Main IEC Protection Techniques

Main IEC Protection Techniques


Table 7. Main IEC Protection Techniques

Flameproof “d”

Flameproof "d"
  • Zone 1
  • Contain internal explosion
  • Control external temperature of enclosure
  • Similar to NEC® explosion proof

Increased Safety “e”

Increased Safety "e"
  • Zone 1
  • High impact resistant enclosures

– FRP, GRP, Sheet steel/Aluminum

  • Will not hold static charge
  • Use approved components
  • Control internal and external temperature
  • Maintain minimum of IP 54 ingress protection
  • No arcs, no sparks

Flameproof Plus Increased Safety “de”

 Flameproof Plus Increased Safety "de"
  • Zone 1
  • Location of arcing has “d” protection (flameproof)
  • Connection terminals have “e” protection (increased safety)
  • Typical use in switches, lighting, power outlets

– where arcs can normally occur


Non-Sparking “n”

Non-sparking "N"
  • Zone 2
  • Equipment has no normally arcing parts
  • Thermal effects incapable of ignition
  • nA = non sparking
  • nR = restricted breathing
  • nC = hermetically sealed non-incendive


Pressurized Apparatus “p”

Pressurized Appartus "p"
  • Zone 1
  • Expels ignitable vapor / gasv
  • Maintains positive enclosure pressure


Intrinsic Safety “ia” – “ib”

Intrinsic Safety "ia" - "ib"
  • ia Zone 0 & 1
  • ib Zone 1
  • Incapable of releasing enough energy to cause an explosion


Encapsulation “m”

  • Zone 1 category
  • Protection where parts that are capable of ignition by spark of heat are enclosed in a compound in such a way to prevent such ignition from occurring


The content in this section presents general information describing the classification systems that Guardian Telecom designs, manufactures and markets telephone and paging system products to, including ATEX, NEC, CEC and IEC.
All information is for general reference purposes only. All applicable local and national regulations and practices concerning Explosion Proof and Hazardous Area communications equipment must be strictly followed and adhered to.
For detailed information refer to published documents on hazardous location definitions and installation requirements presented by: 1) NEC®, 2) CEC Canadian Electrical Code, 3) IEC