JohdotaDevice guide Play

Johdota device guide

Regions

The guide and the game follow IEC practice. Choose your region to see what is different in your country.

The table compares your region with IEC practice. Each fact has a source. If something is wrong or out of date for your country, please send feedback.

UK & IrelandEuropeAustralia & New ZealandOther IEC countriesUnited StatesCanada
Supply230/400 V, 50 Hz. Great Britain: 230 V +10% / −6%. Ireland: 207–253 V.[1][2][3]230/400 V, 50 Hz. Supply quality to EN 50160.[1][4][5]230/400 V, 50 Hz. Australia: 230 V +10% / −6%. New Zealand: 230 V ±6%. In Australia the nominal used to be 240 V, and older equipment may be marked 240 V.[6][7][8][9][10]230/400 V in IEC 60038, but 220/380 V and 240/415 V systems still exist. Some countries use 60 Hz.[1][4]120/208 V, 277/480 V and 120/240 V, 60 Hz.[11]120/208 V and 347/600 V, 60 Hz.[12][1]
Building wiring rulesBS 7671 (UK), I.S. 10101 (Ireland).[13][14]National rules. The international series is IEC 60364.[5]AS/NZS 3000.[15]National rules. The international series is IEC 60364.[5]NEC (NFPA 70).[16]Canadian Electrical Code (CEC), Part I, published by CSA.[17]
Machine wiringBS EN 60204-1. Guidance from 2004 notes that BS 7671 does not cover wiring inside control panels.[18][19]EN 60204-1.[20][21]AS/NZS 4024.1204 (IEC 60204-1 with national modifications).[22]IEC 60204-1.[5]NFPA 79.[23]CSA C22.2 No. 301.[24]
Phase coloursBrown, black, grey. The UK used red, yellow and blue before 2006.[25][19][26]Called actives. Any colour except green, yellow, green/yellow, black or light blue. Recommended for multiphase: red, white, blue. These colours are for installation wiring, not for wiring inside equipment or switchboards.[27][28]Depends on the country.Not set by the NEC. Common: black, red, blue (208 V); brown, orange, yellow (480 V).[29]Where colour-coded: red, black, blue for phases A, B, C (CEC Rule 4-032).[30][31]
NeutralBlue. The UK used black before 2006.[25][19]Black or light blue. In New Zealand homes, black only.[27]Depends on the country.White or grey.[32]White (CEC Rule 4-024).[30]
Protective earthGreen-and-yellow, used only for protective conductors.[25][28][33]Green, or green with yellow stripes, for equipment grounding (USA) and bonding (Canada) conductors.[34][30]
Control wiring in machinesRecommended: black for power, red for AC control, blue for DC control, orange for circuits that stay live when the main switch is off.[33]AS/NZS 4024.1204 is based on IEC 60204-1. We have not checked whether it changes this.[22]Recommended: black for power, red for AC control, blue for DC control, orange for circuits that stay live when the main switch is off.[33]Where colour coding is used: black for power, red for AC control, blue for DC control, other colours permitted. Required: orange (AC) or orange with a blue stripe (DC) for circuits that stay live with the disconnect off.[16][23]We have not checked this yet.
Start and stop buttonsStart: white preferred, also grey, black or green. Stop: black preferred, also grey or white; red allowed.[35]AS/NZS 4024.1204 is based on IEC 60204-1. We have not checked whether it changes this.[22]Start: white preferred, also grey, black or green. Stop: black preferred, also grey or white; red allowed.[35]Start: green preferred. Stop: red preferred. Black, white or grey allowed for both.[36]We have not checked this yet.
Device lettersJohdota uses the common single letters K, Q, S, H, F, M and B. IEC 81346-2:2019 has two-letter codes, for example BG for a limit switch and BC for an overload relay.[37]NFPA 79 Annex E: PB pushbutton, CR control relay, M motor starter, TR timer relay, LS limit switch, OL overload relay, LT pilot light, DISC disconnecting means. A number tells several apart: 1PB, 2PB.[38][39]
Diagram symbolsIEC 60617, now an online database.[40]Ladder diagrams with IEEE 315 and NEMA-style symbols, as in NFPA 79 Annex D. See the symbols.[23][41]
Motor terminalsU1, V1, W1 and U2, V2, W2.[42]T1 to T12 (NEMA). Dual-voltage motors may have nine leads.[43][44]
FusesBS 88. Motor fuses can be gM, such as 32M50.[45][46]IEC 60269: gG general purpose, aM and gM for motor circuits.[46]The AS adoption of IEC 60269-1 has been withdrawn.[47]IEC 60269: gG general purpose, aM and gM for motor circuits.[46]UL classes such as J, RK1, RK5 and CC. Class J is HRCI-J in Canada.[48]
Local isolatorIsolator.[13]Switch-disconnector.[5]Isolating switch.[49]Switch-disconnector.[5]Disconnect, or safety switch.[50][39]

