Safety, Isolation & Stored Energy

Stored Electrical Energy / Arc Flash on De-energization

The breaker was off. Nobody tested it. It wasn't the only feed.

What happened

Electrical gear is switched off and everyone assumes it's dead. But "off" isn't proven until you test it — capacitors, drives, or a hidden second feed can still be holding lethal energy.

Why it matters

Touching "dead" gear that's actually live can trigger an arc flash — an electrical explosion hot enough to kill or cause life-changing burns instantly.

Control sequence

Identify and isolate ALL energy sources (including possible back-feeds).
Discharge/bleed stored energy (capacitors, VFD DC buses) and wait the required time.
Lock and tag every isolation point.
Test for absence of voltage with a proven meter — live-dead-live.
Treat any untested part as energized.

How often

Industry estimates: ~30,000 arc-flash incidents per year in the US, ~7,000 burn injuries, ~2,000 hospitalizations, ~400 fatalities per year (widely cited industry figures — Eaton/ESFI-compiled estimates, secondary). OSHA/BLS ground truth: 1,201 OSHA-recorded…

Consequences

Class-level: arc flash burns, blast injuries, and fatalities on gear that was "switched off" but never tested dead; OSHA and NFPA 70E both treat untested parts as energized because this failure mode kills (OSHA 4472 / NFPA 70E) .

Evidence gate: publish only after verification

OSHA 29 CFR 1910.333: circuits must be locked out AND verified de-energized by a qualified person with proper instruments; untested parts are treated as energized (OSHA,…cited
NFPA 70E: electrically safe work condition = de-energize, isolate, lock/tag, test for absence of voltage, address stored energy (capacitors, VFDs) (NFPA 70E via OSHA…cited

ExperienceLearn it, live it

Coming soon

EON Life Simulation

Walk into the accident and practise freely, no score. The physics decides, unscripted.