An Arc Flash is the rapid release of energy due to an electrical arcing fault, and which can have devastating consequences for anyone exposed. The arcing fault usually occurs between a phase bus bar and another phase bus bar, neutral or at ground and are also usually limited to bus voltages larger than 120V.
Appropriate PPE is an essential last line of defence for anyone exposed to Arc Flash hazard and PPE should form part of your comprehensive Arc Flash safety programme. However the selection of appropriate PPE should always be based upon the results of an arc flash incident energy analysis and subsequent arc flash risk assessment.
The required Arc Thermal Performance Value (ATPV) of PPE can only be determined following the calculation of the prospective arc incident energy. If you require these technical services we can recommend and independent company to arrange this.
Types of Arc Flash
Confined flash
Open flashThis happens when an Arc Flash occurs in a distribution box or a motor control centre. The flash is contained on all sides except the front opening of the box. All of the focused energy escapes through the only opening onto the hands and face of the person working on the box.
This happens when an Arc Flash occurs in an open space with the energy escaping 360° in all directions. The molten metal can ignite the PC and PPE of the worker.
Arc Flash Intensity
The intensity of the Arc Flash is influenced not only by the voltage. An Arc Flash will contain the release of thermal energy, acoustical energy, pressure wave and debris. The variables that affect the size and energy of an electric Arc Flash are:
- Voltage (safety issue where greater than 220 Volts)
- Amperage
- Arc Gap
- Closure Time
- Distance away from the arc
- 3 Phase v Single Phase
- Confined Space
Arc Flash Injuries
The consequences of an Arc Flash can be devastating depending on the intensity of the Arc Flash, the proximity of the individual to the source of the arc and the PPE used if any.
Injuries can include 3rd degree (irreversible) burns caused by extreme heat and molten splatter, loss of sight due to electromagnetic
radiation, internal burns and intoxication due to inhalation of hot toxic gases, permanent hearing damage due to explosion bang, and other physical trauma caused by the explosion (blast pressure and flying debris), and even death.
Protecting personnel
There are many methods of protecting personnel from Arc Flash hazards. This can include personnel wearing Arc Flash PPE or modifying the design and configuration of electrical equipment. The best way to remove the hazards of an Arc Flash is to deenergize electrical equipment when interacting with it, however de-energizing electrical equipment is in and of itself an Arc Flash hazard. In this case, one of the newest solutions is to allow the operator to stand far back from the electrical equipment by operating equipment remotely, this is called Remote Racking. By permitting the automatic racking of the circuit breaker from a remote location, it can keep the operative outside of the Arc Flash zone thereby providing a safer work environment.
We supply the latest in Arc Flash Safety equipment, including arcflash helmets, switching suits, arcflash gloves and arcflash accessories.
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