Arc Flash Buddy

Version 3.1 · Vertiv field safety decision aid · 600 volts or less

Default scope: 600 V or less. This workflow is configured for Vertiv units supplied at 208 V, 230 V, or 460 V. The site study/label, employer electrical-safety program, current Vertiv manual, and applicable codes control. This app does not calculate incident energy or select PPE.

Step 1 of 5Identify the job

Step 1 · Start here

What are you working on?

Select the Vertiv unit voltage and why the electrical compartment will be opened. This workflow applies to 600 V or less.

Vertiv unit voltage

Reason for opening the electrical compartment

Step 2 · Choose the path

Will this task expose energized parts?

Answer for the work as it will actually be performed—not simply whether the unit is running.

No — make it electrically safeIdentify sources, isolate, LOTO, verify absence of voltage, then work.Yes — energized exposure requiredExamples: live measurement or justified diagnostics near exposed parts.

Step 3 · Normal operation

Is every condition satisfied?

Closed-door operation is normal operation only when all conditions are true.

Step 3 · De-energized path

Establish the safe-work condition

Complete the steps in field order. iCOM Off and a local disconnect alone are not electrical isolation.

1. Identify every source and possible backfeed
Remote feeder, local disconnect, condenser, reheat/humidifier, controls, transformer, UPS/control power, auxiliary feeds, induced voltage, and backfeed.2. Open remote/upstream disconnect(s)
The line side of a factory/internal disconnect may remain energized.3. Open applicable local disconnect(s)4. Apply lockout/tagout
Lock and tag each disconnecting means under the employer/site energy-control procedure.5. Try-start verification completed
Operate the normal controls to verify the unit cannot restart, then return controls to OFF/neutral.6. Verify absence of voltage — live/dead/live
Qualified person; properly rated meter; verify the tester on a known source before and after testing every relevant conductor and part.7. Control stored and non-electrical energy
DC bus/capacitors, fans, pressure, hot surfaces, water/steam, and automatic restart. Continue verification if energy can reaccumulate.

Manufacturer discharge time: Check the current unit, fan, and drive manuals for required stored-energy waiting periods. Begin the wait only after power is verified OFF; waiting does not replace LOTO or voltage verification.

Lock points / verification / special precautions

Step 3 · Energized path

Is energized diagnostic testing necessary?

Choose Yes only when the service or measurement cannot be completed de-energized. Choose No to route the job to LOTO.

Yes — energized diagnostics necessaryLoad shock and arc-flash requirements for 600 V or less.No — de-energizeRoute this job to the LOTO path.

Step 4 · Energized controls

Shock and arc-flash requirements

Qualified persons only. Defaults below apply to the 208 V, 230 V, and 460 V Vertiv selections. The equipment arc-flash label, site study, and employer program override these defaults.

Qualified for this electrical taskJob briefing completed, including emergency responseEquipment condition assessed; no unexpected abnormal condition

Limited approach boundary

Restricted approach boundary

Does the equipment have an arc-flash label showing incident energy in cal/cm²?

Yes — use the arc-flash labelEnter the incident energy, working distance, and boundary printed on the label.No — use the PPE-category methodUse only when the equipment, task, fault current, and clearing time are within the table limits.

Incident energy from arc-flash label

Working distance from label

Arc-flash boundary from label

PPE: Select arc-rated clothing and PPE with an arc rating at least equal to the incident energy shown on the label, following the employer program.

PPE category

Arc-flash boundary

Maximum available fault current

Maximum clearing time

I verified the actual task/equipment, fault current, and clearing time are within the applicable table limits

Shock PPE / insulated tools

Arc-rated clothing and PPE

If an arc-flash label shows incident energy, use that label and the site study. The PPE-category defaults are only usable when every applicable table condition and limit is satisfied.

Required field controls

Briefing and emergency readiness

Emergency response reviewed: equipment location, emergency disconnect, communication method, and response rolesMeter, leads, probes, insulating gloves/protectors, tools, and arc-rated PPE inspected before useArc-flash boundary controlled; unqualified persons kept outside required boundaries

Stop and reassess: Stop work and repeat the job briefing if the task, equipment condition, energy source, personnel, or work scope changes.

Step 5 · Job safety plan

Review before work

After work · Return to service

Re-energization sequence

Complete in order before restoring power, including temporary re-energization for testing.

Work complete; required tests and visual inspection performedTools, jumpers, shorts, grounds, and temporary devices removedGuards, covers, and electrical-compartment doors restored and securedAll employees visually confirmed clear; affected employees warnedEach lock and tag removed by the employee who applied it, under the site procedureUnit re-energized from a safe position and operation checked

Plan closed

Job plan completed

Submitted and closed.

Vertiv reference

Controller Off is not isolation

On iCOM-equipped units, Unit Off does not electrically isolate the equipment.

Local and remote disconnects

Open applicable local and remote supplies. The line side of an internal disconnect may remain energized.

Stored electrical energy

Fan controls, VFD/DC buses, and capacitors can retain charge after disconnection. Follow the current equipment and component manuals for required discharge times after verifying power OFF.

Safety limitation: Not an energized-work permit, LOTO procedure, arc-flash study, risk assessment, or substitute for NFPA 70E, OSHA, codes, schematics, manuals, or the employer/site program.