Battery knowledge · High-voltage and functional safety
Arc flash
The burst of heat, light and pressure released by a fault arc. The hazard to a worker is rated as incident energy at working distance; 1.2 cal/cm² is the usual onset of second-degree burns. Large battery systems can feed fault currents of many kiloamperes, so arc flash sets protective clothing and approach limits under NFPA 70E.
- Also called
- DC arc flash, arc-flash hazard, incident energy
- Unit
- cal/cm²
Example
High-voltage and functional safety: an example situation
Normal-operation current limits do not demonstrate correct contactor behavior under a welded-contact or sensor fault.
Read Arc flash alongside Arcing in this context. Current continuing through ionised gas across a gap, typically between contacts as they separate. An AC arc goes out by itself at each current zero, a hundred times a second at 50 Hz; a DC arc has no zero and keeps burning until it is stretched and cooled so far that its voltage exceeds the source’s, which makes high-voltage DC far harder to interrupt.
Use in Lemonergy
Relate protection to faults, detection and response.
This is a reference concept. No executable Lemonergy block has been verified for this term.
References & further reading
Further reading on this topic
These sources provide broader context; they are not presented as citations for every statement in this entry.
- ISO 26262-1:2018 — Road vehicles — Functional safety — Part 1: Vocabulary
International Organization for Standardization · 2018
Topic background · Scope and terminology of automotive electrical/electronic functional safety. The catalogue is not the full standard.