Quick Answer: Any qualified electrical engineering firm can update an arc flash study that another company completed, as long as it verifies the existing data, checks the system in the field, and recalculates incident energy using the current IEEE 1584 method. Bowtie Engineering reviews existing studies and delivers updated labels, one-line diagrams, and a full engineering report, with the work led by licensed Professional Engineers. Call 866-730-6620 to talk through your current study.
Many facilities end up with an arc flash study done by a firm they no longer work with. The original engineer may have retired, the company may have moved on, or you may simply want a new partner for the next update. The good news is that you are not locked in. This article explains who can take over an existing study, what to hand over, what changes when a new engineer picks it up, and what you should receive at the end.
Can a Different Engineering Firm Update My Arc Flash Study?
Yes. A different engineering firm can take over your arc flash study and bring it up to date. The new firm will typically:
- Review the original report, model, and assumptions
- Verify in the field that installed equipment matches the model
- Recalculate incident energy using the current IEEE 1584 method
- Issue new labels, updated one-line diagrams, and a new engineering report
NFPA 70E requires the arc flash risk assessment to be reviewed at least every five years and updated whenever a major modification or renovation takes place, so the update has to happen no matter who did the first one. Bowtie Engineering performs arc flash and incident energy studies led by licensed Professional Engineers, and its engineers review existing studies as part of that work.
What Information Does a New Firm Need From the Old Study?
A new firm needs as much of the original data as you can find, because the more complete the handoff, the less field time the update needs. Gather the following before you request a quote:
- The final study report, including the modeling assumptions
- The software model file, if the original firm will release it
- One-line diagrams, marked with any changes made since the study
- The utility fault current data used in the original calculations
- Protective device settings and coordination data
- A list of equipment added, removed, or replaced since the study
- Photos or copies of the current arc flash labels
If some of this is missing, the study can still be updated. The engineer will collect more data in the field to rebuild whatever is not available.
Do I Need to Start the Study From Scratch?
Not always. The deciding factor is how much the engineer can trust the existing data:
- An update is usually enough when the original data is solid, the one-lines are current, and the system has changed little.
- A fuller rebuild is safer when the original data is incomplete, the one-lines are out of date, or the study used an older calculation method.
An engineer should not stand behind labels built from information they cannot verify. A good provider will tell you plainly which path your study needs, and why, before the work starts.
Does the Software the Original Firm Used Matter?
It can, because model files do not always move cleanly between power system modeling programs. Bowtie Engineering works in SKM, EasyPower, and ETAP, which covers the platforms most often used for industrial studies. Even when a file opens without trouble, the engineer still needs to check:
- Device libraries and protective device settings
- Cable lengths, sizes, and conductor data
- Transformer and utility source data
Software makes the math fast, but accurate field data is what makes the answer right.
Why Might Updated Labels Show Different Numbers?
Updated labels often show different incident energy values because something real has changed. Common reasons include:
- New or replaced equipment, transformers, or feeders
- A change in available fault current from the utility
- Different protective device settings
- A newer calculation method
The IEEE 1584 standard for arc flash calculations was revised in 2018. The newer method accounts for factors such as electrode configuration and enclosure size, so a study done under the older method can produce noticeably different results once it is recalculated. Higher numbers do not mean the previous firm made a mistake. They show the hazard more accurately, and your PPE and work practices should follow the new values.
How Long Does an Arc Flash Study Update Take?
Timing depends on the size of the system and the quality of the existing documentation:
- For a full study, Bowtie Engineering reports that a facility with 500 or fewer buses typically takes four to six weeks from start to finish.
- An update with good existing data can move faster.
- A projected timeline comes with the quote.
If you are unsure whether your study is due, read how often an arc flash study should be updated for the most common triggers.
What Should You Ask a Firm Taking Over Your Study?
Ask questions that show how the new firm will handle data it did not collect:
- Will a licensed Professional Engineer lead the study?
- How will you verify the existing data in the field?
- Which IEEE 1584 edition will you use for the calculations?
- Can you work with our existing software model, and if not, how will you rebuild it?
- Will we receive updated one-line diagrams and a full engineering report, not just labels?
What Does Bowtie Engineering Deliver After an Update?
Bowtie Engineering delivers a complete set of documents your team can use as soon as the work is done:
- Arc flash labels showing calculated boundaries, incident energy values, and required PPE
- Accurate, updated one-line diagrams
- A full engineering report covering modeling assumptions, fault current calculations, and protective device coordination
- PPE guidance tied to the study’s actual values
Bowtie Engineering also labels equipment below 1.2 cal/cm², which goes beyond the NFPA 70E minimum. For service-contract clients, the results load into BowVue alongside maintenance records and the qualified worker list.
Frequently Asked Questions
Will the original firm give me the software model?
Practices vary from firm to firm. Ask in writing for the model file, the final report, and the one-line diagrams. If the model is not released, a new engineer can still rebuild it from the report and field data.
How often does an arc flash study need to be updated?
NFPA 70E requires the arc flash risk assessment to be reviewed at least every five years and updated after major modifications or renovations. Changes in utility fault current or protective device settings are also good reasons to review it sooner.
Will a new firm need to visit my facility?
Yes. Even with good records, an engineer needs to verify that the installed equipment matches the model. The amount of field time depends on how complete and current your existing data is.
What should I do with the old labels during the update?
Keep existing labels in place until new ones are ready. If you know the system has changed since the labels were printed, talk with your engineer about interim precautions so workers are not relying on outdated values.
Who should stand behind an updated arc flash study?
A qualified engineer should lead the study and stand behind the results. Bowtie Engineering’s arc flash studies are led by licensed Professional Engineers, which gives your team and your insurer confidence in the numbers on every label.
Need help now? Call Bowtie Engineering at 866-730-6620 or request a quote online.
Key Takeaways
- Any qualified engineering firm can update an arc flash study another company completed, after verifying the data in the field.
- Hand over the report, model file, one-line diagrams, device settings, and a list of changes to speed up the update.
- NFPA 70E requires a review at least every five years and an update after major modifications.
- New labels may show different values because of system changes or the 2018 IEEE 1584 calculation method.
- Bowtie Engineering works in SKM, EasyPower, and ETAP and delivers labels, one-lines, and a full engineering report.
Contact Bowtie Engineering to review your existing arc flash study.