Why Regular Arc Flash Studies Are Important

Nov. 27, 2017
Most companies rely on a standard five-year update model for their arc flash studies, but a better method is to be more proactive with ongoing updates and standards.

NFPA 70E recommends verification of a site’s arc flash study every five years. But what happens in between those years with 2015 NFPA 70E 130.5? Many facilities are making updates to their electrical system on a weekly basis, including motor replacements and additions, new panel boards, resizing disconnects and small equipment, and numerous other changes. What is the NFPA expectation and intent for how often an arc flash study should be revised?

According to a panel of advisers working on approval for the 2018 NFPA 70E code changes, it should always be up to date. This directly contradicts the way most companies arrange their safety updates—as well as the way most firms are set up to provide arc flash studies.

Now that we know the intent of the code regarding how arc flash studies are to be maintained, how can it be done practically? First, the standard five-year update model is one that effectively requires a complete redo of the original arc flash study. There are very few sites that have well-documented and/or minimal changes, so the cost of an update is likely to be very similar to the initial study. The better method is to follow a more rigorous documentation and update standard for new work and either partner with a firm that provides arc flash studies or have a dedicated in-house professional. So how do you ensure that you have what you need to be more proactive? Ask yourself the following questions when getting an arc flash study done:

Do I own my arc flash model? If you are not provided the model, you will effectively be locked into the contractor who did the arc flash study. If you have another firm perform electrical work on site, they will have to start from scratch, which will add cost to the update.

Am I getting a set of drawings that can be marked up and maintained accurately? In addition, there are some questions you want to make sure you think of when you are going to have electrical work done on site to make the updates as accurate as possible:

  • Am I getting updated drawings from this work?
  • Will existing drawings be updated to accurately represent the work done?
  • Has an arc flash update been included as part of the work?
  • Will I be provided arc flash tags consistent with NFPA requirements for any new or replaced equipment?

In the end, the goal would be to have any electrical updates performed on site to have all relevant documentation updates performed at the time of work and to have the arc flash study updated before or shortly after the installation is complete. It is important to remember that with NFPA 70E, you will be held to your own interpretation of the code as it is documented in your own safety procedures.

Chris Meyers is electrical engineer at Interstates Control Systems Inc., a certified member of the Control System Integrators Association (CSIA). For more information about Interstates Control Systems, visit its profile on the Industrial Exchange.