025)Warning that 2026 adds new sizes to Table 310.4(1)/310.16 (resolved via SR-8602/SR-8416)
  24. EC&M, "TIA Proposed for 2023 NEC Regarding Revision to Table 310.16" (Jan 2023)Context of TIA 1691 (14 AWG CCA) for the 2023 edition
Grounding and bonding conductors (9)
  1. NFPA 70-2017 National Electrical Code, full text (third-party course-hosted copy; read for values only, do not link publicly)Primary transcription of Tables 250.122, 250.66, 250.102(C)(1) and 250.66(A)-(C) (2017 edition)
  2. NECA-IBEW Electricians, "Tables of NEC" (2011 NEC reprint: Ch. 9 Tables 4, 5, 5A, 8; Tables 310.15(B)(7), 310.15(B)(16), 310.15(B)(3)(a), 314.16(A), 250.66, 250.122)Independent 2011 copy of Tables 250.122 and 250.66 (0 mismatches except the 2020 1250 kcmil change)
  3. Conduit.site NEC tables (independent transcription of the 2020 NEC: Ch. 9 Tables 1 and 4; 250.122; 310.12; 310.15(B)(1); 310.15(C)(1); 310.16)2020 Table 250.122 transcription (shows 1250 kcmil Al at 5000/6000 A)
  4. NFPA 70 A2019 cycle (2020 NEC) CMP-5 Second Draft ballot: SR-7760 Table 250.122 (Al 1200 to 1250 kcmil), SR-7825 Table 250.662020 SR-7760 (1200 -> 1250 kcmil; 250.122(B) carve-out and exception) and SR-7825 (Table 250.66 text)
  5. NFPA 70 A2022 cycle (2023 NEC) CMP-5 First Draft ballot: FR-8163 Table 250.66; FR-8258 Table 250.102(C)(1); Table 250.122 shown2023 texts of Table 250.122 (1250), Table 250.66 (FR-8163), Table 250.102(C)(1) (FR-8258), 250.66(A) CCA (FR-8098)
  6. NFPA 70 A2025 cycle (2026 NEC) CMP-5 First Draft: FR-8471 Table 250.102(C)(1) notes (2023 base values shown)2026 FR-8471 Table 250.102(C)(1) (2023 base values) and 250.66(B)/(C) caps text
  7. NFPA 70 A2025 cycle (2026 NEC) CMP-5 Second Draft: SR-8360 250.122 re-lettered, Table 250.122 values unchanged (passed ballot)2026 SR-8360 re-lettered 250.122 with Table 250.122 values (passed 19-1-1)
  8. NFPA issued TIAs (20-1..20-12, 23-1..23-20, 26-1..26-12) and errata (70-20-1..6, 70-23-1..10, 70-26-1..2): screened, none change these tablesTIA 26-12 (Table 270.122 headings, over 1000 V); no TIA/errata on Table 250.122/250.66/250.102(C)(1)
  9. IAEI Magazine, "NEC 2026 Significant Code Changes" (Jul 2025)Article 270 created from Part X of Article 250 in 2026
Boxes and box fill (10)
  1. NFPA 70-2017 National Electrical Code, full text (third-party course-hosted copy; read for values only, do not link publicly)Primary transcription of Tables 314.16(A)/(B), 314.16(A) barrier/marking numbers, 314.16(B)(1)-(5) and 300.14 free length
  2. NECA-IBEW Electricians, "Tables of NEC" (2011 NEC reprint: Ch. 9 Tables 4, 5, 5A, 8; Tables 310.15(B)(7), 310.15(B)(16), 310.15(B)(3)(a), 314.16(A), 250.66, 250.122)Independent copy of Table 314.16(A) volumes, cm3 and counts (2011)
  3. NFPA 70 A2019 cycle (2020 NEC) CMP-9 First Draft: FR-7531 314.16(B)(5) EGC fill; FR-7540 Table 314.16(A)2020 FR-7531 (EGC 1 + 1/4 rule) and FR-7540 (Table 314.16(A) and barrier text)
  4. NFPA 70 A2022 cycle (2023 NEC) CMP-9 First Draft ballot: FR-7727 Table 314.16(A) 8 AWG correction; FR-7734 314.16(B)(5); FR-7977 314.16(B)(6)2023 FR-7727 (8 AWG correction, full table text), FR-7734, FR-7977
  5. NFPA 70 A2022 cycle (2023 NEC) CMP-9 Second Draft ballot: SR-7528 314.16(B)(5); SR-7529 314.16(B)(6)2023 SR-7528 (EGC entering) and SR-7529 (terminal blocks)
  6. NFPA 70 A2025 cycle (2026 NEC) CMP-8 First Draft: FR-7763 Ch. 9 Table 1 notes; FR-7525/7527/7529 314.16 (Table 314.16(B)(1) values shown)2026 FR-7525 (Table 314.16(B)(1) values shown), FR-7527, FR-7529
  7. NFPA 70 A2025 cycle (2026 NEC) CMP-8 Second Draft: no Ch. 9 Table 4/5/5A value changes; SR-8088 314.16(C)2026 SR-8088 (conduit bodies) and screening for fill changes
