Ex-pert Electrical Technologies

Dynamic elaboration on the Art & Science of Hazardous Area Protection

Powder-Filled ‘q’


This protection technique is governed by IEC 60079-5 

EPL associated with [ q ] = Gb or Mb

This standard applies to :-

  • Electrical Equipment
  • Parts of Electrical Equipment
  • Ex Components


  1. A rated supply current of less than or equal to 16 amps
  2. Rated supply voltage of less than or equal to 1000 Volts
  3. rated power consumption of less than or equal to 1000 Watts

Powder filling originated in France as a concept in 1954, but it was not generally recognized as an Ex Protection concept until the publication of IEC Standard 60079-5 in 1967. This protection method is typically used only for small transformers, capacitors and on electrical components that have no moving parts. The protection consists of a sealed enclosure (normally with a vent) containing quartz sand (the origin of the “q” description), powder or glass beads.

Electrical equipment and Ex components protected by powder filling “q” may contain :

  • electronic circuits
  • transformers
  • protection fuses
  • relays
  • intrinsically safe electrical apparatus,
  • associated electrical apparatus
The Technique/Construction 

Example : Electronic Ballast for Hazardous Area Fluorescent Fixture (Type Ex ed) Ex q-example

 Another Example , 100 Watts Power Supply in Aluminum Enclosure with non-metallic Ex e Cable Glands for external connections through cables.

(Protection : Ex eq)

Ex q Power Supply Example

The Filling Material

Filling material is  Solid quartz or Solid Glass Particles. Filled completely.

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