Safety of industrial trucks — Electrical/electronic requirements
1Key Takeaways
This document specifies the electrical requirements for the electrical installation design and construction of self-propelled industrial vehicles (excluding rugged terrain variable reach vehicles, straddle carriers, and all functions for automated operation of unmanned industrial vehicles) conforming to the scope of IS…
2Expert Interpretation
This article interprets BS EN 1175:2025 "Safety of industrial vehicles - Electrical/electronic requirements", covering its scope, core requirements, performance level (PLr) and technological evolution. It provides explanations of technical terms, application cases and implementation suggestions to help with compliant design and safe operation.
Standard Overview and Technological Evolution
BS EN 1175:2025 is the latest EU standard on electrical/electronic safety requirements for industrial vehicles, published in November 2025, replacing the 2020 version. This standard was developed by CEN/TC 150 technical committee and published and implemented by the British Standards Institution (BSI). Key technical changes include: updated normative references and added references to EN ISO 3691-2:2023, EN ISO 3691-3:2016, and EN ISO 3691-6:2021; revisions to the transport test specifications for contactors in Annex B; and updates to Table 5 (dielectric test voltage), etc. These changes reflect advancements in industrial vehicle electrical system technology, particularly the widespread adoption of high-voltage platforms and intelligent control systems, which place higher demands on safety performance.
Scope and Applicability
This standard applies to self-propelled industrial vehicles as defined in ISO 5053-1:2020, but excludes off-road luffing forklifts (3.21, 3.22), straddle carriers (3.18, 3.19), and the automated operation function of driverless vehicles (3.32). The standard is used in conjunction with the EN ISO 3691 series and EN 16307 series, covering all electrical/electronic components except for electrical parts, including electro-hydraulic valves. The standard does not address potentially explosive atmospheres, humidity levels below 30% or above 95%, or other extreme conditions.
This standard is based on safety function design, requiring manufacturers to determine the required performance level (PLr) for each safety function through risk assessment and to validate it according to EN ISO 13849-1:2023. This marks a shift from simple component safety to system-level safety function design.
Core Requirements Interpretation
General Requirements
The standard sets forth comprehensive requirements for electrical systems: The rated voltage of industrial vehicles must not exceed 1500V DC or 1000V AC; frame failures must not lead to dangerous movement; the protection rating of electrical cabinets must meet IPXXB (IPXXD for the top); non-insulated live parts must be protected against direct contact. Special attention should be paid to live parts with voltages higher than 60V DC or 25V AC, which must be accessed with tools.
Energy Sources and Drive Systems
Energy sources (such as lead-acid batteries and lithium-ion batteries) must comply with Annex C requirements. Lithium-ion batteries must be equipped with a Battery Management System (BMS) to provide overvoltage, undervoltage, overtemperature, and overcurrent protection, and these safety functions must achieve a PLr of Class C. Contactors must comply with Annex B, and electromagnetic contactors used in safety functions must pass rigorous testing (such as temperature, vibration, and short circuit tests).
The drive system (motor, converter, generator) must comply with Annex D, and the motor must undergo an overspeed test (1.2 times the maximum speed for 2 minutes). The driving and braking control system adopts the "safe state" concept: no driving torque, automatic braking, or automatic deceleration. Operator presence monitoring (OPC) requires the drive system to enter a safe state within 2 seconds when the operator leaves the normal operating position (speed control release reduces to 0.2 seconds). Forklift acceleration control must be started from neutral to prevent accidental movement. For runaway acceleration, Table 1 provides permissible thresholds (e.g., acceleration not exceeding 75% of maximum acceleration within 0.2 seconds). The automatic parking brake must prevent accidental release and alert the operator in case of malfunction. Speed limiting functions (e.g., turning, working at height, platform folding, etc.) must meet the corresponding PLr (e.g., stacker high-speed lateral stability limit requirement PLr=c).Electrical Load Handling System (LHS)
LHS must start from neutral and stop within 2 seconds when the operator leaves. The load clamping device must double-act to prevent accidental release. Limiting functions (such as tilt angle, forward movement) must achieve PLr=c if used for stability verification.
Steering System
Pure electric steering (without backup) must detect and control a stop within 0.1 seconds when a single fault causes unexpected steering, PLr=d. With backup steering, the backup is automatically activated and a warning is issued after a fault (PLr=c). When electric power steering fails, the path should be maintained and a warning should be issued (PLr=a).
Performance Level (PLr) Comparison Table
| Safety Features | Counterweight Forklift | Walking Pallet Truck | Operator Lift |
|---|---|---|---|
| Driving Control System | c | b | c |
| OPC Monitoring | b | b | c |
| Turning Speed Limit | c | - | c |
| Electronic Brake Control | c | c | c |
| Automatic Parking Fault Indication | a | a | a |
| Unexpected Acceleration (Stationary) | c | b | c |
| Steering Without Backup | d | - | d |
Note: PLr increases from a to e, with a being the lowest and e being the highest. "-" in the table indicates that it is not applicable.
Key Terminology Explanation
Safety Function: A machine function whose failure may result in an immediate increase in risk.
Explanation of Key Terms
Safety Function: A machine function whose failure may result in an immediate increase in risk.
Explanation of Key Terms
Safety Function For example, Operator On-Site Detection (OPC) is a safety function. **Required Performance Level (PLr):** Based on the performance level determined by the risk assessment for each safety function, it is divided into five levels from A to E. The higher the PLr, the more stringent the requirements for system redundancy and diagnostic coverage. **BMS (Battery Management System):** Monitors battery status and prevents overcharging, over-discharging, and overheating; it is a core safety component of lithium-ion batteries. **Practical Application Cases:** Case 1: Operator On-Site Detection (OPC)** On a counterbalance forklift, a sensor under the seat acts as the OPC. When the operator gets up, the sensor disconnects, and the controller cuts off the drive and applies the brakes within 2 seconds to avoid the danger of unattended operation. If the operator simultaneously releases the accelerator pedal, the delay is reduced to 0.2 seconds, ensuring a rapid stop. **Case 2: Automatic Parking Fault Indication** A certain model of forklift is equipped with an electronic parking brake. If the controller detects that the brake has not been released or the sensor malfunctions, the instrument panel immediately displays a warning light (PLr=a), reminding the operator to intervene manually. Simultaneously, the braking system remains in a de-energized braking state to prevent slippage. Implementation Recommendations Manufacturers should: 1) Design safety functions based on the PLr requirements in the standard (Tables 2, 3, 4, 6) and adopt the verification process of EN ISO 13849-1:2023; 2) Add insulation monitoring and emergency disconnect devices for high-voltage vehicles (>120V DC); 3) Ensure that software design follows modularity and diagnostic coverage requirements. Users should: 1) Specify the safety function check cycle in the operation manual; 2) Observe warning lights and check OPC and braking functions during daily use; 3) Refer to electrical diagrams during maintenance and strictly prohibit arbitrary modification of parameters. Special Note: For lithium-ion battery forklifts, a matching BMS and charger must be used; otherwise, thermal runaway may occur. It is recommended to perform system-level safety integrity verification before actual deployment. This interpretation provides technical analysis based solely on the standard text; actual application requires consideration of the latest regulations and specific product conditions.