  8. IAEI Magazine, "Box Fill Calculations" (Nov 2016, 2017 NEC rules)2017 counting rules incl. 12 in. loop counting twice and dryer-receptacle (two-gang device) example
  9. EC&M Code Quiz, "Box Volume Calculations and EGCs" (May 2020)2020 EGC rule (single allowance for up to four, 1/4 each additional)
  10. IAEI Magazine, "Analysis of Changes, 2020 NEC - Part I" (Mar 2019)2020 EGC change and removal of the separate 250.146(D) allowance
Dwelling service conductors (12)
  1. NFPA 70-2017 National Electrical Code, full text (third-party course-hosted copy; read for values only, do not link publicly)2017 text of 310.15(B)(7) (83% rule, 208Y/120 feeders) and Example D7
  2. NECA-IBEW Electricians, "Tables of NEC" (2011 NEC reprint: Ch. 9 Tables 4, 5, 5A, 8; Tables 310.15(B)(7), 310.15(B)(16), 310.15(B)(3)(a), 314.16(A), 250.66, 250.122)2011 Table 310.15(B)(7) values (0 mismatches)
  3. NFPA 70 A2019 cycle (2020 NEC) CMP-6 Second Draft ballot: SR-7638 new 310.12 and Table 310.12; SR-7651 310.16-310.21 conditions2020 SR-7638: 310.12 text and Table 310.12 values
  4. Conduit.site NEC tables (independent transcription of the 2020 NEC: Ch. 9 Tables 1 and 4; 250.122; 310.12; 310.15(B)(1); 310.15(C)(1); 310.16)2020 Table 310.12 transcription (0 mismatches)
  5. NFPA 70 A2022 cycle (2023 NEC) CMP-6 First Draft ballot: FR-8336 310.15 (Tables 310.15(B)(1)(1), (B)(1)(2), (C)(1), rooftop 19 mm); FR-8602 Ch. 9 Table 8; FR-8374 310.12 / Table 310.12(A)2023 FR-8374: Table 310.12(A) heading and values
  6. NFPA 70 A2022 cycle (2023 NEC) CMP-10 First Draft ballot: FR-7828 Table 240.6(A) adds 10 A; FR-7827 Class CF fuses in 240.4(D)(1)/(2)2023 FR-7803: new 240.4(H)
  7. NFPA 70 A2025 cycle (2026 NEC) CMP-6 First Draft: FR-8036 Tables 310.16/310.17 (2023 base values; XHWN removed from 90 C), FR-7943/7953/8031 310.12, FR-7961 rooftop, FR-8033 adjustment table2026 FR-7943/7953 (75 C condition, table values), FR-8031 (correction sentence moved)
  8. NFPA 70 A2025 cycle (2026 NEC) CMP-6 Second Draft: SR-8602 Table 310.16 (18 AWG row deleted, 16 AWG Cu and 14 AWG CCA 10 A added), SR-8471/8425 minimum conductor size, SR-8473 310.12(D)2026 SR-8473 (310.12(D) cleanup)
  9. NFPA 70 A2025 cycle (2026 NEC) CMP-6 First and Second Draft ballot results (FR-8036, FR-7943, SR-8602, SR-8471 all passed)Ballot outcomes for FR-7943, FR-7953, FR-8031, SR-8473 (all passed)
  10. IAEI Magazine, "The Reorganization of NEC Article 310" (Jul-Aug 2021)History: removed 2014, informative in 2017 Annex D, enforceable again in 2020
  11. IAEI Magazine, "Analysis of Changes, 2017 NEC" Parts 1 and 2 (2015)2017: old table re-inserted at Example D7; 208Y/120 proposal
  12. IAEI Magazine, "Analysis of Changes, 2020 NEC - Part I" (Mar 2019)2020: new Table 310.12 from Annex D7 / pre-2014 Table 310.15(B)(7)

NEC 2026 changes

How each 2026 change was verified: NFPA’s draft working copies and ballot results, its errata, and trade coverage after publication.

2026 revision cycle (32)
  1. CMP-2 First Draft ballot, 2023 cycle (A2022) — includes global FR-9188 Article 220 reorganization (NFPA, 2021)Documents 2020→2023 moves: 220.11→220.5(C), 220.12→220.42, 220.42→220.45, 220.43→220.46, 220.44→220.47, 220.14(J)/(K)/(M)→220.41/220.43/220.44.
  2. CMP-2 Second Draft ballot, 2023 cycle (A2022) (NFPA)Confirms 2023 220.10 list (220.41 dwelling, 220.42 non-dwelling lighting, 220.44 hotel/motel) and 220.11 Maximum Load.
  3. NEC CMP-2 First Draft working copy (A2025) (NFPA, 2024-01)
  4. NEC CMP-2 Second Draft working copy (A2025) (NFPA, 2024-10)
  5. CMP-2 First Draft final ballot results (NFPA, 2024)All FRs passed except FR-8195 (210.12(B)).
  6. CMP-2 Second Draft final ballot results (NFPA, 2025-01-09)All SRs passed except SR-7584 (210.8(F)), SR-7658, SR-7743, SR-7738 (210.12(B)).
