HV Work Area Barriers

Why Barriers Are Mandatory for HV Work

The requirement to secure the work area arises simultaneously from several legal sources:

• Safety rule 5 (DGUV Regulation 3): "Cover or cordon off adjacent live parts" – applies to all electrical work, including HV systems in vehicles and fixed installations
• ArbSchG §5 / BetrSichV §3: The employer must define in the risk assessment which protective measures apply at each workstation – including cordoning off the area
• DGUV Regulation 3 §3: Electrical installations and equipment must be operated in a way that third parties are not endangered

If no documented barrier procedure exists and an accident occurs, the employer bears full liability – even if a third party entered the area without authorisation.

The Most Important Single Measure: Lockout Against Re-Energisation

Before any physical barrier, the active lockout against re-energisation must be in place – directly from safety rule 2. Without lockout, all other barriers are purely symbolic.

Physical Demarcation of the Work Area

Physical barriers prevent third parties from accidentally entering the hazard zone. The appropriate type depends on the context:

Recommended minimum clearance: In practice, 0.5–1.0 m around the HV object is widely used – enough distance to prevent third parties from accidentally touching HV components, without unnecessarily obstructing operations. The exact clearance is part of the employer's risk assessment.

Warning Signs and Labelling

A physical barrier without labelling conveys no information. The following combination is widely used:

• Warning sign W012 to ISO 7010 – yellow triangle with lightning bolt: internationally understood symbol for electrical hazard, clear even for non-native speakers
• Clear wording on the sign: "HV work in progress – no entry" or "High-voltage work – authorised personnel only"
• Identify the responsible person (recommended): name or role of the responsible FHV on the sign or as a tag, so it is clear who to contact
• At least two sides of the HV object must be labelled – cover all relevant access points
• For vehicles additionally: attach a warning tag to the steering wheel or key holder, clearly visible

Who May Enter the Exclusion Zone?

Access to the cordoned-off area is tied to qualification level:

• FHV (Level 2S/2E/3S/3E): May enter the exclusion zone at any time and carry out HV work on their own responsibility
• FuP (Level 1S/1E): May only enter and work under the direct supervision and responsibility of an FHV – never independently
• All other persons (colleagues, managers, customers, visitors): entry only with explicit authorisation and under the personal control of the FHV – never unsupervised

Common Errors in Practice

Trainers consistently report the same omissions during site inspections and training courses:

• Key still in the ignition – "I'll be right back" is not a safety concept; anyone leaving the workstation must complete the full lockout
• Barrier in place, key unsecured – the visible cordon creates a false sense of security while the critical measure is missing
• No warning signs – colleagues see pylons but have no idea why the area is restricted or who to contact
• Barrier removed during short breaks – break logic does not apply to HV work; the installation must remain secured for the entire interruption
• No warning tag on the vehicle – frequently forgotten when vehicles alternate between HV work and test drives
• Barrier set too close – colleagues have to squeeze past and inevitably come within reach of the vehicle
• No documented risk assessment – even if the physical barrier is correct, there is no legal basis without a written record

Frequently Asked Questions