Crane Electrical Control System Safety: ISO 24617:2020 Guide
ISO 24617:2020, "Safety Requirements for Electrical Control Systems of Cranes," is the safety standard governing crane electrical control systems. It specifies safety design requirements covering protection ratings, circuit protection, emergency stop functions, electromagnetic compatibility, and selection requirements for safety PLCs.
Electrical Safety Design Requirements
ISO 24617:2020 sets out safety design requirements for crane electrical control systems. For protection ratings, control cabinets installed indoors must meet IP54, while outdoor installations require IP55. For insulation, the power circuit must have an insulation resistance of at least 1 MΩ, measured with a 500V megohmmeter, while the control circuit requires a minimum of 0.5 MΩ. In the dielectric test, the power circuit is subjected to 1500V/50Hz applied to ground for 1 minute, with no breakdown or flashover permitted. For the emergency stop circuit, the emergency stop button must comply with ISO 13850, featuring a red mushroom head with a diameter of at least 25mm. Pressing the button must directly cut power to the contactor coil, using dual-channel redundant configuration: one channel cuts power while the other triggers an alarm. The two channels operate independently, ensuring that a fault in either channel still results in a safe shutdown. After activation, the emergency stop button must be manually rotated to reset; automatic reset is not permitted.
EMC Compliance and Safety PLC Selection
Electromagnetic compatibility (EMC) requirements include radiated immunity of 30V/m across a frequency range of 80MHz to 1GHz. Electrostatic discharge (ESD) testing requires contact discharge of 8kV and air discharge of 15kV. Fast transient burst testing is conducted at 2kV/5kHz. Surge immunity requires 1kV for line-to-line and 2kV for line-to-ground. For safety PLCs, the safety integrity level (SIL) must be SIL2 or SIL3, selected based on the criticality of the crane's safety functions. SIL2 is applicable to conventional protection functions, with a safe failure rate of ≤1×10⁻⁷/h. SIL3 is required for critical safety functions such as overload protection and emergency stop, with a safe failure rate of ≤1×10⁻⁸/h. Safety PLCs must employ redundant architectures—either 1oo2 dual-channel or 2oo3 triple-channel voting—to ensure that a single-channel fault does not compromise safety functions. Any program modifications to the safety PLC must undergo validation and version management.
| safety requirements | technical indicators | application scope |
|---|---|---|
| Protection Rating (IP) | IP54(Indoor)/IP55(Outdoor) | All Control Cabinet |
| Insulation Resistance | Power≥1MΩ/Control≥0.5MΩ | All Circuits |
| dielectric test | 1500V/50Hz/1min | Power Circuit |
| emergency stop circuit | dual channelredundancy/Manual Reset | Allcrane |
| EMC | 30V/m/8kV/15kV | Electroniccontrol system |
| safety PLC | SIL2Standard/SIL3Critical | Byrisk level |
Cable and Wiring Requirements
For power cables, YCW rubber-sheathed or YZW medium-duty rubber-sheathed cables are selected for their oil and weather resistance. Control cables use KVVP shielded control cable with a conductor cross-section of at least 1.5mm². Signal cables employ STP-120 shielded twisted pair cable for sensor signal transmission. Wiring requirements mandate that power lines and control lines be routed separately with a minimum spacing of 300mm to prevent electromagnetic interference. Cables are protected within metal hose conduits, with hose fixing intervals not exceeding 500mm. Cable entry and exit points are fitted with waterproof cable glands rated to Protection Rating (IP) IP68. Kelude Heavy Industry's Electrical Control System is designed and manufactured in accordance with ISO 24617:2020.
| Cable Type | Model | cross-section | Application |
|---|---|---|---|
| Power Cable | YCW/YZW | ≥2.5mm² | Motormain circuit |
| control cable | KVVP | ≥1.5mm² | control circuit |
| signal cable | STP-120 | ≥0.5mm² | Sensor |
| communication cable | CAT5e/6 | —— | Network Communication |
FAQ
Q: What are the protection and insulation requirements for the crane electrical control system?
A: The control cabinet is rated IP54 for indoor use and IP55 for outdoor installation. Insulation resistance for the power circuit must be ≥1MΩ (measured with a 500V Megohmmeter), and ≥0.5MΩ for the control circuit. The dielectric test is conducted at 1500V for 1 minute with no breakdown allowed.
Q: What are the safety design requirements for the emergency stop circuit?
A: The emergency stop button must be a red mushroom-head type with a diameter of at least 25mm, configured with dual-channel redundancy — one channel cuts off power while the other triggers an alarm. After activation, the button must be manually rotated to reset; automatic reset is not permitted. The design complies with ISO 13850.
Q: What are the EMC test requirements for electromagnetic compatibility?
A: The system must withstand radiated immunity of 30V/m (80MHz–1GHz), electrostatic discharge of 8kV contact / 15kV air, fast transient of 2kV at 5kHz, and surge of 1kV line-to-line / 2kV line-to-ground. These tests ensure the control system operates reliably in industrial electromagnetic environments.
Q: What are the selection requirements for a safety PLC?
A: SIL2 is used for general protection functions (failure rate ≤1×10⁻⁷/h), while SIL3 is required for critical safety functions (failure rate ≤1×10⁻⁸/h). Redundant architectures such as 1oo2 or 2oo3 are adopted. Program modifications must be managed through version control. Kelude Heavy Industry's electrical control system is designed according to the standard.