  7. NEC Handbook 2026 errata replacement page, Table 120.54 (NFPA, 2026-03-27)
  8. NEC CMP-5 First Draft working copy (NFPA, 2024-01)
  9. NEC CMP-5 Second Draft working copy (NFPA, 2024-10)
  10. CMP-5 Second Draft final ballot (NFPA)All SRs passed.
  11. NEC CMP-6 First Draft working copy (NFPA, 2024-01)
  12. NEC CMP-6 Second Draft working copy (NFPA, 2024-10)
  13. CMP-6 Second Draft final ballot (NFPA)All SRs passed.
  14. NEC CMP-8 First Draft working copy (NFPA, 2024-01)
  15. NEC CMP-8 Second Draft working copy (NFPA, 2024-10)
  16. NEC CMP-9 First Draft working copy (NFPA, 2024-01)
  17. NEC CMP-9 Second Draft working copy (NFPA, 2024-10)
  18. NEC CMP-10 First Draft working copy (NFPA, 2024-01)
  19. NEC CMP-10 Second Draft working copy (NFPA, 2024-10)
  20. NEC CMP-11 Second Draft working copy (NFPA, 2024-10)
  21. NEC CMP-12 First Draft working copy (NFPA, 2024-01)
  22. NEC CMP-13 Second Draft working copy (NFPA, 2024-10)
  23. NEC CMP-7 Second Draft working copy (NFPA, 2024-10)
  24. NEC CMP-15 Second Draft working copy (NFPA, 2024-10)
  25. Changes to Dwelling Unit Calculations in the 2026 NEC (EC&M (Dean Austin), 2026-05-19)
  26. NEC General Requirements for Branch-Circuit, Feeder, and Service Load Calculations (EC&M (Mark Lamendola), 2026-07-07)
  27. Global Code-Wide Changes and Overview (EC&M (Ryan Jackson), 2026-07-15)
  28. A Look at the Proposed 2026 NEC Changes (IAEI Magazine (Dean Austin), 2025-07-01)
  29. Top Lighting & EV Charger Changes in the 2026 NEC (LightNOW (David Shiller), 2025-12-17)
  30. NFPA weekly update (Erratum 70-26-4, Table 430.22(H)) (Health Facilities Management, 2025-11-17)
  31. NEC 2026 load calculations (Keentel Engineering, 2026-09)Right on 2 VA/ft² and 8 kVA; wrong/2023-era on EVSE "larger of", dryer table, invents "120.12".
  32. MN electrician study guide, standard method (OpenExamPrep, 2026-10)Says EVSE = larger of 7,200 VA or nameplate and cites 120.60 — conflicts with NFPA drafts.

IEC 60364 and BS 7671 cable and protection data

Current-carrying capacities, correction factors, cable voltage drop, protective device characteristics, adiabatic k values and supply data, cross-checked against manufacturer handbooks and IET material.

Current-carrying capacity (IEC 60364-5-52) (8)
  1. Schneider Electric – Electrical Installation Guide wiki: General method for cable sizing (Fig. G20 = IEC B.52.4; read via web.archive.org snapshot 2025-11-19)B.52.4 (PVC, 3 loaded) Cu/Al all methods; installation method item numbers
  2. Schneider Electric – EIG wiki: Recommended simplified approach for cable sizing (IEC Table C.52.1; web.archive.org snapshot 2025-11-19)corroboration of A1 PVC 2LC, A1 XLPE 3LC, E/F XLPE columns where a whole simplified column equals one Annex B column
  3. ABB SACE – Electrical installation handbook, Protection, control and electrical devices, 6th edition 2010 (Tables 8, 15, 16; Table 3)A1–C, D1, D2, E, F, G for PVC/XLPE, Cu/Al; installation item mapping
  4. ABB SACE – Electrical installation handbook Vol. 2, 1st edition 2003 (1SDC010001D0201), Table 8edition-difference check (pre-2009 IEC values)
  5. EUPEN Cable – Technical data for low voltage power and control cable 0.6/1 kV, ed. 05/2022 (sections 4.2.2–4.2.5; web.archive.org snapshot 2025-01-09)B1, B2, C, D1, D2 (2 and 3 loaded, Cu 1.5–300, Al 16–300); E/F/G Cu and Al
  6. Siemens – Cable sizing with SIMARIS design for cable burying (Tab. A.1, A.2)D1 and D2, PVC and XLPE, Cu and Al
  7. Eland Cables – 6491X datasheet reproducing BS 7671 Table 4D1A (via cablejoints.co.uk; web.archive.org snapshot 2014-06-02)corroboration: BS 4D1A columns identical to IEC A1/B1 PVC and F/G PVC Cu
  8. UK Cables – Table 4E4A reproduction (hosted by TLC Direct) and IET Wiring Matters Nov 2022 (Tables 4D4A/4E4A images)corroboration: BS method D columns identical to IEC D1
Correction factors (5)
  1. Schneider Electric – EIG wiki: General method for cable sizing (Figs G12–G18; web.archive.org snapshot 2025-11-19)B.52.14, B.52.15, B.52.16, B.52.17, B.52.18 (contains a typo), B.52.21
  2. EUPEN Cable – Technical data LV power and control cable 0.6/1 kV ed. 05/2022, §4.3–4.4 (web.archive.org snapshot 2025-01-09)B.52.14–B.52.21 (all)
