If you specify cable entries for flameproof equipment, the rulebook changed under you. IEC 60079-14 moved to Edition 6 in 2024, and the part that decides which cable entry device you are allowed to use into an Ex d enclosure was rewritten rather than tidied up. The old habit of picking a certified Ex db gland that fits the cable diameter, and treating a barrier gland as an optional extra for difficult cases, no longer survives the new selection logic.
The change matters most to the people furthest from the site: design engineers, EPC specifying teams and panel builders who issue the cable schedule long before anyone opens a gland box. Edition 6 pushes this decision upstream to them. This guide explains what the standard now asks you to prove, where a barrier gland became mandatory rather than advisable, and how to read the rule on a real project without guessing.
Key points
- Edition 6 assesses the cable and the cable entry device together as a system, instead of selecting the gland on its own.
- A flameproof barrier entry device is mandatory wherever the minimum external cable length cannot be met: 3 m for IIC and for IIB plus hydrogen, 0.5 m for IIA and IIB.
- Enclosure volume still matters. Above 2,000 cm3, or where the volume cannot be confirmed, you need evidence the cable meets the Annex C criteria.
- Annex C is now a normative cable pressure test, replacing the informative Annex E of Edition 5. Catalogue data on its own may not be accepted as evidence.
What Actually Changed in Edition 6
The single sentence that carries the change is this: cables and cable entry devices are to be considered together for direct entries into flameproof enclosures. Edition 6 treats the cable, the entry device and the enclosure as one system with one job, which is to stop an internal explosion travelling out through the cable itself.
That is a different mental model from the one most engineers carry. The familiar question is "which certified gland suits this cable?". The question Edition 6 asks is "can this cable, in this enclosure, be entered without a barrier, and what is my evidence?". The gland certificate alone does not answer it.
Three practical consequences follow. The selection is made by the designer rather than the installer. It depends on information about the cable that many datasheets do not publish. And where that information is missing, the standard resolves the doubt in one direction, toward the barrier gland.
How the Rule Worked Before
Engineers who trained on older editions remember a flowchart. The 1996 edition asked whether the enclosure contained an internal source of ignition, whether the gas required Group IIC apparatus, whether the installation was Zone 1, and whether the enclosure volume was greater than 2 dm3. Four yes or no answers, and the flowchart told you whether a plain flameproof entry with a sealing ring was acceptable.
Edition 5, published in 2013, removed that flowchart altogether. Gland selection moved to depend on cable construction rather than on enclosure size or application, with a cable breathing test in Annex E and a minimum external cable length of 3 m. Annex E was informative, which in practice meant it was frequently ignored.
Edition 6 brings back a structured decision, but a better one. The gas group, the cable length, the enclosure volume and the cable performance now sit in a single flowchart, and the cable test that supports it has normative status.
Swipe to see the full table
| Edition | How the entry device was chosen | Status of the cable test |
|---|---|---|
| Edition 3 (1996) | Flowchart on ignition source, gas group, zone and 2 dm3 volume | Not applicable |
| Edition 5 (2013) | Cable construction, minimum 3 m external length | Annex E, informative |
| Edition 6 (2024) | Flowchart combining gas group, cable length, enclosure volume and cable performance | Annex C, normative |
The New Selection Logic
Edition 6 places the decision in Clause 7.5.2 with a supporting table. Read it as three gates in order. If you pass all three, a flameproof entry device with an elastomeric seal is acceptable. Fail any one of them and you are specifying a barrier gland.
Gate One: Minimum External Cable Length
The length of cable outside the enclosure, in the hazardous area, is what allows gas pressure to dissipate before it can travel the full run. Edition 6 sets that minimum at 3 m for Group IIC and for IIB plus hydrogen, and 0.5 m for Groups IIA and IIB.
This is the gate that catches real installations. Short loops between a junction box and a nearby motor, instrument tails, and skid-mounted packages where everything is within arm’s reach all struggle to meet 3 m in a IIC area. Where the length cannot be met, a flameproof barrier entry device is required and no further assessment is needed, because sealing at the point of entry addresses the risk directly.
Gate Two: Enclosure Volume
For Groups IIA and IIB, where the length minimum is satisfied and the enclosure internal volume is below 2,000 cm3, a flameproof entry device with an elastomeric seal is permitted. That covers a large share of ordinary junction boxes and local control stations.
Above 2,000 cm3, the volume alone no longer settles it. Nor does an enclosure whose volume you cannot confirm, which happens more often than anyone admits on brownfield work where the original equipment data has been lost.
Gate Three: Evidence About the Cable
Where the enclosure exceeds 2,000 cm3 or its volume is unconfirmed, the designer needs reliable evidence that the cable meets the Annex C criteria. The standard is explicit that catalogue data may not be sufficient on its own.
In practice this means asking the cable manufacturer for test evidence, and getting a straight answer rather than a marketing sheet. Where that evidence does not exist, the specification defaults to a barrier type device.
Cable length outside the enclosure
3 m for IIC and IIB plus hydrogen. 0.5 m for IIA and IIB. Short runs fail here first.
Enclosure internal volume
Below 2,000 cm3 for IIA and IIB, an elastomeric seal entry is permitted. Above it, or unconfirmed, move to gate three.
Evidence on the cable
Reliable proof against the Annex C criteria. Without it, the answer is a barrier gland.
When a Barrier Gland Is Mandatory
Pulling the three gates together gives a short list of situations where the specification is settled before any product comparison starts.
- The cable run is shorter than the minimumAnything under 3 m external length in a IIC or IIB plus hydrogen atmosphere, or under 0.5 m in IIA and IIB.
