I. International Standards
What to look for in international standards? Based on International Electrotechnical Commission (IEC) practices, the standards should be viewed as follows: Core Standard—IEC 60204-1 (Safety of machinery – Electrical equipment of machines – Part 1: General requirements; published by the IEC; the core standard for electrical safety in machinery);
Version—IEC 60204-1:2016 (consolidated version including the 2016 edition and Amendment 1:2021; the latest version released in 2021 supersedes the 2016 edition and serves as the current international standard); Scope—Applies to the electrical, electronic, and programmable electronic equipment and systems of machinery (including groups of machines working in a coordinated manner); covers non-handheld machinery and all aspects of electrical control systems—such as industrial automation, robotic production lines, and processing machinery—starting from the point of connection to the power supply; Purpose—Ensures the safety of personnel and property regarding electrical equipment in industrial machinery, as well as consistency in control response and ease of maintenance (covers safety requirements across the entire lifecycle—design, installation, operation, and maintenance—to mitigate electrical risks such as electric shock, short circuits, and fire); Content—Design reliability, wiring and grounding specifications, overcurrent/overvoltage and earth-leakage protection, emergency stop design, and periodic maintenance/inspection; Domestic Use & Export—Domestically manufactured equipment requires reference to this standard whether for export or domestic use (IEC 60204-1 is the international counterpart to GB/T 5226.1). Summary of the four key aspects: IEC 60204-1 as the core; the 2016 edition plus A1:2021; coverage of the full lifecycle of non-handheld machinery; and applicability to both export and domestic markets—ensuring a well-founded design.
II.
National Standards
What to look for in national standards?
Based on national standardization practices, the standard can be analyzed as follows: Standard Number—GB/T 5226.1-2019 *Electrical safety of machinery – Electrical equipment of machines – Part 1: General requirements* (Identical adoption of IEC 60204-1:2016; supersedes GB 5226.1-2008; issued June 4, 2019, implemented January 1, 2020; issued by the State Administration for Market Regulation and the Standardization Administration of China); Scope—GB/T 5226.1 applies to the electrical, electronic, and programmable electronic equipment and systems of machinery (including groups of machines working in a coordinated manner), excluding hand-held tools; Standard Adoption—Identical adoption of IEC 60204-1:2016; Content—Protection against electric shock and burns, protection against mechanical hazards, resistance to mechanical stress, and prevention of flame spread (covering key technical aspects); Series—Standards regarding electrical safety, indication signs, and operation (e.g., requirements for actuator location and operation; under the jurisdiction of the National Technical Committee on Electrical Systems of Industrial Machinery, TC231); Supporting Standards—GB/T 36522-2018 *General technical requirements for electrical control systems of separation machinery* (requirements for push-buttons, indicator lights, flashing lights, and touch screens follow Chapter 10 of GB 5226.1; layout and selection of emergency stop devices ensure rapid and accurate operation)—Summary of the national standard: GB/T 5226.1-2019 is currently in effect, identical to IEC 60204-1:2016, covers five categories including protection against electric shock and fire, belongs to the TC231 series, and ensures domestic compliance and implementation.
III.
Emergency Stop Safety Circuits
What to look for regarding emergency stops and safety circuits.
Based on safety control practices, the circuit should be viewed as follows: Emergency Stop—IEC 60204-1 Clause 10.7 (E-STOP Stop Category 0 or 1; hard-wired NC [Normally Closed] contact circuit; E-stop buttons must be NC; any E-stop action immediately cuts the safety circuit to stop the system); Circuit—Hard-wired safety interlock circuit (E-stop 1, 2, 3…N in series; safety relay; main power contactor; servo enable contactor; air supply solenoid valve; cutting off hazardous energy); Sensors—Critical sensor wire-break detection (safety circuit includes wire-break detection); NFPA 79—Chapter 9 (Electronic Equipment) 9.2.5.4.1.1 (E-stop circuit must be a hard-wired safety circuit; a PLC cannot be the sole means of implementing the E-stop function); ISO 13849-1—2015 Edition, Chapters 4 and 6 (safety functions must achieve the required Performance Level, PLr); Classification—Stop Category 0 (immediate power removal), Category 1 (controlled stop), Category 2 (monitored stop) (selected based on risk assessment)—Four key aspects of E-stop: hard-wired NC contacts, safety relay for energy cutoff, not solely implemented by PLC, and compliance with the required Performance Level (PLr);
these four factors ensure the reliability of the safety circuit.