  3. ABB SACE – Electrical installation handbook 6th ed. 2010, Tables 5–7, 10–14B.52.16 (ducts), B.52.17, B.52.19 A/B, B.52.20, B.52.21
  4. ABB SACE – Electrical installation handbook Vol. 2, 2003 (1SDC010001D0201), Tables 10–13B.52.15, B.52.18 (2–6 circuits)
  5. Siemens – Cable sizing with SIMARIS design for cable burying (Tab. A.3–A.6)B.52.15, B.52.16 (ducts), B.52.18, B.52.19
BS 7671 Appendix 4 cable data (14)
  1. Eland Cables – 6491X datasheet (BS 7671 Tables 4D1A and 4D1B reproduced; via cablejoints.co.uk, web.archive.org 2014-06-02)4D1A all columns; 4D1B all columns
  2. Eland Cables – 624-Y Twin and Earth datasheet (BS 7671:2008 Table 4D5 extract; web.archive.org 2013-05-17)4D5 method A, method C, volt drop; CPC sizes; conductor resistance
  3. Prysmian – 6491X datasheet (via cablejoints.co.uk; web.archive.org 2009-01-05)4D1A method B; 4D1B d.c. and enclosed z; Ca; Cg
  4. Prysmian – 6181Y datasheet (via cablejoints.co.uk; web.archive.org 2009-01-05)4D1A methods B and C (1–35 mm²); 4D1B touching values; Ca; Cg
  5. Prysmian – BS 5467 multicore XLPE SWA datasheet (via cablejoints.co.uk; web.archive.org 2017-07-12)4E4B z values (2-core 1-ph, 3/4-core 3-ph)
  6. UK Cables – SWA 694_X data with BS 7671 Tables 4E4A and 4E4B (hosted by TLC Direct)4E4A, 4E4B
  7. IET Wiring Matters (Nov 2022) – Thermoplastic (PVC) or thermosetting (XLPE) SWA cable? (images of Tables 4D4A, 4E4A, 43.1)4E4A and 4D4A cross-check; 70 °C terminal limitation
  8. IET Wiring Matters (Jul 2021) – Back to the forum: thermal effects (images of Tables 4D4A and 4E4A)4D4A second reading
  9. Professional Electrician / NICEIC – The impact of thermal insulation on the current carrying capacity of flat twin and earth cables (2018)4D5 2.5 mm² methods 100–103 and C; Ci = 0.5; methods 100–103 descriptions
  10. Professional Electrician / NICEIC – Thermal insulation and its effect on flat twin & earth cables (2019)4D5 6 mm² methods 100/101; 1.0 mm² method C; Ci = 0.5
  11. IET Engineering Communities forum – XLPE Twin & Earth, Appendix 4 table, method of installation4D5 2.5 mm² method 103 (13.5 A) and method A (20 A)
  12. Doncaster Cables – 6241Y/H6242Y/H6243Y datasheet (web.archive.org)T&E CPC sizes (second source)
  13. TLC Direct – Electricians Guide (J. Whitfield) 16th-edition pages 4.3.4 and 4.3.6Ca 25 °C = 1.03; Ci 0.5 and superseded 16th-ed Ci values
  14. Professional Electrician / NICEIC – Factors affecting the current-carrying capacity of live conductors (2022)Ca/Cg/Ci table references (4B1, 4B2, 4C1–4C6, Section 2.6) and 0.5 rule
Protective devices and disconnection (11)
  1. IET Wiring Matters (May 2024) – Why are the values of maximum earth fault loop impedance different in BS 7671 to the OSG and GN3? (incl. images of GN3 Table A5 / OSG Table B6 and GN3 Table A7)Cmin = 0.95; B32 = 1.37 Ω; 0.8 rule; MCB measured values; temperature factors; Cu α
  2. IET Wiring Matters (Mar 2023) – Determining the maximum earth fault loop impedance for protective devices to BS EN 60898 & BS EN 60947-2D-curve Ia 20×In (0.4 s) and 10×In (5 s); disconnection-time table
  3. Professional Electrician / NAPIT (Feb 2023) – The requirements for automatic disconnection in case of a fault (Table 1: 80 % device Zs values; Table 2: RCDs)fuse and MCB 80 % Zs values (BS 88-2, BS 88-3, BS 3036, BS 1362, B/C/D); RCD Table 41.5; TT 1 s
  4. Professional Electrician / NICEIC (2018) – Prospective fault current: how to determine values (Table 1, BS 88-3 63 A from BS 7671 Fig 3A1)BS 88-3 63 A Ia: 600 A at 0.4 s, 320 A at 5 s
  5. Professional Electrician / NICEIC – Verification of automatic disconnection of supply (B6 = 7.28 Ω; 0.8 factor)MCB spot check
  6. Professional Electrician / NICEIC (Dec 2025) – How to determine the maximum permitted earth fault loop impedance for circuit-breakers and MCCBs (Table 1 disconnection times; Type C factor 10)disconnection times (0.4 s / 5 s); C = 10 × In
  7. Professional Electrician / NAPIT (2019) – Which maximum earth fault loop impedance values should you use?MCCB 20 × In example (0.34 Ω); Cmin usually 0.95
  8. TLC Direct – Electricians Guide (J. Whitfield, 16th ed.) 5.3.4 Earth-fault loop impedance valuesindependent fuse Ia cross-check (240 V basis)
