What is IEC 60947?
IEC 60947 is the international standard for low-voltage switchgear and controlgear in industrial applications. The standard defines technical requirements for components such as switches, motor protection devices, contactors, relays, fuses and miniature circuit breakers up to 1000V AC or 1500V DC.
In OT environments, IEC 60947 forms the technical basis for safe and reliable switching, protection and control of electrical installations in machines, switchboards and control panels.
🧠 Purpose of IEC 60947
- Protecting people and installations from electrical hazards
- Standardising performance and test criteria for components
- Simplifying integration and compatibility
- Supporting CE marking and ATEX applications
- Ensuring continuity in switching and drive operations
🔧 Subdivision of the standard
| Part | Description |
|---|---|
| IEC 60947-1 | General definitions, test methods and requirements for all parts |
| IEC 60947-2 | Circuit breakers and miniature circuit breakers |
| IEC 60947-3 | Disconnectors, load-break switches, isolating switches |
| IEC 60947-4-1 | Contactors and motor starters for asynchronous motors |
| IEC 60947-5-1 | Control and auxiliary switches (e.g. push buttons, relays) |
| IEC 60947-5-2 | Sensors with switching output (e.g. inductive, capacitive) |
| IEC 60947-6-2 | Multi-function devices (e.g. motor protection switches) |
These parts are often combined in control cabinets in line with IEC 61439 or machine panels in line with IEC 60204-1.
📦 Typical IEC 60947 components in OT environments
| Component | Use |
|---|---|
| Power circuit breaker | Short-circuit and overcurrent protection of supplies/motors |
| Contactors | Switching motors and loads remotely |
| Motor protection switch | Thermal-magnetic protection plus switching function |
| Emergency stop relay | Safe shutdown on faults or emergencies |
| Sensor with PNP/NPN output | Object detection in production or conveyor lines |
✅ Why IEC 60947 matters
| Benefit | Description |
|---|---|
| Standardised specifications | Compatibility and interchangeability between brands |
| Tested switching functions | Operating cycles, short-circuit withstand, electrical service life |
| Safe operation | Designed and tested for industrial loads |
| CE conformity | Supports product certification and machine safety |
| Applicable in Ex zones | Some components are Ex-certified in combination with IEC 60079 |
🔁 IEC 60947 and related standards
| Standard | Relation to IEC 60947 |
|---|---|
| IEC 61439 | Switchgear cabinet standard incorporating IEC 60947 components |
| IEC 60204-1 | Machines must use safe switches in line with 60947 |
| ISO 13849-1 | Safety components must achieve reliable switching levels |
| NEN 1010 | Installation standard – references 60947 for technical requirements |
| IEC 60079 | Ex-zone applications require 60947 components with Ex approval |
⚠️ Common practical mistakes
- Use of unsuitable contactors for frequent starting/stopping
- No selective coordination between circuit breaker and motor protection
- Over- or under-dimensioning of switches (Icu/Ics)
- Failing to verify the short-circuit withstand of the entire switching chain
- Incorrect application of PNP/NPN sensors without logical verification
📌 In summary
IEC 60947 is the backbone of all industrial switching below 1000V. In OT environments, compliance ensures safe, standardised and fault-tolerant electrical installations.