Cable Gland

Rather depends where it's going to be used.

Yes.

For procurement of cable glands - hazardous area classification is important and equally important are providing the vendor the physical dimensions of the cable i.e overall dia, under armour dia, and armour type and sixe flat or wire etc.. as if you go through the certification of glands and conduits for explosion proof area - you will note that if the gland size and fitting are such that gaseous material can travel in / out the gland is not considereed to be explosion proof. So proper rubber washer - the sealing element has to be designed there in the gland. Thisis a small item of the system but it is extremely important in the scheme else some explosion inside the junction box may case fatality in the plant.

Moreover there is significant difference in design of gland for general purpose and flame proof cases.. in later case the threads are tapered and do not have a check nut as it is expected to tighten the gland to the extant it can so that any possibility of gas traverse is done away with.

Yes of course, just like you need to specify whether is is an Ex(e) or Ex(d)/ Ex(i) gland, which will depend on the area classification in which you wish to install the JB.

Note the certification of the junction box itself, and take your lead from that.

eg If it states the temperature rating on the data plate, then match your gland to that.

Not if the junction box is Ex e.

Not if all of the circuits passing through the junction box are Ex i.

True, but in the face of the OP's query, one cannot explain from first principles here.....for that there are text books and training courses available.

The OP might as well have asked the JB supplier for instant advice. Bear in mind he stated that he needed to 'specify'; that this is an engineering forum (he will probably act on advice); that the JB certification is unstated, and that no area classification was given I am uncertain that he even understands "area classification". Also, no country of origin given, so 'Jose' is the only clue (USA, S.America; Europe ? ie different codes)

please will you explain more why not?

thanks

An (IEC) Ex e junction box does not contain devices producing arcs, sparks or other sources of ignition.

An Ex i circuit is isolated such that the circuit does not carry sufficient energy to produce a source of ignition.

...therefore cable glanding does not need to perform as it would were the installation Ex d - with Ex d the clearances between mating parts of the enclosure, including the gland, have to be sufficiently type-tested so as to give a high level of confidence in being able withstand an explosion inside the enclosure for real without igniting the atmosphere outside. Such a requirement simply does not exist in Ex e and Ex i; one could use bare conductors in the hazardous area under Ex ia _{though quite why one would want to is open to debate ad nauseam}, so of what use is a hazardous area cable gland in such circumstances (rhetorical question - NNTR)?

In continuation, I would like to emphasis that cable glands themselves are not explosion proof or otherwise classified for hazardous areas. They become explosion proof or suitable for any other level of hazardous area, when fixed to a JB/ starter etc units. Therefore the gland needs to be considered as integral part of the system so ... requirement specific details must be provided to gland vendor.Kindly once go through the certification provided for your required classification of Hazardous for the glands to be more clear of the subject. With these information even material of the gland is decided.