  9. Schneider Electric – EIG wiki: Fundamental characteristics of a circuit-breaker (web.archive.org 2025)IEC 60898 B 3–5 In, C 5–10 In, D 10–20 In
  10. ABB SACE – Electrical installation handbook 6th ed. 2010 (MCB trip characteristic legend)B 3–5 In, C 5–10 In, D 10–20 In
  11. Professional Electrician / ELECSA (2018) – How to determine earth fault loop impedance80 % rule; RA × IΔn ≤ 50 V
Adiabatic equation (k values) (7)
  1. ABB SACE – Electrical installation handbook 6th ed. 2010, Annex C "Calculation of the coefficient k for the cables" (Tables 1–7)material constants B, Qc, ρ20, K; k tables (phase, separate cpc, incorporated cpc, sheath/armour, bare)
  2. ABB SACE – Electrical installation handbook Vol. 2, 2003 (1SDC010001D0201), Annex Dmaterial constants (second edition)
  3. IET Wiring Matters (Nov 2022) – Thermoplastic or thermosetting SWA cable? (image of BS 7671 Table 43.1)Table 43.1 k values and temperature limits
  4. Schneider Electric – EIG wiki: Verification of the withstand capabilities of cables under short-circuit conditions (Fig. G52) (web.archive.org 2025-11-19)phase-conductor k values and temperatures
  5. Schneider Electric – EIG wiki: Sizing of protective earthing conductor (Fig. G60) (web.archive.org 2025-11-19)cpc k values (separate and in-cable)
  6. EUPEN Cable – Technical data LV cable ed. 05/2022, §5 Thermic short circuit current ratingk Cu 143/115/103, Al 94/76/68
  7. Bayka (Bayerische Kabelwerke) – TD04EN Current carrying capacity PVC-insulated LV cables (HD 603 Table 17 short-time current densities)k at initial temperatures 20–70 °C (formula cross-check)
Supply characteristics (11)
  1. IET Wiring Matters (Sep 2018) – Earth fault loop impedance: revision of ENA Engineering Recommendation P23Ze 0.35/0.8/21 Ω; P23/2 0.34/0.64 Ω; 16 kA design PFC
  2. Professional Electrician / ELECSA (2018) – How to determine earth fault loop impedanceZe 0.8 (TN-S), 0.35 (TN-C-S), 21 Ω + electrode (TT)
  3. Professional Electrician / NICEIC – Automatic disconnection of supplyZe 0.8 / 0.35 Ω (third source)
  4. Professional Electrician / NICEIC (2018) – Prospective fault current: how to determine values16 kA conditional rating of BS EN 61439-3 consumer units
  5. IET Wiring Matters (May 2024) – Why are the values of maximum earth fault loop impedance different…Cmin = 0.95 (ESQCR); Cu α 0.00393; BS 7671 uses 0.004
  6. Schneider Electric – Cahier Technique no. 158: Calculation of short-circuit currentsIEC 60909 voltage factors cmax/cmin
  7. ABB SACE – Electrical installation handbook 6th ed. 2010, Annex C Table 1ρ20 Cu 17.241e-6 and Al 28.264e-6 Ω·mm; B (→ α20)
  8. EUPEN Cable – Technical data LV cable ed. 05/2022, §1.4 resistance conversionα20 Cu 0.00393, Al 0.00403
  9. Wikipedia – International Annealed Copper StandardIACS = 58 × 10^6 S/m at 20 °C
  10. Wikipedia – Electrical resistivity and conductivity (table of resistivities)annealed Cu 1.72e-8 Ω·m, α 3.93e-3; Al 2.82e-8 Ω·m
  11. Schneider Electric – EIG wiki: 3-phase short-circuit current (Isc) at any point within a LV installation (web.archive.org 2025-11-19)conventional short-circuit resistivities; 0.08 mΩ/m reactance
Conductor resistance (IEC 60228) (7)
  1. EUPEN Cable – Technical data LV cable ed. 05/2022, §1.1–1.2 (IEC 60228 class 1 and class 2 maximum resistances; web.archive.org 2025-01-09)Cu 1.5–300 and Al 16–300 Ω/km
  2. Prysmian – BS 5467 multicore XLPE SWA datasheet (via cablejoints.co.uk; web.archive.org 2017-07-12)Cu 1.5–300 Ω/km (second source)
  3. Prysmian – BS 6622 single-core SWA 11 kV XLPE aluminium conductor datasheet (via cablejoints.co.uk; web.archive.org 2017)Al 70–300 Ω/km (second source)
  4. Eland Cables – 624-Y Twin and Earth datasheet and 6491X datasheet (BS EN 60228 tables)Cu 1.0–16 Ω/km; T&E cpc sizes
  5. HES Kablo – BS 6004 6181Y/6192Y/6193Y datasheetCu 1.0 mm² = 18.1 Ω/km (second source)
  6. Doncaster Cables – 6241Y / H6242Y / H6243Y datasheet (web.archive.org)T&E cpc sizes
  7. IET Wiring Matters (May 2024) – Why are the values of maximum earth fault loop impedance different…R1+R2 1.5/1.0 = 0.0302 Ω/m; 1.2 multiplier; α 0.004

Electronics component data

Marking codes, preferred values and typical part characteristics from IEC standards and manufacturer datasheets.

