What is electrical risk and how does current act?
The effects of electric current on the human body depend on the intensity, the duration of the current flow, its path, frequency, and the resistance of the body and any contacts. Intensity is the determining factor: thresholds for perception, the ability to hold on, and ventricular fibrillation increase, reaching only a few milliamperes in alternating current at 50 hertz. Voltage influences the effects through Ohm’s law and the body’s resistance, which decreases with humidity and the surface area of contact; therefore, regulations establish safety voltages and prescribe protective measures based on the specific conditions of the premises.
In addition to physiological effects (tetanization, respiratory arrest, fibrillation, internal and external burns), electric arcs cause radiation burns and burns from molten metal projection, and short circuits can start fires or explosions in flammable atmospheres. Falls from heights caused by electric shock are a frequent cause of serious injury.
Royal Decree 614/2001 applies to all electrical installations in workplaces and to the techniques and procedures for working on them or in their vicinity. It is complemented by the Low Voltage Electrotechnical Regulation (Royal Decree 842/2002) and the Regulation on technical conditions and safety guarantees in high voltage electrical installations (Royal Decree 337/2014), which regulate the design, execution, and maintenance of these installations.
Essential content of Royal Decree 614/2001
- Electrical installations (Article 3 and Annex I). The type of installation and its characteristics must be adapted to the conditions of the premises and the activity; the installations must be used and maintained properly and checked periodically.
- Techniques and work procedures (Article 4). All work on an electrical installation shall be carried out without voltage, except for the exceptions provided; live work, maneuvers, measurements, tests and verifications, and work in proximity shall be carried out in accordance with Annexes II to V.
- Work without voltage (Annex II). The five golden rules: disconnect, prevent any possible feedback, verify the absence of voltage, ground and short-circuit, and protect against nearby live elements and mark the work area; the restoration of voltage follows the reverse order.
- Live work (Annex III). Only by qualified workers, with written procedures, suitable equipment and materials and, at high voltage, with specific authorization; they cover working methods at potential, at a distance and in contact.
- Maneuvers, measurements, tests and verifications (Annex IV). Carried out by authorized workers and, in high voltage, qualified workers, with safety equipment and limiting the risk of arc flash.
- Proximity work (Annex V). Reduce or eliminate the danger zone with screens, enclosures or insulating protectors; delimit the work area and, if necessary, supervise by an authorized or qualified worker; includes work with mobile equipment near overhead lines.
- Sites with risk of fire or explosion and static electricity (Annex VI). Specific measures to prevent electricity from being a source of ignition.
- Training and information (Article 5). Workers must receive appropriate training and information; the categories of authorized and qualified worker are defined in Annex I.
Prevention and protection measures
- Protection against direct contact. Isolation of live parts, barriers or enclosures, obstacles and distance, and complementary protection with high sensitivity residual current devices.
- Protection against indirect contact. Grounding of exposed conductive parts associated with fault current cutting devices, double insulation, electrical separation and safety extra-low voltage.
- Work equipment. Insulated tools, equipment with the appropriate level of protection, compliant extension cords and construction panels, periodic verification and removal of damaged equipment.
- Personal protective equipment. Insulating gloves, footwear, arc flash face shields and flame-resistant clothing depending on the work and voltage.
- Organization. Written procedures, facility lockout/tagout, work permits, designation of authorized and qualified workers, and coordination with external companies.
Organizational application: how to manage electrical risk
- Inventory the electrical installations of the center with their documentation, regulatory inspections and maintenance status.
- Evaluate the electrical risk by installation, activity and type of work (without voltage, on voltage, maneuvers, proximity), including work with mobile equipment near overhead lines.
- Define in writing the work procedures, energy isolation and permits, and formally designate the authorized and qualified workers.
- Train and inform according to Annex I and record the training and designation by person.
- Provide adequate work and protective equipment, with periodic verification of gloves, poles, detectors and grounding equipment.
- Coordinate with external companies involved in facilities or in their vicinity.
- Investigate electrical incidents, including those without damage, and review procedures.
Preventive management software allows you to manage designations, training, protective equipment inspections, work permits and assignments with traceability and expiration alerts.
Limits and common mistakes
- Working under voltage without complying with the conditions of Annex III or without qualified personnel, claiming urgency or brevity of the intervention.
- Omitting the verification of absence of voltage or grounding and short-circuiting when applying the golden rules.
- Confusing the categories of authorized and qualified worker and assigning tasks beyond the level of training.
- Ignore work in proximity to overhead power lines using cranes, platforms, or vehicles.
- Using personal protective equipment without the required periodic checks.
- Citing the royal decree with an incorrect year; the current regulation is Royal Decree 614/2001, of June 8.
Safety distances, limit voltages and conditions for each type of work should be consulted in the annexes of the royal decree and in the INSST technical guide.
Practical example
Situation: An industrial maintenance company needs to replace a switch in a low-voltage panel at a customer plant.
- Planning. Work without voltage; work permit coordinated with the plant, identification of the circuit and possible backfeeds.
- Execution. Disconnection, lockout and labeling, verification of absence of voltage with a tested detector, grounding and short-circuiting where appropriate, marking of the area.
- Personnel. Authorized worker with registered training, verified insulating gloves, and insulated tool.
- Closure. Restoration of power in reverse order, removal of the lock by the person who placed it and recording of the work.
Regulatory framework in Spain
- Royal Decree 614/2001, of June 8. Minimum provisions for the protection of the health and safety of workers against electrical risk.
- INSST technical guide on electrical risk . Criteria for the application of Royal Decree 614/2001.
- Royal Decree 842/2002, of August 2. Electrotechnical regulations for low voltage and supplementary technical instructions.
- Royal Decree 337/2014, of May 9. Regulation on technical conditions and safety guarantees in high voltage electrical installations.
- Royal Decree 1215/1997, of July 18. Use of work equipment, including electrical equipment.
Directive 89/391/EEC and Directive 2009/104/EC constitute the general European framework; electrical risk does not have a specific directive and each Member State regulates the installations and the work on them.