IV. EU Standards
What to look for in EU standards.
In terms of EU regulatory practice, the standard is understood as follows: **Version**—EN 60204-1:2018 (European version; Safety of machinery – Electrical equipment of machines – Part 1: General requirements; BS EN 60204-1:2018 plus A1:2025 amendment); **Status**—A harmonized standard under the EU Machinery Directive 2006/42/EC (specifying detailed requirements for the design, installation, and testing of electrical equipment for machinery; failure to adhere to this standard means a declaration of conformity cannot be made, even if other parts of the machinery are compliant); **Applicability**—Applies to stationary machinery or machinery that is not hand-held during operation (including systems where multiple machines work in coordination and industrial automated robotic production line equipment); **Content**—The primary objective of the BS EN 60204 series is to minimize occupational hazards associated with operating machinery (employing best industry safety practices and ensuring safe design, installation, and maintenance of electrical, electronic, and programmable electronic equipment systems); **Differences**—Overlaps in intent with NFPA 79 but is not interchangeable (machines manufactured to NFPA 79 standards cannot automatically be installed in the EU, and vice versa; for exports to Europe, EN 60204-1 serves as the baseline for electrical equipment on machinery); **CE Marking**—Under the Machinery Directive, the electrical component is assessed according to EN 60204-1 (involving technical documentation and a declaration of conformity). In summary, regarding EU standards, consider these four aspects: EN 60204-1:2018 as a harmonized standard, the Machinery Directive 2006/42/EC, the minimization of occupational hazards, and the non-interchangeability with NFPA 79;
these four points are key to ensuring compliance for exports to Europe.
V. North American Standards
What to look for in North American standards.
Regarding US electrical code practices, the standard is defined by four key aspects: **Positioning**—NFPA 79 (Electrical Standard for Industrial Machinery; the default standard for industrial machinery in North America); **Version**—NFPA 79:2023/2024 editions (newly revised requirements effective January 1, 2026); **Scope**—Applies to electrical/electronic equipment or systems for industrial machinery (rated voltage below 1000V; starting from the power supply connection point; originated from Article 670 “Machine Tools” of the 1942 NFPA 70 National Electrical Code/NEC); **Control Circuits**—NFPA 79 Section 9.1 (powered by control transformers; transformers not required if supply voltage is ≤120V AC; control circuit voltage ≤120V AC single-phase; overcurrent protection required); **Motors**—Section 7.3.1 (motor circuit protection); **Emergency Stop**—Hard-wired safety circuit (cannot be implemented solely via PLC); **Differences**—NFPA 79 and EN 60204-1 have overlapping intent but are not interchangeable (NFPA 79 is the default for North America; EN 60204-1 is the baseline for exports to Europe). Summary for US export compliance: NFPA 79 (current edition), industrial machinery <1000V, control circuits at 120V with overcurrent protection, and hard-wired (non-PLC) emergency stops.
Conclusion
What are the electrical safety standards for non-standard assembly lines?
The conclusion is that compliance is determined across five dimensions: international, domestic, emergency stop requirements, EU standards, and North American standards.
International: IEC 60204-1 (Safety of machinery – Electrical equipment of machines – General requirements; 2016 version plus A1:2021 amendment; covers the full lifecycle of non-handheld machinery; addresses protection against electric shock, fire, and mechanical stress; and covers design, installation, operation, and maintenance). Domestic: GB/T 5226.1-2019 (identical adoption of IEC 60204-1:2016; replaces GB 5226.1-2008; effective Jan 1, 2020; managed by TC231 as part of a supporting series). Emergency Stop: Stop categories 0/1; hard-wired normally closed (NC) circuits; safety relays to cut off hazardous energy; wire-break detection; ISO 13849-1 Performance Level (PLr); NFPA 79 requirement that a PLC alone cannot implement the emergency stop function. EU: EN 60204-1:2018 (harmonized standard for Machinery Directive 2006/42/EC; minimization of occupational hazards; includes A1:2025 revision).
North America: NFPA 79 (industrial machinery under 1000V; 120V AC single-phase control circuit overcurrent protection; new requirements effective Jan 1, 2026).
Industry rule of thumb for electrical safety standards: GB/T 5226.1 (Domestic), IEC 60204-1 (International), EN 60204-1 (Europe exports), and NFPA 79 (North America exports)—mastering these four standards ensures full compliance regarding electrical safety.