Resistor colour code (11)
  1. IEC 60062:2016 Ed. 6.0 "Marking codes for resistors and capacitors" — publisher preview (foreword, clauses 1–4.2, Table 1, Figures 1–6)Table 1 colour prescriptions (digit, multiplier, tolerance, TCR, IEC 60757 colour letters); band-layout rules; TCR-band methods; list of changes vs 2004; RKM letters L/R/K/M/G
  2. IEC 60062:2004 Ed. 5.0 "Marking codes for resistors and capacitors" — publisher preview (foreword, clauses 1–4.2, Table 1)Previous-edition colour table (no pink, no yellow/grey tolerance), 6th-band rules, RKMG letters incl. T; edition history (replaced 4th ed. 1992 + A1:1995)
  3. IEC webstore — IEC 60062:2016+AMD1:2019 CSV (consolidated version, Ed. 6.1)Existence/date of Amendment 1 (2019-08-20), edition number 6.1, stability date 2033
  4. Panasonic Industry — "Resistor Color Codes: Thorough Explanations of How to Interpret, Calculate, and Remember Them!" (technical article b27)Manufacturer cross-check of digits, multipliers, TCR values; shows the legacy grey = ±0.05 % tolerance
  5. YAGEO RT series thin-film chip resistor product specification (V.16, 2025-05-06)Tolerance letters L ±0.01 %, P ±0.02 %, W ±0.05 %, B ±0.1 %, C ±0.25 %, D ±0.5 %, F ±1 %
  6. KEMET (YAGEO Group) C0G SMD MLCC datasheet C1003_C0G (2025-02-20)Tolerance letters F ±1 %, G ±2 %, J ±5 %, K ±10 %, M ±20 % (shared letter system)
  7. Panasonic ERA-xA thin-film chip resistor line-extension brief (EC-ERA-xA Line Ext 2012)Tolerance letters W ±0.05 %, B ±0.1 %, D ±0.5 %
  8. MIL-R-39008C (1990-08) Resistors, fixed, composition (insulated), established reliability — via EverySpecFailure-rate levels M/P/R/S (1/0.1/0.01/0.001 % per 1000 h at 50 % rated power) and their 5th-band colours
  9. MIL-STD-1285D (2004-09) Marking of electrical and electronic parts — Table II and Appendix A — via EverySpecCross-check of failure-rate band colours (5th code element); worked example 4300 Ω ±5 % level M
  10. Wikipedia — Electronic color code (secondary cross-check only)Secondary cross-check; history of grey ±0.05 % (EIA RS-279); TCR letters (conflicts with RKM article)
  11. Wikipedia — RKM code (secondary cross-check only)Secondary cross-check of IEC 60062 tolerance letters and TCR letters
E-series preferred values (7)
  1. Vishay Sfernice — "Standard Ohmic Values" (Document 50034, rev. 14-Aug-13)E3, E6, E12, E24, E48, E96, E192 lists; tolerance printed under each series column
  2. Vishay Dale — "Standard Electronic Decade Value Tables" (Document 31001, rev. 04-Oct-06)Independent copy of E12, E24, E96, E192; tolerance-to-series statement (E24 for ±2 %/±5 %, E192 for ±0.1/0.25/0.5 %)
  3. IEC webstore — IEC 60063:2015 "Preferred number series for resistors and capacitors"Edition 3.0, published 2015-03-27, stability date 2033; summary of changes vs previous edition
  4. IEC 60062:2004 Ed. 5.0 — publisher preview (normative references, scope)Shows the earlier IEC 60063:1963 edition being referenced; colour code intended for E6…E192
  5. Vishay D/CRCW e3 standard thick-film chip resistors (Document 20035, rev. 14-Apr-2026)Evidence that ±1 % parts are sold in E24 and E96 values and ±5 % parts in E24 (series ≠ tolerance in practice)
  6. KEMET (YAGEO Group) X7R SMD MLCC datasheet C1002_X7R (2026-09-01)Capacitors offered in "E24 decade values" or "E12 decade values" depending on range
  7. Wikipedia — E series of preferred numbers (secondary, not relied on for values)Secondary context only
SMD resistor codes (8)
  1. Bourns CR Series thick-film chip resistors datasheet (REV. 03/21)EIA-96 code table 01–96, multiplier letters A–H/X/Y/Z, marking by size (E24 3-digit, E96 4-digit, 0603 E96 EIA-96), 0 Ω jumper marked "0", no marking ≤0402, examples 103 / 4422 / 10C
  2. YAGEO RT series thin-film chip resistor product specification (V.16, 2025-05-06)RT0603 marking: E24 values (except 10/11/13/15/20/75) as 3 digits with a short bar under the marking, E96 as EIA-96 3 characters; ≥0805: 4 digits for E24 and E96; ≤0402: no marking; examples 563 / 10C / 1002
  3. IEC 60062:2016 Ed. 6.0 — publisher preview (clause 4.2 RKM code, contents list incl. Annex A tables)RKM letters L/R/K/M/G (L = milli), Tables 2–4 examples, 3-character code limited to E24 and coarser, existence of Annex A (E96 three-character code)
