Arc Flash NFPA 70E & IEEE 1584 Studies
An arc flash hazard analysis is an electrical engineering study to:
- Determine the risk of personnel injury as a result of exposure to incident energy (IE) released during an arc-flash event
- Provide recommendations for appropriate arc-flash hazard protection
- Inform the personnel about the existing arc electrical safety.
- Comply with OSHA, NEC, and NFPA 70E requirements
Based on the results of an arc-flash hazard analysis, the rating of personal protective equipment (PPE) such as gloves, flame-retardant shirts and pants, eye protection, etc can be properly selected for adequate personnel protection. Arc flash labels with this information will be provided as a part of this study.
The recently published NESC-2012, Rule 410 A(3) requires:
- An Assessment of Potential Electric Arc Exposure
- PPE Required If IE >2 cal/cm2 (2rd Degree Burn Threshold)
- Wear PPE Clothing or System W/ Effective Arc Rating (EAR) NLT Anticipated IE Level
- Can Not Wear Acetate, Nylon, Polyester, or Polypropylene
- Clothing EAR ?1000 V TBD By NESC Tables or AFHA
The assessment can consist of an arc flash study with IE calculation based upon available fault current (AFC), arc duration, and working distance or can use NESC Tables 410-1 and 410-2 In Lieu of arc flash study.
Our concerns with using NESC Tables 410-1, 410-2, and 410-3 are:
- What If Actual AFC Differs Significantly From Tables?
- What If Actual Clearing Time Differs Significantly From Tables?
- What About the Arc Blast Factor?
OSHA 29 CFR 1910.132(d) requires employers to assess the workplace to determine if hazards are present or likely to be present, and select and have each employee use the types of PPE that will protect them. Employers are also required to verify that the required workplace hazard assessment has been performed through a written certification that identifies the particular workplace evaluated.
Arc Flash Study Steps
Do you know the seven (7) major steps involved in an electric arc flash hazard Study?
According to IEEE-1584, they include:
- Data Gathering
- Power System Modeling
- Short Circuit Analysis
- Overcurrent Protective Device Coordination
- Arc Flash Study
- Label Installation