Arc flash study · Northern Virginia · NEC 2020 (2021 USBC) · NFPA 70E 2027
Northern Virginia has the largest data center fleet on earth, and the oldest arc flash labels.
674 data center facilities in Virginia, 140 of them in Ashburn, most studied during the 2019-2021 build wave. NFPA 70E caps a study at five years. Send your bus count and a VB engineer scopes the reassessment in two business days, free.
1,000+ assessments21 countriesSince 2014PE stamp on request
Free campus scoping
Bus count in, scope out. Tell us the bus count, the voltage classes and whether one-lines exist. A VB engineer replies in two business days with the scope, the timeline per block and the deliverable list. Short form, no phone number.
Scoping is free and carries no obligation. The scope is yours to put beside any other proposal.
Trusted on plants that cannot stop
- 0data center facilities in Virginia
- 0of them in Ashburn alone
- 0maximum age of a study under NFPA 70E 130.5(G)
- 0arc flash assessments delivered
- 0countries, one signed report
Facility counts: DataCenterMap, Virginia and Ashburn, read 1 October 2026. Assessment counts: VB Engineering project register.
How the free scoping works
- 1
Send the bus count
Buses by voltage class, the year of the last study, and whether one-lines and the old model exist. Three minutes.
- 2
An engineer scopes it
Reassessment or new study, per block. What is reused, what is re-walked, what is re-labeled, and in what order so no hall waits.
- 3
Scope and timeline in two days
Deliverable list, duration per block, basis of pricing per bus, and the professional engineer stamp option. In writing, yours to forward.
The duty
Does Virginia require an arc flash study?
No Virginia statute names an arc flash study. The duty arrives three ways: OSHA 29 CFR 1910.132(d) requires a written hazard assessment, enforced in Virginia through VOSH; NFPA 70E 2027 130.5 requires an arc flash risk assessment before energized work; and NEC 110.16, adopted as NEC 2020 under the 2021 Uniform Statewide Building Code, requires the label on the gear. One study satisfies all three.
| Instrument | Clause | What it requires | Who checks it |
|---|---|---|---|
| OSHA, via VOSH | 29 CFR 1910.132(d) | A written certification that the workplace hazard assessment was performed, dated and signed | VOSH compliance officer, after an incident or a complaint |
| OSHA, via VOSH | 29 CFR 1910.333 | Safe work practices on energized equipment; the study sets the boundaries those practices use | VOSH, the insurer's loss-control engineer |
| NFPA 70E 2027 | 130.5 · 130.5(G) | Arc flash risk assessment before energized work, reviewed at least every five years and after any system change | Your EHS lead, the insurer, FM Global on insured sites |
| NFPA 70E 2027 | 130.5(H) | Label content: nominal voltage, arc flash boundary, and incident energy or PPE category at the working distance | The electrician in front of the panel |
| NEC 2020, via 2021 USBC | 110.16 | Arc flash hazard warning label on switchboards, panelboards, MCCs and the like | The AHJ electrical inspector at the permit |
| NEC 2026 (not yet adopted in Virginia) | 110.16(B) | Adds the date of the arc flash risk assessment to the label | The inspector, once Virginia adopts; the insurer already asks |
Virginia is on the 2020 NEC, effective 18 January 2024. Georgia and Ohio are on NEC 2023. The gap matters less than it looks: the label content comes from NFPA 70E, and the five-year clock comes from NFPA 70E, and neither waits for the state code cycle.
The clock
Is an arc flash study from 2020 still valid in Virginia?
Only until its fifth anniversary. NFPA 70E 2027 130.5(G) caps an arc flash risk assessment at five years and resets the clock whenever the electrical system changes. Northern Virginia added more data center capacity between 2019 and 2021 than any market in the world, and the studies done to energize those halls reach the limit in 2025 and 2026. A hall that has since added feeders, a UPS module or a battery cabinet reset the clock earlier.
Dated 2020 or 2021
At or past the five-year limit now. The labels on the gear say nothing about it, which is why NEC 2026 puts the date on the label.
The campus grew
A new hall, a feeder from a second substation, a generator paralleling change, a 2N UPS upgrade or a battery cabinet swap. Any one changes the fault current and the clock restarts.
The study cannot be found
Labels installed, report lost with the contractor, no model, no field data pack. That is not a reassessment candidate; it is a new study with a shorter walkdown.
What a dated label looks like
Every figure on a VB label traces to one row of the incident energy table: incident energy at the working distance, arc flash boundary, shock hazard voltage, the approach boundaries, the equipment name and the assessment date. The date is what the inspector, the insurer and your own electricians read first. A label without it answers none of their questions.
