Industry · utilities and power generation
Utility arc flash study that covers the plant, the substation and the line crew
US arc flash studies, PE-reviewed, quoted in 24 hours. The right method for each voltage, not one method for all.
- PE-reviewed
- Built on current NFPA 70E-2027
- IEEE 1584-2018
- Field engineers travel to every US state
- Written quote in 24 hours
A utility arc flash study estimates the incident heat energy line and plant workers could face, from generator auxiliaries and station service to substations and distribution, and sets the arc-rated protection each task needs. OSHA 29 CFR 1910.269 requires that estimate for utility work. AFSC chooses the right calculation method for each voltage.
Why now
When utilities and generators commission the study
A new interconnection or repowering
New generation or a changed interconnection moves fault levels at the plant and the substation together.
An OSHA or internal safety review
Reviewers ask how incident heat energy was estimated for each task. A documented study answers that in one file.
Crews still use blanket PPE
One arc rating for every task is either too low for some work or needlessly heavy for the rest.
Hazards and governing standards for utility work
| Reference | Scope |
|---|---|
| OSHA 29 CFR 1910.269 | Generation, transmission and distribution work; requires an estimate of incident heat energy |
| NESC (ANSI C2) | Utility installations and arc-rated protection for utility workers |
| NFPA 70E-2027 | Non-utility electrical work at the site, such as offices and shops |
| IEEE 1584-2018 | Incident energy for three-phase AC from 208 V to 15 kV |
Typical scope at a plant or substation
| Area | What we model and label |
|---|---|
| Generator and auxiliaries | Station service switchgear and MCCs at 4.16 kV and 480 V |
| Plant substation | Step-up transformers and medium voltage switchgear |
| Distribution substations | Breakers, reclosers and relay settings, with clearing times from your relay data |
| Above 15 kV | Methods suited to higher voltages, as referenced in OSHA 29 CFR 1910.269 Appendix E |
| Battery and DC systems | Station batteries assessed with DC methods |
Outage plans close early. Get on the list.
Send the station one-line and your outage calendar. A fixed price and a field plan aligned with your system operator come back within one business day.
What a typical project looks like
Illustrative scenario, no client named and no figures claimed: a generating station updates its study ahead of a planned unit outage. Engineers collect auxiliary system data while the unit runs, coordinate substation relay data with the protection group, and install labels on station service gear during the outage window, ready for restart.
Power plant arc flash study, from auxiliaries to the switchyard
A power plant arc flash study covers two worlds. Station service gear inside the plant behaves like an industrial system and is modeled to IEEE 1584-2018. The switchyard and generator step-up equipment run at higher voltages, where other methods apply. We model both, and report each result with the method behind it.
Substation arc flash study and a worked example
A substation arc flash study estimates incident heat energy at breakers, switches and bus work where line crews operate and maintain equipment. Relay settings and breaker clearing times drive the result. A substation arc flash study example in our sample report shows the format: each location, its voltage, clearing time, estimated energy and the arc rating required.
Frequently asked questions
Question not here? Ask an engineer
Does NFPA 70E apply to utilities?
Not to utility generation, transmission and distribution installations; those fall under OSHA 29 CFR 1910.269 and the NESC. NFPA 70E-2027 still applies to non-utility electrical work at the same sites, such as offices, warehouses and shops. A good utility study states which rule governs each location.
What does OSHA 1910.269 require for arc flash?
It requires employers to assess workplaces for flame and arc hazards, make a reasonable estimate of the incident heat energy each exposed employee could face, and provide arc-rated protection at least equal to that estimate where it exceeds 2.0 cal/cm². The study is how that estimate is documented.
Which method do you use above 15 kV?
IEEE 1584-2018 stops at 15 kV, so higher voltages use other recognized methods, such as those listed in OSHA 29 CFR 1910.269 Appendix E. We choose the method that fits each location, state it in the report, and keep the PE review consistent across every voltage level.
Can you work with our protection group?
Yes. Relay settings drive clearing times, and clearing times drive incident energy, so we work from your protection group's settings files and return any setting change that would cut the hazard. Changes stay their decision; we model the effect so they can weigh it.
Do generator modes change the results?
Yes. Fault current differs when units are online, offline or islanded, and so does incident energy at the auxiliary buses. We model the operating modes that matter at your plant and label each location with the worst case, so the protection holds whatever the dispatch.
How fast can we get a price?
Within 24 hours. Send the station one-line, a list of substations in scope and your outage calendar, and an engineer returns a fixed written price with a dated plan aligned to your planned outages. No site visit is required to receive the quote.
Get your arc flash study quoted
Tell us about your facility. An engineer replies within one business day with scope, timeline and price.
- IEEE 1584-2018 and NFPA 70E-2027, PE-reviewed
- Labels and training in the same scope
- Field engineers travel to any US state