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Posted By Topic: Machine testing standards

Mar 09 2020 11:50

Hi there, needing some clarification as to our ccurrent tests we carry out on our industrial machines we build for the dry powder packaging factories industry.

The machines we build are 63amp 3 phase supply and have multiple hazardous zones within which we comply to as/nzs 60079.14 and the test reference we usually use to test our machine would be that of 3100:2017. Looking at the ESR schedule 4(1) it says that AS/NZS 60335.1 or a part 2 is relevant to household appliances or similar but i dont believe we are anywhere near that as our machines are built for industrial use in powder packaging factories both here in NZ and around the world. For around the world we build to the relevant local standards i,e, NFC/UL or CE for europe. But for the ones in NZ i want to make sure we are in fact testing to the correct standards and seeing the ER not referencing to what we usually test to being AS/NZS 3100:2017 makes me a little concerned as to which standard i should be testing to?

For instances if we arent testing to as/nzs 3100:2017 then lets look at the other angle to my tests which someone here had a perfect layout of references so have copied here:

AS/NZS 3000 Clause (b) directs you to clause 7.7 with regards to bonding requirements for an explosive atmosphere.

AS/NZS 3000 Clause states AS/NZS 60079.14 as the installation standard.
Testing to be carred out as per AS/NZS 3000:2007 Section 8.3 with specific reference to bonding being the below instead of 1ohm as per AS/NZS 3100:2017 -
AS/NZS 3000 Clause states that a bonding conductor shall be no more than 0.5 ohms.

AS/NZS 60079.14 Clause 6.3.1 states Potential equalization is required for installations in hazardous areas. For TN, TT and IT systems, all exposed and extraneous conductive parts shall be connected to the equipotential bonding system. The bonding system may include protective conductors, metal conduits, metal cable sheaths, steel wire armouring and metallic parts of structures, but shall not include neutral conductors. Connections shall be secure against self loosening and shall minimise the risk of corrosion which may reduce the effectiveness of connection.

It can be seen from the above that the bonding in a hazardous area can be achieve by numerous Means including the Protective Earth, and the SWA of cables and also by physical contact of the device to the metallic part of the structure. I assume that as long as you have a maximum of 0.5 ohms between the metal case of the Ex device and the bonding ring main conductor then you have achieved the bonding requirements.

From the above, would you agree my test references will be fine to reference the above for testing going forward or would you agree that AS/NZS 3100:2017 (which esr referes to as a household appliance standard) should be the standard we reference our tests and build to?

Too many different opinions from different sparkies have lead me to this confusion with the esr not referencing the standard that the company test documents refer too is also adding to the confusion and also not being clear enough as to when building industrial machines with hazardous zones (or even without hazardous zones) the esr doesnt have a good indication as to what category we fall under.

Appreciate any feed back. Thanks

Mar 09 2020 14:06

Agree your machines don't fit within the "household & similar" description.

Wiring inside the machines you make would be equipment wiring.
3000, 60079.14, etc are Standards that apply to installation wiring; rather than to equipment wiring. However the same principles will apply WRT avoiding any explosive atmospheres being ignited by electrical energy.

I suggest you should contact Energy Safety for further advice as to what Standards it would be appropriate for you to test & certify to.

Mar 09 2020 15:55

60079.14 applies to all electrical equipment, not just fittings defined as installations. There are specific requirements for portable appliances for instance.

To the OP, most of the "machines" I have come across in Hazardous Areas are treated as installations once they are in place. Is your machine supplied from a plug or permanently connected once on site?

Mar 10 2020 08:39

Yes the Scope of 60079.14 covers all eqjuipment used within a hazardous area. however it is written mostly from an installations viewpoint, as indicated by the wording of the title.

More to the point, from OP I believe the issue is not about equipment to be used within a hazardous area, but about a hazardous area that exists within the equipment - which will restrict the options to at least some degree.

I would suggest that first step would have to be "area classification"; to establish the extent of the hazardous areas. If any of the Zones extends beyond the confines of the equipment, then there will be complications with where & how the equipment can be installed.

Mar 10 2020 08:56

Thanks guys, this is what i received from Work safe via Veerendra Bhim
Technical Officer, Energy Safety
High Hazards, Energy & Public Safety when i gave them the run down and i dont believe the answer he has given me is correct hence why ive turned here for some other inputs so i can go back to him and ask some further questions.

He replied:"If you refer to this link it makes reference to AS/NZS 60335.1 or a part 2. AS/NZS 60335.1 is mentioned in Schedule 4(1) of the ESR. See below extract".

I clearly said to them that we build machines which include hazardous zones within so when i got this response i was kinda like, that doesnt sound right.

The sparky i have taken over has this standard 3100 down as his reference in all the test documents which i am here questioning it saying we should be referencing to as/nzs 3000 and 60079.14 but would like to confirm this before we change our documents.

However, i am happy enough to site ESR 60(1) The following installations or part installations must be installed, tested, inspected, and connected so as to comply with Part 2 of AS/NZS 3000 and also with the standard indicated: - (b)
an installation or part installation in a hazardous area: AS/NZS 60079.14:



Mar 10 2020 09:16

Also regarding how the machines are installed on site is all dependent on the site sparky. We always request a hard wired dedicated 3 phase supply (depending on size of machine varies in size of supply - the bigger ones can be max demand up to 63 amps where as the little ones can be max demand 32 amps) hard wired to our FHV board where the main isolator is positioned which is detailed in our drawings for the sparky. We also request a single phase ups supply which if supplied also goes to our FHV board hard wired to the main 4 pole isolator.

Zones for our bigger machines are broken up into 5 zones, and its mainly 1 zone in particular which is the filler/bag loader area that has intrinsically safe circuits within.

Mar 10 2020 13:16

Do you guys rely on the separate Ex certificates for the different equipment or do you have 1 Ex cert that covers the whole machine?