  4. IEC 60062:2004 Ed. 5.0 — publisher preview (clause 4.2.1 RKMG code)Previous letter set R, K, M, G, T (T = 10^12)
  5. Vishay D/CRCW e3 standard thick-film chip resistors (Document 20035, rev. 14-Apr-2026)Jumper (0 Ω) max resistance ≤20 mΩ and max current per size; imperial ↔ metric size codes
  6. KOA Speer RK73H precision thick-film chip resistor datasheet (2026-01-27)Cross-check of EIA imperial size names (01005…2512)
  7. DigiKey TechForum — "SMD Resistor Code; Surface Mount Resistor Part Markings" (2022-07-18)Worked example 09B = 1.21 kΩ; note that bar symbols are maker/series specific and small sizes are unmarked
  8. Vishay Dale — "Standard Electronic Decade Value Tables" (Document 31001)E96 list used to check the EIA-96 table
Capacitor codes (14)
  1. KEMET (YAGEO Group) SMD MLCC, C0G dielectric — datasheet C1003_C0G (2025-02-20)pF code with 9 (1.0–9.9 pF) and 8 (0.5–0.99 pF); tolerance letters B, C, D, F, G, J, K, M; C0G = 0 ±30 ppm/°C, −55…+125 °C; KEMET numeric voltage codes
  2. KEMET (YAGEO Group) SMD MLCC, X7R dielectric — datasheet C1002_X7R (2026-09-01)X7R = ±15 %, −55…+125 °C (EIA class II); KEMET voltage code 6 = 35 V; E24/E12 decade values
  3. KEMET (YAGEO Group) SMD MLCC, X5R dielectric — datasheet C1006_X5R (2026-09-07)X5R = ±15 %, −55…+85 °C (EIA class II)
  4. KEMET SMD MLCC, Y5V dielectric — datasheet C1005_Y5V_SMD (2025-02-20)Y5V = +22/−82 %, −30…+85 °C (KEMET calls it EIA class III); tolerance Z = +80/−20 %; KEMET voltage code 9 = 6.3 V
  5. KEMET (YAGEO Group) T491 MnO2 tantalum chip capacitors — datasheet T2005_T491 (2026-07-08)Tantalum polarity: stripe (and sometimes a bevel) marks the positive terminal; transient reverse-voltage limits 15 % @25 °C, 5 % @85 °C
  6. KYOCERA AVX TAJ standard tantalum capacitors datasheetpF code (two significant figures + number of zeros): 106 = 10 µF, 227 = 220 µF; voltage letters A = 10 V, J = 6.3 V; polarity band = anode (+); K = ±10 %, M = ±20 %
  7. Vishay 293D solid tantalum chip capacitors (Document 40002, rev. 02-Jul-2025)A-case voltage letters G 4, J 6.3, A 10, C 16, D 20, E 25, V 35, T 50, S 75; anode (+) polarity band; 6.3 V parts marked "6 V"
  8. Nichicon UVR aluminium electrolytic capacitors (CAT.8100M)Two-character voltage codes 0J…2W; µF-based capacitance code in part numbers (UVR1A332MHD = 10 V 3300 µF); radial drawing with the positive lead ≥4 mm longer
  9. Nichicon catalogue pages CAT.8100M: UVZ, UVY, UVK, UPW, UCY, LGU, LGY, LLS, LGX, PCG, PCL, PCM, PCR, PCX, PLV, RNE, RNL, RNS, RNUVoltage codes 0E 2.5, 0G 4, 1D 20, 1K 80, 2Z 180, 2P 220, 2F 315, 2H 500 (URL pattern e-<series>.pdf)
  10. Nichicon UCV chip-type aluminium electrolytic capacitors (CAT.8100M)Can-top voltage letters C 16 V, E 25 V, V 35 V; negative side marked on the case top
  11. Nichicon LGN snap-in aluminium electrolytic capacitors (CAT.8100M)Polarity bar on the sleeve sits over the negative terminal; codes 2X = 600 V, 2H = 500 V
  12. IEC 60062:2016 Ed. 6.0 — publisher preview (contents list)Confirms the standard has a pF-based and a µF-based three-character capacitance code (Tables 10, 11) and tolerance tables (12–14); contents of those tables not visible
  13. Wikipedia — Ceramic capacitor (secondary cross-check)EIA RS-198 class 1 and class 2 code tables
  14. Wikipedia — RKM code (secondary cross-check)Asymmetric tolerance letters Q/S/T; absolute pF tolerances; RKM capacitance letters p/n/µ/m
LED forward voltages (6)
  1. Kingbright datasheets (part number in each row; URL pattern https://www.kingbrightusa.com/images/catalog/SPEC/<part>.pdf, "/" in a part number becomes "-")VF typ/max and test current, abs-max DC current, VF temperature coefficient, reverse-voltage limit for 3 mm, 5 mm, 0603, 0805 and tri-colour PLCC parts
  2. Würth Elektronik WL-SMCW 0603 mono-colour chip LED datasheets (150060xS75000; rev 002.009 / 001.001, 2019-02-26)Second-manufacturer VF for red, super red, amber, yellow, bright green (AlInGaP), green and blue (InGaN), white
  3. Würth Elektronik WL-TMRC 5 mm THT round LED datasheet 151051RS11000 (rev 003.001, 2021-08-31)Second-manufacturer VF for a 5 mm red (AlGaInP) LED
