Cable gland requirement for intrinsically safe equipment Ex ia for IIC

[Jaivishnu]

Hi I am a mechanical engineer and so my electrical-related queries may appear to be totally dumb. My first doubt is: since intrinsically safe equipment is designed to produce very low energy such that ignition of the flammable mixture is avoided, is there any particular requirement that the cable entry points to the equipment are to be through a metal cable gland with a suitable cable diameter? Is a loose-fitting cable gland also acceptable since anyways flammable mixture is not going to be ignited at all.

My second doubt is: are there any standard guidelines that tells what type of cable gland are to be used for intrinsically safe devices in hydrogen (IIC) piping. Thanks

 

[FacEngrPE]

Is the code of construction NFPA 70 (National Electric Code), IEC, or something else?

Is a loose-fitting cable gland also acceptable since anyways flammable mixture is not going to be ignited at all.

If your equipment is filled with H2 and no oxidizer, and you have openings to ambient anywhere, the gas will form an explosive mixture near those holes. Not something I would do.

 

[srini1785]

IS barriers have a EXia rated terminal on one side and normal terminals on the other. The barrier itself is generally rated for Zone 2 installation only. So if your box is located in hazardous area then it necessitates that the Glands are compulsorily air tight.