Battery rooms, UPS systems, DC auxiliary power supply panels in substations, and DC distribution systems have a different arc behavior than AC panels. Because the current in a DC arc does not pass through zero, the arc may not extinguish spontaneously; battery banks, on the other hand, remain energized on the source side even if the protection device trips.

Which DC equipment is being evaluated?

  • Battery banks and battery room distribution panels
  • Battery and DC bus sections of UPS systems.
  • Transformer substation and switchyard DC auxiliary power supply panels (110 V, 220 V DC)
  • DC distribution and DC microgrid systems
  • 24 V and 48 V DC control and communication panels

IEEE 1584 and DC

IEEE 1584-2018 defines incident energy calculation for three-phase AC systems at voltages between 208 V and 15 kV and frequencies of 50/60 Hz. Single-phase and DC systems are not included in the model; the standard only refers to methods in the literature (Ammerman, Das, Doan, Klement) for DC (clauses 4.11 and 4.12).

DC components (battery banks, DC side of inverters, PV arrays, DC distribution) are not calculated using IEEE 1584. In these components, incident energy is calculated separately using DC methods from the literature and reported separately from AC results; the methods and assumptions used are clearly stated in the report.

Do 24 V and 48 V DC panels need an arc flash study?

In very low-voltage DC control panels, the risk of arc flash is generally low. However, this decision depends on the panel's contents: if the panel has an AC input, battery bank, or a source capable of delivering high short-circuit current, that section is evaluated separately. Therefore, low-voltage DC panels are not labeled "out of scope" without on-site inspection.

Data requested in the DC study

  • Battery type, number of cells, capacity, and manufacturer's short-circuit current data.
  • UPS brand, model, and power information.
  • DC distribution single-line diagram
  • Types and values of DC protection elements (fuses, DC circuit breakers)
  • Cable cross-sections and lengths between the battery and the control panel.

For safety requirements of DC installations Safety in DC power distribution systems. And DC microgrid electrical safety You can browse our pages.

Reducing incident energy

The calculation results are used not only for selecting PPE but also for reducing risk at its source. The report provides panel-specific recommendations; commonly applied methods include:

  • Reconfiguring protection settings to take incident energy into account.
  • Fast-trip (maintenance mode) settings enabled during maintenance.
  • Arc detection relays (light and current sensing)
  • Remote switching and remote racking of withdrawable breakers.
  • DC protection element and battery compartment separation located near the battery bank.

De-energized work always comes first; energized work is permitted only when justified and under an energized electrical work permit.

The scope of AES Innovation

We conduct arc flash analysis end-to-end, including data collection, modeling, incident energy calculation, reporting, and labeling. Reports can be prepared in Turkish, English, or bilingually. For general process and pricing factors, please contact us. arc flash analysis and labeling You can check out our page.

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Frequently Asked Questions

Are the DC results the same as the AC report?

No. DC results, along with the methods and assumptions used, are reported in a separate section from AC results.

Does the danger end after the protective device in the battery room is activated?

No. The battery bank remains energized on the source side; the section between the battery and the first protection element is evaluated separately.

Are the AC and DC sides of a UPS calculated separately?

Yes. The AC input and output panels of a UPS are calculated according to IEEE 1584, while the battery and DC sections are calculated using DC methods.