  4. Vishay TSAL6200 940 nm IR emitting diode, 5 mm (Document 81010, rev. 2.4, 13-Mar-14)Second-manufacturer IR VF (1.35 typ / 1.6 max at 100 mA; 2.2 typ at 1 A pulsed), IF max 100 mA
  5. Bivar SM0603UV-405 / SM0603UV-400 UV 0603 LED datasheets (Revision A, 06/14)UV (400–410 nm) VF 3.4 typ / 4.2 max at 20 mA, IF max 25 mA
  6. Wikipedia — Light-emitting diode, colour/voltage table (secondary sanity check only)Order-of-magnitude check of VF ranges per colour (IR < 1.9 V … UV 3.1–4.4 V)
555 timer (6)
  1. Texas Instruments NA555/NE555/SA555/SE555 Precision Timers (SLFS022K, Sept 1973 – rev. March 2026)Supply 4.5–16 V (SE555 18 V), ±200 mA output, threshold/trigger levels, max RA+RB vs VCC, ≤100 kHz advice, 10 µs minimum pulse, astable/monostable equations, CONT 0.01 µF, 0.1 µF bypass
  2. Texas Instruments LM555 Timer (SNAS548D, Feb 2000 – rev. Jan 2015)Supply 4.5–16 V, 200 mA output, 1 %/2.25 % initial timing accuracy, max RA+RB 20 MΩ, 5 s worked example (100 kΩ, 47 µF), reset timing, layout parts list
  3. Texas Instruments TLC555 CMOS Timer (SLFS043K, Aug 1983 – rev. Jan 2026)Supply 2–15 V, 180 µA at 5 V, sink 100 mA / source 10 mA typ, fmax 2.1 MHz typ, 1 µs minimum pulse, validity of equations below 100 kHz, ln2…ln3 limits, bypass and CONT advice
  4. Texas Instruments LMC555 CMOS Timer (SNAS558N, Jan 2000 – rev. March 2024)Supply 1.5–15 V, fmax 3 MHz, 180 µA at 5 V, output abs-max 100 mA, 20 ns trigger / 400 ns reset minimum, equations
  5. Renesas ICM7555/ICM7556 General Purpose CMOS Timers (FN2867 rev. 10.01, 2020-03-05)Monostable written as −ln(1/3)·RA·C = 1.1·RA·C; 2–18 V, 1 MHz; 50 %-duty output-fed RC variant f = 1/(1.4·R·C); CMOS vs bipolar supply-current spikes
  6. Diodes Incorporated NE555/SA555/NA555 Precision Timer (DS35112 rev. 5-2, Feb 2021)Second-maker confirmation of bipolar equations and max RA+RB (3.4 MΩ at 5 V, 10 MΩ at 15 V)
Standard component values (19)
  1. Vishay Sfernice — Standard Ohmic Values (doc 50034)E-series lists (see e-series.ts)
  2. Nichicon UVR aluminium electrolytic capacitors (CAT.8100M)Capacitance values actually offered (1 µF … 22 000 µF), ±20 % tolerance
  3. KEMET C0G SMD MLCC datasheet C1003_C0G (2025-02-20)C0G ranges include E24 decade values; tolerances B…M
  4. KEMET X7R SMD MLCC datasheet C1002_X7R (2026-09-01)X7R ranges include "E24 decade values only" or "E12 decade values only"; tolerances ±5/±10/±20 %
  5. KEMET X5R SMD MLCC datasheet C1006_X5R (2026-09-07)X5R tolerances K (±10 %), M (±20 %)
  6. KEMET Y5V SMD MLCC datasheet C1005_Y5V_SMD (2025-02-20)Y5V tolerances M (±20 %), Z (+80/−20 %); 0.022–22 µF
  7. Bourns CR thick-film chip resistors (REV. 03/21)Power @70 °C and max working voltage, 01005…2512
  8. Vishay D/CRCW e3 thick-film chip resistors (doc 20035, rev. 14-Apr-2026)P70 and Umax, 0402…2512 incl. 1210/1218; E24 for ±5 %, E24+E96 for ±1 %
  9. KOA Speer RK73H precision thick-film chip resistors (2026-01-27)Power rating and max working voltage per size, 01005…2512 (incl. 2 W 2512 variant)
  10. YAGEO RT thin-film chip resistors (V.16, 2025-05-06)Thin-film power ratings per size (lower than thick film for 1210/2512)
  11. Panasonic ERA-xA thin-film chip resistor brief (2012)Power 0.063 W (0402), 0.1 W (0603), 0.125 W (0805), 0.25 W (1206)
  12. KOA Speer CF carbon-film leaded resistors (2020-09-01)Through-hole 0.25 W and 0.5 W ratings and body sizes
  13. KOA Speer MOS metal-oxide leaded resistorsThrough-hole 1/2, 1, 2, 3, 5 W type names
  14. Vishay MBA/SMA 0204, MBB/SMA 0207, MBE/SMA 0414 professional thin-film leaded resistors (doc 28766, rev. 11-Jul-2018)P70 by DIN body size: 0204 0.4 W, 0207 0.6 W, 0414 1.0 W
  15. Bourns SDR0604 SMD power inductors (REV. 04/26)"Available in E12 series"; ±20 % tolerance
  16. Bourns SRR1260 shielded SMD power inductors (REV. 03/26)"Available in E12 values"; 1.0–1000 µH; ±30 % (low values) / ±20 %
  17. Bourns SRN6045 semi-shielded SMD power inductors (REV. 01/20)Value set close to E6 (10, 15, 22, 33, 47, 68 µH …)
  18. TI NE555 datasheet (SLFS022K)Example of standard decoupling values (0.1 µF, 0.01 µF)
  19. TI LM555 datasheet (SNAS548D)Bypass recommendation 0.1 µF ceramic in parallel with 1 µF electrolytic; 0.01 µF on CONT

Simulator

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Last updated 2026-10-14.