Arc Flash Study Explained: When Required, What It Produces

Last Updated: 2026-10-30

Answer Capsule: An arc flash study is the engineering analysis behind the arc flash risk assessment that NFPA 70E-2024 Section 130.5 requires before employees work on energized equipment. It models fault current and protective device clearing times per IEEE 1584-2018 and produces incident energy, arc flash boundaries and the label data NEC 2026 Section 110.16 requires on each piece of equipment.

The inspector asks for the arc flash study behind your labels, and you hand him the labels. He hands them back. A label without a study is a guess with an adhesive backing, and inspectors, safety officers and OSHA compliance officers all know it. If you bid commercial work or own a facility, someone will ask for the study.

This guide explains what an arc flash study is, when it is required, what a good one produces, who can perform it, and what drives the cost. You will also see how the study turns into the labels on your gear, which is the part Print Pro AZ handles every week. Brent Hanke has reviewed study tables from engineers across the country, and the same gaps show up over and over.

What Is an Arc Flash Study?

An arc flash study is the engineering analysis that calculates how much heat energy a worker would receive if an arc fault happened at a given piece of equipment. Engineers also call it an arc flash hazard analysis or incident energy analysis. It answers three questions for every bus and panel: how much energy, at what working distance, and how far away does that energy fall below 1.2 cal/cm2.

The study is not the same thing as the arc flash risk assessment, although people use the terms together. NFPA 70E-2024 Section 130.5 requires the risk assessment, which identifies the hazard, estimates the likelihood and severity of injury for the task, and decides what protective measures to use. The study supplies the numbers that make the assessment possible. Without it, the "severity" step is a guess.

What that means for you: the study is a document, usually a stamped report plus a data table, and it belongs to the facility owner. Your labels are printed from it. If you cannot find the report, you cannot defend the labels.

When Is an Arc Flash Study Required?

An arc flash study is required whenever employees will work on or near energized equipment that must carry an arc flash label, which under NEC 2026 and NFPA 70E-2024 covers nearly every non-dwelling facility. Three documents drive the requirement.

Document	What it requires	When it triggers a study
NFPA 70E-2024, Section 130.5	An arc flash risk assessment before work where an arc flash hazard exists, and a label with the data under 130.5(H)	Before energized work on any equipment likely to need examination, adjustment, servicing or maintenance while energized
NEC 2026, Section 110.16	A data label showing nominal voltage, arc flash boundary, incident energy or PPE category, and the assessment date on non-dwelling service and feeder equipment	At installation or inspection, at any amp rating, once your state or city adopts the 2026 edition
OSHA 29 CFR 1910.132(d) and the General Duty Clause	A PPE hazard assessment and protection from recognized hazards	Any workplace where employees are exposed to the arc flash hazard

The 2026 NEC change is the one that catches contractors. Earlier editions set an amperage threshold: 1200 A in 2020, then 1000 A in 2023. The 2026 edition removed the threshold, so any service or feeder supplied switchboard, switchgear, panelboard, industrial control panel, MCC or meter socket enclosure in a non-dwelling occupancy needs the full data label. A generic "ARC FLASH HAZARD" sticker no longer satisfies 110.16 under 2026.

Callout: adoption varies by state, and Arizona jurisdictions adopt on their own schedules. Confirm which NEC edition your AHJ enforces before you assume the threshold is gone. NFPA 70E does not wait for adoption, so the workplace requirement applies now.

Can You Use the PPE Category Tables Instead of a Study?

You can use the arc flash PPE category method under NFPA 70E-2024 Section 130.5(G) instead of a full incident energy analysis, but it is a lighter study, not no study. Table 130.7(C)(15)(a) covers AC equipment and 130.7(C)(15)(b) covers DC. Each table entry lists a maximum available fault current and a maximum clearing time, and you must prove your equipment falls under both limits before the table applies.

The table method is disqualified when any of these is true:

• Available fault current is above the table limit.
• The overcurrent device clearing time is above the table limit.
• The equipment type is not listed in the table.
• The equipment is not properly installed and maintained.

Proving the first two still takes a short-circuit calculation and a look at the device curves. That is why most engineers steer owners toward the full incident energy method. Whichever method you choose, use one per piece of equipment; a label showing both fails inspection.

What Are the Steps in an Arc Flash Study?