The scope
What does a campus reassessment cover?
A VB reassessment covers every bus from the utility service entrance to the last PDU and the battery cabinet, AC and DC in one incident energy table. The walkdown verifies the one-line and every protective device setting against the as-found plant, the model is re-run for every operating scenario including generator and UPS bypass, and the labels that changed are replaced with dated artwork. The output is a signed report an insurer, an inspector and an electrician can each open at their own page.
| In scope | Out of scope unless asked |
|---|---|
| Walkdown of every cubicle, nameplates, CT and PT ratios, trip settings photographed | Thermography and partial-discharge surveys (VB offers both as separate lines) |
| One-line reconciled to the as-found plant, drift logged, co-signed by the site engineer | Redrawing the as-built drawing set beyond the one-line |
| Short-circuit, protective device coordination and incident energy per IEEE 1584-2018, every operating scenario named | Relay setting changes implemented in the field (recommended in the action register, executed by your contractor or VB on request) |
| DC buses: UPS strings, battery cabinets, 48 V and 800 VDC distribution, method named per row | Battery capacity and runtime studies |
| Label schedule, dated artwork, installation by a VB crew, photographed installed | Signage beyond arc flash and shock labels |
| Action register with owners and dates; written hazard assessment certification per 1910.132(d); engineer of record signature; PE stamp on request | Qualified-person training (available through VB's training practice and Drona VR) |
Method and durations
- Walkdown · about one crew day per 10 MW block, every cubicle opened, read and photographed
- Model and calculation · ETAP or SKM PowerTools, two to three weeks for a multi-block campus, every scenario run
- Report · 11 sections per IEEE 1584.1-2022, signed by the engineer who ran it, PE review and stamp on request
- Labels · about 150 per crew day, dated artwork, installed and photographed
- Phasing · block by block, so no hall is held for another and the campus is never without current labels
A worked campus
What does a reassessment find on a campus studied in 2020?
On a modeled hyperscale campus in the US mid-Atlantic, five blocks and 87 buses first studied in 2020 and expanded twice since, a reassessment re-rates roughly one bus in three. The modeled result: 29 of 87 buses change PPE category, 11 of them upward because a second utility feed raised available fault current, and 6 buses in the new battery hall had never been studied at all. Every label on those 35 buses is replaced with dated artwork.
| Block | Buses | Changed category | Up | Down | Never studied | Labels replaced |
|---|---|---|---|---|---|---|
| Utility and MV switchgear | 12 | 7 | 7 | 0 | 0 | 7 |
| Hall A (2020) | 22 | 6 | 2 | 4 | 0 | 6 |
| Hall B (2020) | 22 | 5 | 1 | 4 | 0 | 5 |
| Hall C (2023 expansion) | 21 | 8 | 1 | 7 | 0 | 8 |
| Battery hall (2024) | 10 | 3 | 0 | 3 | 6 | 9 |
| Campus | 87 | 29 | 11 | 18 | 6 | 35 |
The buses that go down a category matter as much as the ones that go up: they are the buses where the crew has been dressing for a hazard that is no longer there, which is the cost of an old study that nobody counts. The buses never studied are the finding an insurer writes up.
Why the scope carries weight
Written by the team that has labeled 12,547 assets
Data centers, pharma, power, oil and gas and process plants in 21 countries. The engineer who scopes your campus has walked down campuses of this shape before.
IEEE 1584-2018 for the method, IEEE 1584.1-2022 for the deliverable, NFPA 70E 2027 and NEC 110.16 for the duty. ETAP and SKM PowerTools.
The engineer who ran the study puts their name on every section. A US-licensed professional engineer reviews and stamps the study on request.
UPS strings, battery cabinets and 800 VDC distribution sit outside IEEE 1584's AC range. VB studies them in the same table with the method named.
Block by block, with the testing contractor's outage windows. No hall waits for another and no hall is left without current labels.
No call unless you ask for one. The scope is in writing and yours to forward, whoever does the work.
Who brings the study
Three ways a reassessment reaches a Northern Virginia campus
The operator's facilities or EHS lead
Holds the 2020 report, knows the halls that were added since, and answers to the insurer's loss-control engineer. Scopes the campus directly.
The engineer of record or commissioning agent
Needs the coordination and arc flash results before witnessing energization of the next hall. VB delivers the block study on the Cx schedule.