UK & Ireland

Supply
230/400 V, 50 Hz. Great Britain: 230 V +10% / −6%. Ireland: 207–253 V.[1][2][3]
Building wiring rules
BS 7671 (UK), I.S. 10101 (Ireland).[13][14]
Machine wiring
BS EN 60204-1. Guidance from 2004 notes that BS 7671 does not cover wiring inside control panels.[18][19]
Phase colours
Brown, black, grey. The UK used red, yellow and blue before 2006.[25][19][26]
Neutral
Blue. The UK used black before 2006.[25][19]
Protective earth
Green-and-yellow, used only for protective conductors.[25][28][33]
Control wiring in machines
Recommended: black for power, red for AC control, blue for DC control, orange for circuits that stay live when the main switch is off.[33]
Start and stop buttons
Start: white preferred, also grey, black or green. Stop: black preferred, also grey or white; red allowed.[35]
Device letters
Johdota uses the common single letters K, Q, S, H, F, M and B. IEC 81346-2:2019 has two-letter codes, for example BG for a limit switch and BC for an overload relay.[37]
Diagram symbols
IEC 60617, now an online database.[40]
Motor terminals
U1, V1, W1 and U2, V2, W2.[42]
Fuses
BS 88. Motor fuses can be gM, such as 32M50.[45][46]
Local isolator
Isolator.[13]

Europe

Supply
230/400 V, 50 Hz. Supply quality to EN 50160.[1][4][5]
Building wiring rules
National rules. The international series is IEC 60364.[5]
Machine wiring
EN 60204-1.[20][21]
Phase colours
Brown, black, grey. The UK used red, yellow and blue before 2006.[25][19][26]
Neutral
Blue. The UK used black before 2006.[25][19]
Protective earth
Green-and-yellow, used only for protective conductors.[25][28][33]
Control wiring in machines
Recommended: black for power, red for AC control, blue for DC control, orange for circuits that stay live when the main switch is off.[33]
Start and stop buttons
Start: white preferred, also grey, black or green. Stop: black preferred, also grey or white; red allowed.[35]
Device letters
Johdota uses the common single letters K, Q, S, H, F, M and B. IEC 81346-2:2019 has two-letter codes, for example BG for a limit switch and BC for an overload relay.[37]
Diagram symbols
IEC 60617, now an online database.[40]
Motor terminals
U1, V1, W1 and U2, V2, W2.[42]
Fuses
IEC 60269: gG general purpose, aM and gM for motor circuits.[46]
Local isolator
Switch-disconnector.[5]

Australia & New Zealand

Supply
230/400 V, 50 Hz. Australia: 230 V +10% / −6%. New Zealand: 230 V ±6%. In Australia the nominal used to be 240 V, and older equipment may be marked 240 V.[6][7][8][9][10]
Building wiring rules
AS/NZS 3000.[15]
Machine wiring
AS/NZS 4024.1204 (IEC 60204-1 with national modifications).[22]
Phase colours
Called actives. Any colour except green, yellow, green/yellow, black or light blue. Recommended for multiphase: red, white, blue. These colours are for installation wiring, not for wiring inside equipment or switchboards.[27][28]
Neutral
Black or light blue. In New Zealand homes, black only.[27]
Protective earth
Green-and-yellow, used only for protective conductors.[25][28][33]
Control wiring in machines
AS/NZS 4024.1204 is based on IEC 60204-1. We have not checked whether it changes this.[22]
Start and stop buttons
AS/NZS 4024.1204 is based on IEC 60204-1. We have not checked whether it changes this.[22]
Device letters
Johdota uses the common single letters K, Q, S, H, F, M and B. IEC 81346-2:2019 has two-letter codes, for example BG for a limit switch and BC for an overload relay.[37]
Diagram symbols
IEC 60617, now an online database.[40]
Motor terminals
U1, V1, W1 and U2, V2, W2.[42]
Fuses
The AS adoption of IEC 60269-1 has been withdrawn.[47]
Local isolator
Isolating switch.[49]

Other IEC countries

Supply
230/400 V in IEC 60038, but 220/380 V and 240/415 V systems still exist. Some countries use 60 Hz.[1][4]
Building wiring rules
National rules. The international series is IEC 60364.[5]
Machine wiring
IEC 60204-1.[5]
Phase colours
Depends on the country.
Neutral
Depends on the country.
Protective earth
Green-and-yellow, used only for protective conductors.[25][28][33]
Control wiring in machines
Recommended: black for power, red for AC control, blue for DC control, orange for circuits that stay live when the main switch is off.[33]
Start and stop buttons
Start: white preferred, also grey, black or green. Stop: black preferred, also grey or white; red allowed.[35]
Device letters
Johdota uses the common single letters K, Q, S, H, F, M and B. IEC 81346-2:2019 has two-letter codes, for example BG for a limit switch and BC for an overload relay.[37]
Diagram symbols
IEC 60617, now an online database.[40]
Motor terminals
U1, V1, W1 and U2, V2, W2.[42]
Fuses
IEC 60269: gG general purpose, aM and gM for motor circuits.[46]
Local isolator
Switch-disconnector.[5]

