Arc Flash

Arc flash is a hazard associated with working on live electrical power circuits.

Personal protective equipment should be worn when working on such circuits but even this cannot always protect against the danger of electrical explosions that could occur due to a short circuit fault.

Arc flash hazards are a well-documented problem and pose a real and significant risk.

Fuse links are ideal for reducing this hazard since most fuse links have extremely good current limiting properties.

An arc flash is caused by very high short circuit currents causing conductors or components within the circuit to explode.

A fuse can reduce the short circuit current to a much safer level and can, in some cases, eliminate the risk of an arc flash explosion altogether.

How do breakers manage their weaknesses ?

ACB case (air circuit breaker)

  • Drawouts


  • Arc Containment Enclosures


  • Maintenance Plans


  • Specific Accessories

MCCB & ACB manufacturers are aware of the problems:

  • Drawout: quickly replace the breaker as we would do with a fuse
  • Enclosure configuration: no arc contamination on surrounding products
  • Maintenance plan: replacement of internal parts (contacts, arc chamber, etc…) – althought this can becom very expensive
  • Specific accessories: expulsion of material makes the operation of drawout very risky (risk of internal arcing on drawable contacts).

Risks are directly related to the short circuit level. They are strongly reduced under 10kA.

Arc Flash Accident

Case Studies