The testing contractor
Already has the switchgear keys and the outage windows. VB runs the study behind the contractor's maintenance program and the contractor keeps the relationship.
VB also serves US data center campuses nationally and holds state pages for New Jersey, New York and Pennsylvania. Virginia work is delivered from VB's US office in Katy, Texas.
Before you ask
Questions before you request the scope
Does Virginia require an arc flash study?
No Virginia statute names an arc flash study, but the duty arrives three ways. OSHA 29 CFR 1910.132(d) requires a written hazard assessment, enforced in Virginia through the state plan, VOSH. NFPA 70E 130.5 requires an arc flash risk assessment before energized work. NEC 110.16, adopted through the 2021 Uniform Statewide Building Code as NEC 2020, requires the arc flash label on the gear. The study is the only document that satisfies all three.
Which NEC edition does Virginia enforce?
Virginia enforces the 2020 National Electrical Code under the 2021 Uniform Statewide Building Code, effective 18 January 2024. That is the oldest code edition among the three largest US data center states, and it predates the NEC 2026 110.16(B) rule that puts the study date on the label. The label content on a VB study follows NFPA 70E 2027 and NEC 2026 regardless of the state edition, so it does not age out when Virginia adopts a newer code.
Is an arc flash study from 2020 still valid in Virginia?
Only until its fifth anniversary. NFPA 70E 2027 130.5(G) caps an arc flash risk assessment at five years and resets the clock whenever the electrical system changes. A study completed in 2020 is at the limit in 2025, one from 2021 in 2026. On a Northern Virginia campus that has added halls, feeders or battery cabinets since, the clock reset earlier than that.
Who does arc flash studies for Ashburn data centers?
VB Engineering scopes and delivers arc flash studies and five-year reassessments for Ashburn, Sterling, Manassas and the wider Northern Virginia corridor from its US office in Katy, Texas, with 1,000+ assessments since 2014 across data centers, pharma, power and process plants in 21 countries. The engineer who ran the study signs it, and a US-licensed professional engineer reviews and stamps it on request.
Will Virginia data centers need new labels when NEC 2026 is adopted?
NEC 2026 110.16(B) adds the date of the arc flash risk assessment to the label, so a label without a date is visibly out of step with the current code whenever Virginia adopts it. The label content is set by NFPA 70E 130.5(H) and the NEC; the adoption timing is the state's. A VB label already carries the assessment date, so it is compliant under NEC 2020 today and under NEC 2026 when it arrives.
Does a five-year reassessment mean a full new study?
Not always. Where the one-line, the sources and the protective device settings are verified unchanged on a walkdown, the existing model is updated, re-run and re-certified, and only the labels that changed are replaced. Where the system has changed, or the original study has no model, no field data pack or no named engineer, the reassessment is a new study. The free scoping tells you which, before any money is spent.
How long does a reassessment take on a data center campus?
A VB reassessment runs in four stages: a walkdown of every cubicle at roughly one day per 10 MW block, modeling and short-circuit, coordination and incident energy calculation in ETAP or SKM PowerTools over two to three weeks, a signed report, and label installation at about 150 labels per crew day. A single-building campus is typically four to six weeks from walkdown to installed labels; a multi-block campus is phased per block so no hall waits for another.
What does an arc flash study cost in Virginia?
It is priced per bus, by voltage class, with the walkdown and label installation as separate lines, so two campuses with the same floor area can differ by a factor of three. VB does not publish a square-foot rate because the bus count is what drives the work. Send the bus count and the voltage classes through the scoping form and the scope, timeline and basis of pricing come back in two business days, free.
Does the study cover UPS strings, battery cabinets and 800 VDC distribution?
Yes, AC and DC in one scope and one incident energy table. IEEE 1584-2018 is validated for AC from 208 V to 15 kV, so DC buses are calculated by the DC methods NFPA 70E recognizes, with the method named on each row. A reassessment that leaves the battery room and the UPS output out of the table is not a reassessment of the campus.
What happens after I submit the scoping form?
A VB practice engineer reads the bus count, voltage classes and one-line status you entered and replies within two business days with the scope, the timeline per block, the deliverable list (report sections, label schedule, action register, certification) and the professional engineer stamp option. No call unless you ask for one. The scope is yours to put beside any other proposal.
Find out whether your 2020 study still stands before the insurer asks.
Send the bus count now. Scope, timeline per block and the professional engineer stamp option in your inbox within two business days. Free, in writing, yours to forward.
Scope my campusPrefer email? Send the bus count to connect@groupvb.com with "Virginia" in the subject line.