United States

Supply
120/208 V, 277/480 V and 120/240 V, 60 Hz.[11]
Building wiring rules
NEC (NFPA 70).[16]
Machine wiring
NFPA 79.[23]
Phase colours
Not set by the NEC. Common: black, red, blue (208 V); brown, orange, yellow (480 V).[29]
Neutral
White or grey.[32]
Protective earth
Green, or green with yellow stripes, for equipment grounding (USA) and bonding (Canada) conductors.[34][30]
Control wiring in machines
Where colour coding is used: black for power, red for AC control, blue for DC control, other colours permitted. Required: orange (AC) or orange with a blue stripe (DC) for circuits that stay live with the disconnect off.[16][23]
Start and stop buttons
Start: green preferred. Stop: red preferred. Black, white or grey allowed for both.[36]
Device letters
NFPA 79 Annex E: PB pushbutton, CR control relay, M motor starter, TR timer relay, LS limit switch, OL overload relay, LT pilot light, DISC disconnecting means. A number tells several apart: 1PB, 2PB.[38][39]
Diagram symbols
Ladder diagrams with IEEE 315 and NEMA-style symbols, as in NFPA 79 Annex D. See the symbols.[23][41]
Motor terminals
T1 to T12 (NEMA). Dual-voltage motors may have nine leads.[43][44]
Fuses
UL classes such as J, RK1, RK5 and CC. Class J is HRCI-J in Canada.[48]
Local isolator
Disconnect, or safety switch.[50][39]

Canada

Supply
120/208 V and 347/600 V, 60 Hz.[12][1]
Building wiring rules
Canadian Electrical Code (CEC), Part I, published by CSA.[17]
Machine wiring
CSA C22.2 No. 301.[24]
Phase colours
Where colour-coded: red, black, blue for phases A, B, C (CEC Rule 4-032).[30][31]
Neutral
White (CEC Rule 4-024).[30]
Protective earth
Green, or green with yellow stripes, for equipment grounding (USA) and bonding (Canada) conductors.[34][30]
Control wiring in machines
We have not checked this yet.
Start and stop buttons
We have not checked this yet.
Device letters
NFPA 79 Annex E: PB pushbutton, CR control relay, M motor starter, TR timer relay, LS limit switch, OL overload relay, LT pilot light, DISC disconnecting means. A number tells several apart: 1PB, 2PB.[38][39]
Diagram symbols
Ladder diagrams with IEEE 315 and NEMA-style symbols, as in NFPA 79 Annex D. See the symbols.[23][41]
Motor terminals
T1 to T12 (NEMA). Dual-voltage motors may have nine leads.[43][44]
Fuses
UL classes such as J, RK1, RK5 and CC. Class J is HRCI-J in Canada.[48]
Local isolator
Disconnect, or safety switch.[50][39]

Ladder diagrams in the USA and Canada

North American control circuits are drawn as ladder diagrams. The control supply runs down two vertical rails, and each circuit is a horizontal rung between them. The wires are numbered, so a three-wire control rung reads 1 – STOP – 2 – START – 3.[51][41]

The control supply often comes from a control transformer. Its secondary terminals are X1 and X2.[52][41]

These are the symbols the English game uses for the US and Canada, with the letters from NFPA 79 Annex E. Contacts are shown in their normal state, with no power on the circuit.[41][53][54][38]

The symbols come from US standards and makers. IEEE 315, the US symbol standard, was also published in Canada as CSA Z99 in 1975, but it is no longer maintained. We have not found a newer Canadian rule for diagram symbols, so the English game uses the same symbols in Canada. If you know how this is done in Canada, please send feedback.[55][56]

2PB
Pushbutton, NO · PB
1PB
Pushbutton, NC · PB
ESTOP
Emergency stop · ESTOP
HXOFFASS
Selector switch contact · SS
R2LT
Pilot light, red · LT
ABU
Buzzer · ABU
CR
Control relay coil · CR
M
Motor starter coil · M
1TR5 s
Timer relay coil · TR
CR
Contact, NO
CR
Contact, NC
1TRNOTC
Timed contact NOTC
1TRNCTO
Timed contact NCTO
2TRNOTO
Timed contact NOTO
2TRNCTC
Timed contact NCTC
LS
Limit switch, NO · LS
LS
Limit switch, NC · LS
PRS
Proximity switch · PRS
PS
Pressure switch · PS
FS
Float switch · FS
TAS
Temperature switch, NC · TAS
SOLvalve
Solenoid valve · SOL
ML1 L2 L3T1 T2 T3
Starter main contacts · M
OL
Overload heaters · OL
DISCL1 L2 L3T1 T2 T3
Disconnect · DISC
CBL1 L2 L3T1 T2 T3
Circuit breaker with thermal trip · CB

