How to Avoid Hazardous Sparks from Arc Flashes
Failure to comply with OSHA regulations regarding electrical hazards carries a steep price – both in terms of citations issued and in employee injuries and deaths.
Over the years, electrical hazards have made a regular appearance on OSHA’s Top 10 list of safety violations. Protecting electricians and those working in the general industry from ARC flash explosions is a critical issue – one that should be taken very seriously.
OSHA and NFPA 70A require that workers are qualified in order to work on or near energized electrical systems.
Even with proper training under your belt, serious injuries can still occur. The arc flash is a phenomenon where a flashover of electric current leaves its intended path and travels through the air from one conductor to another, or to the ground. Many factors can cause this to happen, such as: dust and debris build-up, dropping tools, accidentally touching, corrosion, faulty installation, and condensation.
Arc flashes can create burns, fires, or blasting pressure depending on the proximity of the worker to the hazard, the temperature, and the time for the circuit to break. Any of these outcomes has the potential to cause severe injury or worse.
NFPA 70E Article 130.5© requires arc flash warning labels to be posted on each piece of electrical equipment that may be worked on while energized, or when validating power has been turned off.
How do we protect others from arc flash?
- De-energize the circuit (the most effective and foolproof way to eliminate shocks)
- Place Barricades around the area
- Ground Fault Circuit Interrupters (GFCI)
- Grounding (secondary protection)
- Identify hazards with signs and labels
- Develop boundaries
The National Fire Protection Association (NFPA) has established specific approach boundaries designed to protect employees while working with or near energized equipment.
What do the boundaries mean?
- Flash Protection Boundary (outer boundary): The flash boundary is the farthest established boundary from the energy source. If an arc flash occurred, this boundary is where an employee would be exposed to a curable second degree burn (1.2 calories/cm2) The issue here is the heat generated from a flash that results in burns.
- Limited Approach: An approach limit at a distance from an exposed live part where a shock hazards exists.
- Restricted Approach: An approach limit at a distance from an exposed live part which there is an amplified risk of shock.
- Prohibited Approach (inner boundary): A distance from an exposed part which is considered the same as making contact with the live part.
When are arc flash labels required?
All equipment operating at 50 volts or more, and not put into a de-energized state, must be evaluated for arc flash and shock protection. Arc flash labels provide critical safety information to workers and alert them to shock hazards, specific boundaries, and personal protective equipment (PPE) requirements.
Only “Qualified” workers are allowed to work on or near the circuit. Qualified persons have already received required training and fully display the skills and knowledge to make safe choices while conducting their work.
Having a firm understanding of the components printed on your arc flash labels is one logical way to eliminate serious injuries and unwanted trips to the hospital.