What operations need to know about servicing high-voltage equipment
10 July 2025 
As more heavy-duty forklifts adopt high-voltage electric power, operations must understand the servicing and safety requirements. From certification levels to shared responsibilities under EN 50110, proper training, procedures, and precautions are critical to maintaining safety and compliance when working with high-voltage material handling equipment. Ricky Hirani, Global Commercial Product Leader, Big Trucks & Port Equipment, for Hyster explains further
Heavy-duty forklifts are increasingly powered by electric sources like batteries, rather than internal combustion engines (ICE). To achieve the charging speed and power delivery required by applications with demanding duty cycles and heavy loads, this high-capacity electric material handling equipment relies on high-voltage battery systems.
Not all electric materials handling equipment uses high-voltage batteries. For example, a 4,000-pound, or 2,000-kilogram, capacity counterbalanced forklift with an integrated lithium-ion battery might use a dual voltage battery that can operate at 48 or 96 volts (V). However, for equipment that does use highvoltage battery systems, there are important safety considerations.
Electrical safety responsibilities
The European Committee for Electrotechnical Standardisation (CENELEC) defines the EN 50110 standard. It defines a shared responsibility for electrical safety. The owner of the premises where equipment is being maintained or serviced, their equipment dealer and the manufacturer all need to work together with a shared interest in the safety of work being performed.
Training and certification requirements
While it’s very common for operations with materials handling equipment like forklifts to service their own equipment, maintenance or repair work on high-voltage circuits, often identified by orange cables, requires individuals who are certified to work with these kinds of systems. EN 50110 identifies three levels of certification, identifying the technical knowledge required by individuals in order to work with high-voltage equipment and requiring individuals to be recertified every three years.
*Electrical instructed person (EIP, also known as VOP/EUP)
One who is allowed to pull the master service disconnect (MSD) but not to measure 0-volt in the system. They assist the high-voltage technician (HVT) in working on high-voltage components and are able to assess the risks of the task at hand and deny work if in doubt about the situation
*High-voltage technician (HVT, also known as VP/EFK)
One who is allowed to pull the MSD and allowed to measure 0-volt in the system. They are able to work on high-voltage equipment independently or with the help of an EIP. They must understand when procedures are not clear and are able to consult with the high-voltage work supervisor (HVWS).
*High-voltage work supervisor (HVWS, also known as WV/VEFK)
One who is responsible for defining procedures and seeing to it that procedures are followed.
In addition to electrical certification, individuals must also have training and certification specific to the materials handling equipment they will be working directly with.
What does this mean for operations?
Businesses need to be aware of these requirements so that they only allow individuals with proper certification to participate in maintenance or repair work that requires specialised training. They should also confirm that their authorised dealer’s technicians are current on the certifications required.
Two technicians are required when disconnecting and reconnecting high-voltage systems: one technician working on the truck and another in a support role to immediately intervene if necessary.
While it is essential that only certified individuals are engaged in work that requires such certification, not all work on this equipment, like changing windshield wipers or light bulbs, requires certification. Maintenance or repairs on systems that are not powered by high-voltage circuits may not require technicians who are certified in electrical safety. This could include components such as:
- Parts of the operator compartment
- Mast
- Some hydraulic components
- Parts of the cooling system
- Carriage
- Wheels and tyres
Operations and their technicians should carefully review the service manual for the particular forklift or container handler they plan to conduct service or maintenance on to understand whether certified individuals are required for specific work
USED FOR MAINTENANCE AND REPAIRS
Master Service Disconnect (MSD) Also referred to as a manual service disconnect, the truck MSD breaks the series connections within the battery, making the contactor connections to the motor inactive. Using the MSD is typically the first step for shutting down and securing a high-voltage circuit in the truck. Rubber gloves and other prescribed PPE must be worn when pulling the MSD, which is usually located behind an unlocked door on the truck and marked with a triangle decal with a flash or lightning bolt symbol.
High-Voltage Interlock Loop (HVIL) This continuous low-voltage wire runs through all of the high-voltage connections in the system to monitor the integrity of the circuit and the security of all high-voltage covers. If the loop is broken because the MSD has been pulled or a cover is open, this system disables the contactors so they cannot engage and the high-voltage system is not activated
RUNNING CONTINUOUSLY FROM TRUCK KEY-ON
Ground Fault Detection (GFD) High-voltage wire has a metal shield that is connected to the truck. When there is an abrasion on the wire, the ground fault detection senses it and disconnects the truck, triggering a fault code so that operation of the truck is halted until the issue has been resolved.
Power Enable Loop (PEL) This software monitors the temperature and voltage in a battery module. When a battery module goes out of its rated temperature or voltage range, the power enable loop opens and that battery is disabled to allow it to return to an appropriate temperature or to allow the voltage imbalance to be corrected.
Why go electric?
Pressure is mounting to significantly reduce greenhouse gas (GHG) emissions and accelerate the transition from fossil fuels to renewable energy sources, and regulatory requirements are growing.
There is also a variety of benefits that can make electric-powered materials handling equipment an attractive solution. Battery electric forklifts produce zero tailpipe emissions. Compared to ICE models, electric alternatives produce less noise and vibration, offering a more comfortable experience for the operator.
Electric equipment can also be less expensive to maintain. For example, diesel engines require regular oil changes, usually every 500 or 1,000 hours of use, with each typically requiring multiple gallons or litres of costly oil. Not only are oil changes eliminated, but electric equipment reduces or eliminates many of the other extensive service requirements associated with ICE equipment for the engine, fuel and air filters, transmission and brakes.
And as emission standards for ICE equipment get more stringent, there is more emissionsrelated equipment on ICE trucks to maintain, such as the diesel particulate filter (DPF), diesel exhaust fluid (DEF) system and exhaust gas recirculation components. Because of the reduced components of electric equipment, servicing a high-voltage truck can be less expensive in some cases than ICE alternatives.
High-voltage battery systems are used on heavy-duty equipment like high-capacity forklifts because of physical equipment design considerations, and because they offer productivity benefits that can be advantageous for some operations. From a design perspective, to achieve the necessary power using lower voltage wires, the wires would be thick and heavy enough that their bend radius would not allow them to fit within the frame of the truck. In terms of productivity, higher voltages allow for faster charging compared to lower voltage systems and provide very responsive performance.
For further information please visit: www.hyster.com