An arc flash study follows a fixed sequence, because each step feeds the next and a mistake early on shows up on every label. Here is what a complete study looks like from kickoff to labels:

1. Field data collection. The engineer or a technician walks the site and records every transformer, panel, breaker, fuse, relay setting, conductor size and length.
2. One-line diagram. The collected data becomes an accurate one-line of the distribution system. Old drawings are a starting point, never a substitute.
3. Utility data. The engineer requests available fault current and the upstream device data from the utility.
4. Short-circuit study. The model calculates bolted fault current at every bus.
5. Protective device coordination study. The engineer plots time-current curves and determines how long each device takes to clear a fault at that bus.
6. Incident energy and boundary calculation. Using IEEE 1584-2018, the model applies electrode configuration, enclosure size correction and the 2 second maximum clearing time convention to produce incident energy at the working distance and the arc flash boundary.
7. Label data table and report. The results become a table with one row per piece of equipment, plus a written report that documents the method and the data, as 130.5(H) requires.
8. Labels, PPE and training. The owner prints and installs the labels, updates PPE, and folds the results into the electrical safety program and the training under 110.6.

Print Pro AZ enters the process at step 8. Everything before that is engineering, and it belongs with a licensed engineer.

What Does an Arc Flash Study Produce?

A finished arc flash study produces five deliverables: a one-line diagram, a short-circuit study, a protective device coordination study, an incident energy table and the arc flash label data. Ask for all five by name when you request a proposal.

Deliverable	What it is	Who uses it
One-line diagram	A verified drawing of the power system from utility to loads, with equipment IDs that match the labels	Electricians, engineers, the AHJ
Short-circuit study	Available fault current at every bus, compared with equipment interrupting ratings	Engineers, the AHJ, insurers
Protective device coordination study	Time-current curves and recommended settings so the nearest device clears first	Electricians setting breakers and relays
Incident energy table	One row per bus: voltage, fault current, clearing time, working distance, incident energy, arc flash boundary	Safety managers, PPE selection, the label printer
Arc flash label data	The exact text for each label, including the method chosen and the assessment date	Print Pro AZ, the installer, the inspector

Two more items belong in the report. The first is documentation of the calculation method and the data behind it, because NFPA 70E 130.5(H) requires that to exist and to be reviewed. The second is a recommendations section, where good engineers flag buses with high incident energy and suggest fixes such as maintenance switches, faster settings or arc-resistant gear. That section is where the study pays for itself.

The full list of what belongs on each label is in the Print Pro AZ NFPA 70E 2024 arc flash label requirements guide.

How Much Does an Arc Flash Study Cost?

The cost of an arc flash study depends mainly on the number of protective devices and buses the engineer has to model, so no honest proposal quotes a flat price before a device count. Print Pro AZ does not sell studies or publish dollar figures, but every proposal we see is built on the factors below:

• Device and bus count. Every breaker, fuse and relay is a data point to collect, model and coordinate. This is the biggest driver.
• Quality of existing drawings. A current one-line cuts the field survey. No drawings means the engineer rebuilds the system from scratch.
• Site access. Equipment that needs a shutdown or an escort to open costs more to survey than gear in an unlocked electrical room.
• Voltage levels. Medium voltage gear and utility-owned equipment add relay work and utility coordination.
• Number of sites. Multi-site portfolios often price per site with a shared model.
• Deliverable scope. A short-circuit and coordination study alone costs less than the full package with labels and training.

How to lower the number: gather your drawings, settings and utility bills before the engineer arrives, and give them a single escorted visit. The device count does not change, but the hours do.

Who Can Perform an Arc Flash Study?

An arc flash study should be performed by an electrical engineer experienced in power systems, and most owners require a licensed professional engineer to stamp the report. NFPA 70E does not name a credential. It requires that the method and data be documented and defensible, and in practice that means an engineer running the IEEE 1584-2018 model in power systems software.

A few people who should not perform the study: the label vendor, the PPE vendor and a software trial run by someone who has never built a one-line. Print Pro AZ prints what the engineer produces. Brent Hanke's rule is that if a study arrives without a one-line and a named engineer, it goes back before a single label is printed.

How Often Must an Arc Flash Study Be Updated?

