Compliance with IECEx 60079-14 and ANNEX E

[Nicola Zeffiro]

Good morning everybody,
I'd like to have a clarification regards the normative IECEx 60079-14 and its ANNEX E.
As far as the installation is concerned at paragraph 10.6.2 it specifies that if I meet the requirements

b) Cables and glands meeting all of the following:
– cable glands comply with IEC 60079-1 and are certified as equipment
– cables used comply with 9.3.2(a)
– the connected cable is at least 3 m in length

the installation is in compliance with the norm itself.
My question is, in this condition I can not say that the cable is gas tight, can I?
To state that a cable is gas tight I should test the prototype of cable under the conditions ANNEX E requires, which are the followings:
E.1 Test procedure
A piece of cable with a length of 0,5 m should be type tested when installed into a sealed
enclosure of 5 l (± 0,2 l), under constant temperature conditions. The cable is considered
acceptable if the time interval required for an internal overpressure of at least 0,3 kPa (30 mm
water gauge) to drop by 0,15 kPa (15 mm water gauge) is not less than 5 s.
The enclosure must be completely tight to avoid pressure loss through the enclosure gaps.

My client requires a GAS TIGHT CABLE in compliance with 60079-14, so unless I'm very much mistaken, I should give him/her a cable which satisfy the conditions dictated in paragraph 10.6.2 (that regards the installation methods too) and the ANNEX E as well, so I must test the cable under those conditions.

Thank you for Your attention

Nicola

 

[Gr8blu]

Nicola: Annex E defines the requirements for the "gas tight cable" itself. What that really means is that gas cannot pass through/under the cable jacket and/or between the conductors. The main section (60034-14) defines the means to prevent gas ingress into the enclosure - by entering wherever there is a possible opening in the surface (i.e. a pass-through for insulated - or un-insulated - conductors and/or sensor elements). To meet the intent of the customer requirement as you've stated it, you must meet BOTH conditions. Having a certified test result from the cable manufacturer may be enough for your end user, but you may also have to test the cable assembly yourself, as the user may construe the termination method as a possible gas ingress point.

Converting energy to motion for more than half a century

 

[Nicola Zeffiro]

Thank you so much for your answer.

In case I DO NOT have the request from the Client to consider a gas tight cable (ANNEX E), but just the following installation conditions:

the cable connects two devices in the same zone (Zone 1) but with different type of protection i.e. Ex d and Ex e


Do I need to consider a gas tight cable or is it enough to follow these installations directives?

the cable complies with 9.32 a (round, non-hygroscopic...)
the gable gland is certified as an equipment and comply with 60079-1
the cable is more than 3 m in lenght


P.S. By saying so I'm assuming that once a cable meets the requirements of ANNEX E , it is fully in compliance with 9.3.2 a of 60079-14, as for sure it is circular and compact, it doesn't allow gas to flow through it and futhermore the cable can be less than 3 m in lenght and and the cable gland doesn't need to be certified as a flame proof equipment

Thank you

 

[Gr8blu]

Nicola: I might be wrong, but I think that if the enclosure at one end of the cable is "Ex d", then the gland at that end must be part of the "flameproofing". What this typically means is either a gland that is not combustible or ignitable - or has sufficient length to prevent a flame from inside the enclosure reaching the exterior environment. For the other (Ex e) end, the requirements for a cable and gland are generally easier to meet.

Converting energy to motion for more than half a century