What to do Between Now and Your Arc Flash Analysis (Part III)

As mentioned, using the NFPA 70E 130.7 chart properly isn’t really a viable solution for either short term or long term. If a company wants to use the NFPA 70E 130.7 chart in a compliant way, they are running into the same problems as completing an arc flash analysis; time and money. So, in consideration of not being able to use the 130.7 chart to be compliant and having a gap in time before an arc flash analysis can be completed due to funding or other issues, many companies are left in limbo on what to do.


The following steps are suggestions to help protect your workers in the interim, get a program in place and start working towards completing an arc flash analysis:

1. Determine Hazardous Tasks Workers will do and Include in Documentation of Electrical Safety Plan

If you do not already have an electrical safety plan developed and documented, this should be done first. This plan will define how electrical systems are designed, maintained and managed including guiding both management and workers how to work on and around energized equipment in your plant or facility (see chart in Appendix for all information that should be included in your plan).

Part of this plan would include how workers should approach or work on energized equipment in absence of proper warning on the arc flash hazard category. A suggested plan would be as follows:

1. Using the NFPA 70E 130.7 charts, one can determine what combinations of voltage / equipment / tasks would require Cat 3 or 4 PPE based on the assumptions (see chart in Appendix). Based on this, the employer makes a determination if any of these tasks are something:

       A. Their workers are qualified to do, perform and want to continue doing

       B. Their workers are not qualified to do, perform or something that represents a risk that they do no want their workers exposed to and therefore, will outsource.

2. If the combination of voltage / equipment / task being performed is something that the customer will be doing internally, immediately invest in 1 - 2 sets of Cat 4 kit to handle those Cat 3 & 4 situations

3. If the combination of voltage / equipment / task being performed represents something that the employees do not do, are not qualified to do or represents a risk that the employer does not want employees taking, outsource those tasks to a qualified electrical contractor. From a liability standpoint, you should clearly advise the contractor that based off of the NFPA 70E 130.7 charts, this represents at least a category 3 or 4 hazard and they should take proper precautions.

2. Invest in Appropriate PPE

          1. Invest immediately in Cat 2 PPE*. After an arc flash analysis is done, the results typically show that the vast majority (and sometimes all) of the panels are rated Cat 0 – 2. Based on this outcome, employers typically end up putting all their workers in Cat 2 PPE as that covers all or nearly all the work they will be doing and is reasonable equipment to work in and purchase.

          2. Invest in Cat 4 PPE kits if the determination from step 1 is that the workers will be working on hazard categories 3 or 4 based on the NFPA 70E 130.7 Chart.

* The danger in this practice is that there are situations that under the assumptions made for the NFPA 70E 130.7 Chart will determine the risk hazard category as 0,1 or 2 when in reality, it could be a category 3, 4 or above category 4. A different than assumed short circuit current available or longer fault clearing can increase the hazard. This information can only be known, however, but doing an arc flash analysis.

          3. Set Approach Boundaries

NFPA 70E 130.3 (A) (1) defines the default arc flash boundary to be 4 feet for voltage levels between 50 volts and 600 volts the clearing time and the fault current do not exceed 100 KA cycles. Without doing an actual analysis, it’s virtually impossible for someone to determine if their equipment will not exceed 100 KA cycles and require a bigger approach boundary. In lieu of having the proper information to set the boundaries, a 4 foot boundary as a temporary means is suggested.

           4. Train Workers

1. Train those who would be working on or around energized equipment about Electrical Safety and Arc Flash (see Appendix for training outline). Part of this training includes specifics on PPE and tasks, including:

         Only perform the tasks allowed by NFPA 70E (i.e. troubleshooting) on energized circuits. Any other work on energized circuits requires a hot work permit which includes the results of an arc flash analysis and the defined arc flash protection boundary. It must be noted that even troubleshooting is not immune to arc flashes. Tasks as simple as voltage measurements and current probes can result in arc flashes.

A. How to properly identify equipment, voltages and tasks and understand their hazards

B. How to apply that knowledge to using the * NFPA 70E 130.7 charts, including the shortcomings of the chart

C. Crossover information from OSHA or local standards and the NFPA 70E 130.7 Chart for PPE

D. How to properly use the PPE equipment for tasks they are qualified to do and approved to do by their employer

E. How to properly recognize situations they need to avoid and outsource per directions of their employer

These suggestions are a short-term stop-gap approach to protecting your workers until an arc flash hazard analysis being completed, but it is in no way a permanent solution to protecting workers from electrical arc flash hazards nor is it considered compliant with OSHA or NFPA 70E.  Martin Technical maintains that nothing short of doing an arc flash analysis is properly warning workers of hazards or being in compliance with OSHA and NFPA 70E as it relates to arc flash hazards.