Need help from our Aussie electrical techs

We have an ATEX control panel in Darwin. We had to connect an ATEX horn and beacon to two M25 threaded entries left in panel for these external devices. Local inspector is questioning our method.



NEC maintains that the seal must be located within 18" of devices that requires a seal off. Further more it states that the only thing that is allowed to be in between the seal off and the panel are explosion proof fittings such as RE bushings, unions, nipples, etc.



We used M25 to M20 adapter, union, 90 degree exp fitting, short rigid nipple then sealoff (puts sealoff 6" from panel).



I assume galvanized rigid conduit is an approved wiring method in Australia for zone 2 locations. I further assume (hope) similar termination guidelines (like NEC reference above) exist.



If anyone could provide Australian current code article number that might apply, please do. In retrospect, we should have just used IEC cable and EExd glands. Thanks in advance..

Sorry but we are a different country, so you will have to explain the acronyms. NEC (That is one I do know) does not apply here as N stands for national not international. If you could explain what an ATEX is, we might be able to help. Regards Alan Case

Alan, I may have given more information than needed and further confused the issue.

FYI, ATEX is a European certification for explosion proof panel.
NEC is National Electrical Code (USA)

The real issue is;

I have a electrical control panel. It is rated and has been approved for installation in a zone 2 hazardous area. There are no questions about the panel. It is now located in Darwin. We used some standard explosion proof rated (USA)gavanized rigid conduit fittings to connect to a external horn and beacon.Are the above described wiring methods acceptable in Australia?

Could you provide your local code article reference number(S) that pertains to the installation of rigid conduit in zone 2 hazardous areas?

Could you provide your local code article reference number(S) that pertains to the installation of sealoffs (safe seals) in zone 2 hazardous areas? I am talking about the requirements of sealoffs (safe seals) when entering a flameproof enclosure.

For example, in USA NEC (electrical code) that information is clearly laid out in article 500.

Thanks in advance for any assistance.

This is the standard I think you require.

AS 2380.1-1989/Amdt 1-1998 : Electrical equipment for explosive atmospheres - Explosion-protection techniques - General requirements

From http://www.standards.com.au/catalogue/script/Details.asp?DocN=amdm000569911

Unfortunately it does cost but you can get it via a download.

Regards Alan Case

Alan, thanks for your attempts at help.

I went there and was even able to download for free. However the link was just one page of a generic amendment to the code (?) concerning equipment in exp areas.

What I am concered with are allowed wiring methods within exp (explosive like zone 1 or 2) areas. In the USA, We have the NEC. It is our electrical code book. It states the basic accepted guidlines that must be followed for a safe electrical installation. It is one book, revised every three years.

Do you have a national code book for electrical installations in Australia? What is the latest edition? Is there an article number, page number or chapter that would apply to wiring methods within exp areas? Thanks..

Robert,

If you can let me have your e-mail address, I can send you a copy of the Australian Standards HB13 "Electrical Equipment for Hazardous Areas" which gives you an overview of the requirements and references the relevant Standards you will need to refer to. Unfortunately, there is not just one book that covers everything. It's too big (1.8Mb)to post in this forum.

The standards you will probably need to refer to will be the AS 2381 series.

Are you sure the panel is OK ? I have had a lot of trouble using equipment with foreign certifications (ATEX BASEEFA etc) and have in the past had to replace them or shell out big bucks to get the equipment certified by an Australian Testing Authority. You don't say if the horn and beacon are intrinsically safe or otherwise explosion protected (exd,exq,exe etc.)

Hope this helps, Tim.

Equipment intended for use in Potentially Explosive Atmospheres (ATEX)

Named after the French "ATmosphere EXplosible".

I have just finished our company ATEX handbook for EU regulations and if the panel is in the hazardous area then the connection to the horn and beacon have to be to the same spec as the panel enclosure so if its an EExd or EExe enclosure then us metal conduit with EExe or EExd fittings. If the panel is in the safe zone then use conduit sealed at the device end and at the zone boundary. alternatively use armoured or double insulated cable such as HO7 RN-F and use EEXd cable glands. In zone 2 there is a lot of room for manouvre. For our zone 2 applications we generally use zone 1 rated equipment or IS barriers (zone 0)as trying to figure out a correct zone 2 installation is just too difficult as the EU standard is not that clear.

If you can let me have your e-mail address

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Done. Thanks Tim, check your private email.

Are you sure the panel is OK ?

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Yes. We had very specific technical specifications to adhere to and none of which have been questioned. Both the Horn and Beacon are zone 2 IIe (increased safety, zone 2 rated) In fact, I just found out they have the Australian approval (ANS?)as well. They are MEDC brand XB11 and DB3 cat numbers.

In zone 2 there is a lot of room for manouvre. For our zone 2 applications we generally use zone 1 rated equipment

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It is zone 2 area. We supplied zone 1 EEXD IP66 rated control panel. What is in question (at this time) is our wiring method from this EEXd zone 1 flameproof enclosure to the zone 2 IIe rated horn and beacon. Hopefully I will find guidance to approved wiring methods in technical data Tim is sending. I guess, worse case scenario, we could just send replacement cable (1 meter) with enough glands to replace existing piping.

This is a personal observation. If an inspector is involved the "code" wont matter, in a sense. Usually "code" is open to interpretation so an inspector can determine the "method" required. In the long run it may save time/money etc if you just do it the "inspectors" way.

Here is some useful stuff on ATEX equipment. This from the company we use a lot for IS barriers.


http://www.mtl-inst.com/mtlsupport.nsf


Look under Technical papers for TP1110.

Why not make it easy and put a cable between the panel and the horn. 2 Exd glands will make that work

I have had a look at that beacon it is EExd IIB which means it is explosion proof so needs an exlosion proof connection to the enclosure or explosion proof glands and cable. It is zone 1 or 2. Equipment for zone 2 only is EExn. As its EExd it means that the internal electrics are not required to be low energy, as it works by containment, so IT IS IMPORTANT that you use EExd fittings. I would recommend a short length of armoured cable and EExd cable glands. Your conduit method is ok too but all of it must be EExd rated.