Yes — active arc-quenching systems (optical/light detection + crowbar/current-limiting methods) typically reduce incident energy far more quickly and reliably than RELT/ERMS maintenance switching, and they do so without depending on an operator to enable a special mode. That combination produces substantially lower incident energy, better protection of equipment, improved uptime, and stronger liability defensibility for owners and engineers.
Why millisecond performance matters
Incident energy scales directly with arc duration; shorten the event and the energy falls dramatically. IEEE 1584 and utility testing have long shown that reductions in clearing time translate to proportionate drops in cal/cm² exposure. Active arc-quenching systems detect and act in the single- to low-millisecond range (often <4–8 ms total extinguishing time), whereas breaker mechanical clearing or ERMS/RELT-based clearing is typically tens of milliseconds and depends on breaker trip actuation and mechanical timing. The result: arc-quenching can reduce incident energy from tens of cal/cm² to single-digit or sub-1 cal/cm² levels in many cases.
Human error: the single biggest shortcoming of maintenance switches
Energy-reducing maintenance switching (RELT/ERMS) requires an operator to enable maintenance mode before work. Missing that step — ambiguous labeling, procedure lapses, shift changeovers, or contractor unfamiliarity — negates the protection. Active arc-quenching is “always on”: it senses an internal arc and immediately redirects or limits energy automatically, removing the operator dependency that causes many real-world incidents.
Coordination and uptime — no tradeoffs
RELT/ERMS often sacrifices selective coordination while enabled because instantaneous thresholds are reduced, which can allow downstream devices to trip out of sequence during maintenance. In contrast, arc-quenching interventions extinguish the arc locally (for example via a low-impedance path or rapid earthing action) and permit normal protection coordination to remain unchanged for routine faults and upstream protection. That preserves uptime for critical facilities (data centers, manufacturing, utilities) while delivering superior safety.
Equipment damage and downtime
Even brief arcs can vaporize copper, damage insulation, and cause structural blast damage. By extinguishing arcs before they fully develop, arc-quenching systems dramatically reduce physical damage and the long repair timelines associated with major arc-blast events. Owners frequently justify the additional capital cost with avoided repairs and lost production.
Quick comparison
| Feature | RELT / ERMS (maintenance switch) | Arc-Quenching (optical/crowbar / UFES / AQS) |
| Typical total clearing time | 30–50 ms (breaker dependent) | 1–8 ms (detect + extinguish). |
| Requires operator action | Yes — must enable maintenance mode | No — automatic, always active. |
| Effect on selectivity | Reduced when active | Maintains coordination for normal faults. |
| Equipment damage risk | Higher (longer arc duration) | Much lower (arc suppressed early). |
| Typical PPE impact | Reduced only when enabled | Can lower category across more scenarios. |
Practical takeaways for engineers and owners
- For systems where uptime, rotating/contract labor, or very high available fault current make procedural compliance brittle, arc-quenching is the stronger engineering control.
• NEC 2020 (240.87) recognizes several methods for arc-energy reduction; arc-quenching is an accepted active-mitigation technique that often achieves the lowest incident energy in practice.
• Where budgets allow, specifying arc-quenching on main switchgear or high-energy bus sections delivers both safety and business continuity benefits that typically outweigh the incremental cost.
At High Power Products we guide customers through evaluating arc-quenching versus traditional options and help specify systems that meet NEC requirements while optimizing for safety and uptime. Request a quote to discuss arc-quenching solutions tailored to your project: Contact Us.