Principe of any electrical safety mitigations is also principle of arc flash hazards & risks mitigation solution. Basic principle of arc flash mitigation is about how to reduce incident energy or arc energy reduction. Arc flash mitigation solution is protecting people and assets, reducing the cost of injuries and damage, limiting downtime and maintenance requirements. —Omazaki Consulant is a consultant provides arc flash hazard study and assessment service. We also will provide recommendation to mitigate arc flash hazards. Contact us if you are looking for consultants who provide practical arc flash hazards mitigation solution for your electrical systems in Indonesia and South East Asia by sending an email to cs@omazaki.co.id or by filling in the form in contact.
Arc Flash Hazard Hierarchy of Risks Control
Arc flash incidents are rare. But, arc flash incident has the highest mortality rate of any accidents in electrical installations. Arc flash hazards mitigations have to reduce impact on human, minimize equipment damage and reduce the effect of arc flash and arc blast as well.
As per NFPA 70E Sec. 110.3(H)(3), there are six steps in arc flash hazards hierarchy of controls:
| Steps |
Description |
Explanation |
Examples |
|
1 |
Elimination | Removes the cause of danger or hazards completely | Difficult to achieve |
|
2 |
Substitution | Replacing a severe hazard with a less severe one | Insulated bus, smaller transformers, arc-resistant gear, current-limiting fuses |
|
3 |
Engineering control | Replacing equipment or changing the work environment to separate workers from a hazard | Current-limiting devices (fuses, neutral-grounding-resistors), arc-flash relays, maintenance/ instantaneous trip |
|
4 |
Awareness | Educating workers on the hazards and providing information on making safe decisions |
|
|
5 |
Administrative control | Developing formal procedures and processes for working safely under anticipated conditions |
|
|
6 |
Personal Protective Equipment (PPE) | Require and equipping workers with clothing and equipment designed to reduce risk and limit the severity of injuries | Provide arc flash PPE according to incident energy category |
NEC Article 240.87 Arc Energy Reduction
Based on National Electric Code (NEC) 2017 article 240.87 there are several method to reduce arc energy:
- Zone-selective interlocking
- Differential relaying
- Energy-reducing maintenance switching with local status indicator
- Energy-reducing active arc flash mitigation system
- An instantaneous trip setting that is less than the available arcing current
- An instantaneous override that is less than the available arcing current
- An approved equivalent means
Arc Flash Mitigation — Engineering Solutions
There are various technical solutions proposed by various manufacturers of electrical distribution devices in the world. In this article we adapt the concept of arc flash mitigation solutions developed by ABB(4) .
|
Passive Arc Flash Mitigation |
Protect by containing or preventing an event.
Switchgear designed and tested to mechanically withstand the electric arc. Protection is afforded by the containment of the arc within the switchgear and the means to direct the arc gases and debris to a safe area. |
| Active Arc Flash Mitigation
|
Reduce equipment damage and improve operator safety.
Switchgear equipped with devices and solutions to limit the arc incident energy (the amount of thermal energy generated during an electric arc event) and consequently limit the damage to the equipment |
| Preventive Arc Flash Protection
|
Avoid internal arc events
Switchgear equipped for remote operation, so that standard operations such as switching, diagnostic and operational monitoring, racking in/out, etc. |
There are others practical mitigation solutions to arc flash hazards.
Contact Omazaki Consultant if you are looking for arc flash solution, or arc flash hazard and risks mitigations techniques consulting service to reduce arc energy or incident energy reduction in your electrical system in Indonesia and South East Asia, both existing and planning systems.
Related Articles
- Arc Flash: Definition, Hazards and Risks
- Arc Flash Causes & Location
- Arc Flash Calculation Methods
- Arc Flash Boundary and Requirements of Personal Protective Equipment (PPE)
- Arc Flash Hazard Study and Assessment
- Electric Shock Protection Study
- Short Circuit Study and Analysis
- Protection Coordination Study & Analysis
References
- NFPA 7o – National Electrical Code (NEC)
- NFPA 70E – Standard for Electrical Safety in the Workplace
- IEEE 1584 – IEEE Guide for Performing Arc-Flash Hazard Calculations
- ABB – Smarter Safety Arc Flash Mitigation Solutions for Greater Protection and Productivity