Sources

  1. IEC 60038:2009 Standard voltages (public copy)
  2. UK ESQCR 2002, regulation 27: supply voltage and frequency
  3. ESB Networks: standard voltage in Ireland
  4. IEC: World Plugs, voltage and frequency by country
  5. IEC 60204-1:2016+AMD1:2021 preview (contents and foreword)
  6. Standards Australia: AS/NZS 3000:2018, Clause 1.6.2 supply voltage and tolerances
  7. Standards Australia: AS IEC 60038:2022 Standard voltages
  8. Essential Services Commission, Victoria: Electricity Distribution Code of Practice (2026)
  9. New Zealand Electricity (Safety) Regulations 2010 (third-party copy)
  10. Electrical Connection: When voltage varies (2012)
  11. PacifiCorp: power quality standards, ANSI C84.1 system voltages
  12. BC Hydro: electrical service voltages
  13. IET Wiring Matters: isolation and switching for mechanical maintenance (2023)
  14. NSAI: national rules for electrical installations I.S. 10101 (2024)
  15. Standards Australia: AS/NZS 3000:2018 Wiring rules
  16. NFPA 79 public input report, 2024 edition (13.2.3, 13.2.4)
  17. Electrical Industry News Week: motor rules in CEC Section 28 (2021)
  18. UK government: designated standards for machinery (list v16, 2026)
  19. GAMBICA: harmonised cable colours, guidance for machinery (2004)
  20. European Commission: harmonised standards for machinery (summary list)
  21. DIN Media: EN 60204-1:2018+A1:2025
  22. Standards Australia: AS/NZS 4024.1204:2019 (IEC 60204-1:2016 MOD)
  23. NFPA 79 Second Draft report, 2024 edition (13.2.4, Annex D)
  24. Standards Council of Canada: CSA C22.2 No. 301:23 Industrial electrical machinery
  25. Lapp: cable colour codes, HD 308 S2 core identification
  26. IET Wiring Matters: new cable colours agreed (2004)
  27. Standards Australia: AS/NZS 3000:2018, Clause 3.8.1 and Table 3.4 conductor colours
  28. Prysmian Australia: green/yellow is never an active or neutral (2016)
  29. Mike Holt, EC&M: identification of branch-circuit conductors (2017)
  30. Electrical Safety Authority (Ontario): Bulletin 4-5-15, conductor colours (2025)
  31. Alberta Municipal Affairs: STANDATA 24-ECB-004, 2024 CEC Section 4 (2025)
  32. EC&M: identification of grounded conductors, NEC 200.6 (2012)
  33. IDEC: IEC 60204-1 summary (wire, push-button and indicator colours)
  34. Mike Holt: NEC 250.119, equipment grounding conductor
  35. Schneider Electric FAQ FA28043: push-button colours in IEC 60204-1
  36. NFPA 79 First Draft report, 2026 cycle (shows the 2024 text of 10.2.2)
  37. IEC 81346-2:2019 sample (letter codes)
  38. NFPA 79 First Draft report, 2024 edition (13.2.3, Annex E Table E.1 device designations)
  39. Siemens: Basics of Control Components, part 1 (STEP 2000 course)
  40. IEC webstore: IEC 60617 graphical symbols database
  41. Square D (Schneider Electric): Wiring Diagram Book 0140CT9201, symbols and examples
  42. ABB: low voltage motors manual (terminals and rotation)
  43. WEG: motor installation manual, NEMA and IEC lead markings
  44. AEMC Instruments: testing three-phase dual-voltage motors (connection tables)
  45. Eaton Bussmann: BS 88 fuse 32M50 (gM)
  46. Schneider Electric: Electrical Installation Guide, fuse classes gG, gM and aM
  47. Standards Australia: AS 60269.1-2005 (withdrawn)
  48. Littelfuse: POWR-GARD fuse catalogue, application guide
  49. Kraus & Naimer Australia and New Zealand: isolators explained
  50. Siemens: heavy duty safety switches, catalogue extract
  51. EC&M: Electrical ladder drawing basics (2006)
  52. Hammond Power Solutions: control transformer wiring diagrams CAWD2
  53. Evolution Motion: JIC standard graphic symbols for electrical ladder diagrams
  54. Eaton: Comparison of NEMA and IEC schematic diagrams, MZ081001EN (university copy)
  55. IEEE SA: IEEE 315-1975 graphic symbols for electrical diagrams (inactive)
  56. Intertek Inform: IEEE 315-1975 listing, contents include the Canadian Standard Z99 modifications