- The enclosure is larger than 2,000 cm3 and the cable evidence is missingCommon on larger flameproof control stations and motor terminal boxes.
- The enclosure volume cannot be confirmedTypical on existing plant where the original certificate and data sheet are long gone.
- The equipment certificate or the specific conditions of use demand itAn Ex certificate marked with a condition always overrides a general rule.
There is also a design argument that sits outside the standard. A barrier gland removes a variable from a safety case that has to survive twenty years of modifications, cable replacements and staff turnover. The cable that satisfies the length rule today becomes a shorter run after the next relocation, and nobody repeats the assessment.
Annex C: The Cable Pressure Test
Annex C is the technical heart of the new approach, and it replaces the informative Annex E of Edition 5 with a normative test. The principle is simple enough to explain in a sentence: can gas pressure travel along the inside of the cable?
The test takes a cable sample, pressurises an enclosure to a low test pressure, isolates it, and measures how far the pressure falls over a short interval. A cable that holds pressure is not acting as a pathway. A cable that loses pressure quickly is breathing along its interstices, which is exactly the behaviour a barrier gland exists to block.
The published test uses a 0.5 m cable sample in a 5,000 cm3 enclosure at 0.3 kPa, with a pass where the pressure falls by no more than half after 5 seconds of isolation. Work from the current published text of the standard for the exact method and acceptance criteria before you rely on it in a design dossier.
What This Means on Indian Projects
On Indian sites the installation practice follows IEC 60079-14 through the national adoption, while the equipment itself also needs PESO approval to be used in a hazardous area. Those are two separate questions and both have to be answered.
The practical risk is a mismatch between the two. A gland can hold valid ATEX and IECEx certificates and still be the wrong device under Edition 6 for a particular entry, because the certificate says what the gland is, not whether a barrier is required for your cable and enclosure. Our guide on verifying an ATEX certified cable gland covers the first half of that check, and this article covers the second.
Three habits keep projects clean. Record the entry device decision against each cable in the gland schedule rather than in someone’s head. State the gas group and enclosure volume in the same row. And where a barrier gland is chosen, say which gate drove it, so the next engineer does not unpick a correct decision during value engineering.
Choosing the Right Barrier Gland
Once the barrier decision is made, the product choice follows the cable, not the standard. Two questions settle it: is the cable armoured, and does the installation call for single or double compression?
All four are rated IP66, IP67 and IP68 and are available PESO certified for use on Indian sites. Where the entry does not require a barrier, the standard ranges apply instead, and our comparison of flameproof against weatherproof glands is the quicker way to place those.
Two installation details decide whether a barrier gland performs as certified. The compound has to be packed properly around the separated conductors, without voids, and the gland has to be fitted to a correctly prepared entry. Rushing either one produces a gland that looks right and is not.
Conclusion & Call-to-Action
Edition 6 did not make flameproof installations harder. It made an existing question explicit: can you show that this cable will not carry an explosion out of this enclosure? Where the cable is long enough, the enclosure small enough and the evidence available, a standard flameproof entry remains correct. Where any of those three is missing, the barrier gland is no longer a judgement call.
The teams that will struggle are the ones still selecting entry devices at the installation stage. The teams that will not are the ones recording gas group, cable length, enclosure volume and the resulting entry type in the cable schedule, at design.
Send us the entry list, not just the gland sizes
Give us the gas group, cable construction, external cable length and enclosure volume for each entry, and our technical team will tell you which entries need a barrier gland under the current standard and which do not, with the Exgrip part number against each one.
📩 Talk to our technical team at Exgrip.com
📞 Phone: +91 9537118899
🌐 Website: www.exgrip.com
📩 Request a Quote: Contact Page
FAQs
What changed in IEC 60079-14:2024 for cable glands?
Edition 6 requires the cable and the cable entry device to be assessed together for direct entries into flameproof enclosures, using a flowchart that combines gas group, external cable length, enclosure volume and cable performance. The cable pressure test moved from the informative Annex E of Edition 5 to a normative Annex C.
When is a barrier cable gland mandatory?
A flameproof barrier entry device is required wherever the minimum external cable length cannot be met, which is 3 m for Group IIC and IIB plus hydrogen and 0.5 m for IIA and IIB. It is also required where the enclosure exceeds 2,000 cm3, or its volume cannot be confirmed, and there is no reliable evidence that the cable meets the Annex C criteria.
Does the 2,000 cm3 enclosure volume rule still apply?
Yes, but it is no longer the only test. For Groups IIA and IIB, where the cable length minimum is met and the enclosure volume is below 2,000 cm3, a flameproof entry device with an elastomeric seal is permitted. Above that volume you need evidence about the cable itself.
Is catalogue data enough to prove a cable meets Annex C?
Often not. The standard calls for reliable evidence that the cable meets the Annex C criteria, and notes that catalogue data alone may not be sufficient. Ask the cable manufacturer for test evidence, and specify a barrier gland where that evidence cannot be produced.
Which Exgrip glands are barrier type?
Four models: SCUB for unarmoured cable with single compression, SCAB for armoured cable with single compression, DCUB for unarmoured cable with double compression and DCAB for armoured cable with double compression. All are Ex db, Ex eb and Ex ta rated with IP66, IP67 and IP68 protection, and are available PESO certified.
Does an ATEX or IECEx certificate mean the gland suits my entry?
No. The certificate confirms what the gland is and how it may be used, not whether your particular entry needs a barrier type. That decision comes from the installation standard, based on your gas group, cable length, enclosure volume and cable evidence.