NFPA 70E-2024 Section 130.5(H) requires the data behind the labels to be reviewed at intervals not exceeding 5 years, and updated whenever a change in the electrical distribution system could affect the results. The 5-year clock is the outside limit. The change triggers are what usually get missed:

• A protective device, fuse or trip setting changes.
• A new utility source, generator, battery system or tie is added.
• A transformer kVA, impedance or configuration changes.

One more trigger applies to older studies. IEEE 1584-2018 replaced the 2002 model, added electrode configuration and enclosure size correction, and removed the old exemption for systems below 240 V fed by a single transformer under 125 kVA. Any study still built on 1584-2002 should be re-run, and the labels replaced with the new assessment date.

How Do You Turn the Study Into Labels?

You turn an arc flash study into labels by exporting the incident energy table, checking it for the errors that fail inspections, and sending it to a printer who reproduces the values exactly. Print Pro AZ takes the table as a PDF, Excel or CSV and produces the label set on UV-rated polyester or .048 aluminum, with same-week shipping.

Check the table for these four items before you send it:

1. One method per row. Incident energy with working distance, or PPE category, never both on the same equipment.
2. The assessment date. NEC 110.16 wants the date the assessment was completed, not the date the label is applied.
3. Equipment IDs that match the one-line. "MSB-1" on the label must be "MSB-1" on the drawing and on the gear.
4. Complete boundaries. Every row needs an arc flash boundary, even where incident energy is below 1.2 cal/cm2.

Here is a call Print Pro AZ gets every month: a facility manager forwards an engineer's spreadsheet and asks for labels by Friday. The sheet shows "CAT 2" in one column and "8.7 cal/cm2" in the next for the same bus, and the date column holds the date the manager opened the file. Brent Hanke sends it back with both issues marked. The engineer picks the incident energy method, fills in the real completion date of 08/12/2026, and the corrected set ships the same week.

For the step-by-step file prep, read how to order arc flash labels from your engineering data, then browse the arc flash label collection for formats and materials.

Frequently Asked Questions

What is the difference between an arc flash study and an arc flash risk assessment?

The arc flash risk assessment is the process NFPA 70E-2024 Section 130.5 requires: identify the hazard, estimate likelihood and severity, and choose protective measures. The arc flash study is the engineering calculation that supplies the incident energy and boundary numbers used in that assessment. You need the study to do the assessment properly.

Is an arc flash study required by OSHA?

Not by name. OSHA requires a PPE hazard assessment under 29 CFR 1910.132(d) and protection from recognized hazards under the General Duty Clause, and its 2006 letter of interpretation calls NFPA 70E a widely accepted approach. An arc flash study is how employers show they assessed the hazard the way NFPA 70E describes.

Do I need a new arc flash study if I change a breaker?

Often, yes. NFPA 70E 130.5(H) requires an update when a change in the distribution system could affect the results, and a protective device, fuse or trip-setting change is exactly that. Ask the engineer to re-run the affected buses and issue new label data with a new assessment date.

Can I do an arc flash study myself?

Not in a way that will hold up. The study requires a verified one-line, utility fault data, a short-circuit model, device coordination and the IEEE 1584-2018 calculation. That is licensed engineering work. Print Pro AZ prints the results and will not print labels from numbers that do not trace back to an engineer.

Conclusion

An arc flash study is the engineering work behind every legitimate arc flash label. NFPA 70E-2024 Section 130.5 requires the risk assessment it supports, NEC 2026 Section 110.16 requires the data it produces at any amp rating, and IEEE 1584-2018 is the model that produces it. Cost follows device count, the deliverables are the one-line, short-circuit study, coordination study, incident energy table and label data, and the whole package must be reviewed at least every 5 years.

Getting the study and the labels right the first time saves you inspection delays and re-trips. Have a commercial job with a study in hand? Send us your plan sets and Print Pro AZ will turn the table into a label set, or call Brent at (602) 649-5305.

Sources

• NFPA 70E, Standard for Electrical Safety in the Workplace: https://www.nfpa.org/codes-and-standards/nfpa-70e-standard-development/70e
• IEEE 1584-2018, Guide for Performing Arc-Flash Hazard Calculations: https://standards.ieee.org/ieee/1584/5522/
• OSHA 29 CFR 1910.132, Personal protective equipment, general requirements: https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.132

Brent Hanke | Print Pro AZ | (602) 649-5305 | b.hanke@printproaz.com

Brent Hanke is the founder of Print Pro AZ, supplying NEC-compliant labels to contractors across the country.