Imported Coffee Cart WoEF

[Slovett]

I have a job coming up where an Imported Coffee Cart (Transportable Installation) is needing a WoEF.
Because it's imported I'll need to Check Over Section 8 of 3000 + Appendix C 3001.

I've already been told by the Electrician on site that the continuity of the Earths on the power points are reliant on the Chassis. ie Earth from 16A Inlet goes straight to the Chassis, then each Earth from each individual power point is connected to the Chassis directly behind each power point which therefore solely relies on the chassis for the continuity of the whole earthing system of the Coffee Cart.

Is this allowed? I've had a skim through 3001 and can't find anything (at this stage) that prohibits using the Chassis to connect each power point earth to the earth from the Inlet Earth, as long as the Earth Resistance is within acceptable levels - I've said all Earths should be joined together (ie Common lug or earth Bar), but thought I'd better check here first, and hopefully someone can prove me right or wrong, before I end up costing someone a lot of money for remedial work that may not need to be done.

Thanks


EDIT - 3001 - 3.5.1.1 (b) says The protective earthing Cable Shall be effectively connected to the Appliance inlet and to the Earth Terminal of the permanent connection point in or on the Transportable structure - I would not expect the Chassis to be classed as an Earth Terminal?

[TPower]

Think you need to refer to Part 1 of 3000 & appendix C of 3001 only.

Being an imported CI, it’s “issued in accordance with AS/NZS 3001, but only after an assessment for compliance with Part 1 of AS/ NZS 3000” as per ESR78(2)(c)

Don’t think you should be referring to Section 3 of 3001.

Some parts of appendix C direct you to section 8 of 3000, clause C7.2 for example.

I believe it should have ‘earthing conductors’ rather than rely on the structures chassis. Clause C7.5 indicates this “Socket-outlets shall have effective continuity of all earthing conductors…”

[Slovett]

You're right sorry, I left out Part 1 by mistake.

[AlecK]

Agree there 'should' be earthing conductors for each circuit, rather than individual fittings each earthed to the chassis.
But I can't see that it's an absolute requirement.
It's a Part 1 matter vie 1.5.5.3 fault protection by automatic disconnection of supply; where (a)(i) requires use of a 'protective earthing conductor" [1.4.79].

In Part 2, 5.3.2 covers permitted materials / types for PECs
And 5.3.2.2(iii) permits use of a conductive frame that's used for mounting the equipment being earthed.
But that doesn't extend to running a PEC from a fitting that's not mounted on the frame to the frame instead of all the way to the earthing system.
That's Part 2, not Part 1; but it shows that in at least some cases a conductive frame can be used as the PEC and comply not only with Part 1 but also with Part 2.

The key issue here being safety: is the impedance low enough for the protection to operate within required time?
For what it may be worth; I don't like the idea much, but with the clear guidance in Part 2 about use of frames as PEC I can't see a good reason to say it's non-compliant.

Basically it's up to you to determine whether the imported CU complies with Part 1.
Your name / number of the WoEF - and can be hauled before the Board for perceived errors / omissions.
So don't sign it off unless you are absolutely happy that it does comply.
The other option always available is to just walk away

Similarly it's not required for imported CIs to comply with every requirement in Section 3; those are for work done in NZ, not for work done overseas.

[gregmcc]

Just done one a few weeks back, failed really badly, last item on this list of repairs that I wanted to see done was a copy of COC from the electrician that does the repairs - I got a blank look from the customer.......(yes I knew dam well that the owner of the coffee cart was not an electrician and he was the one who "tried" to bring the coffee cart up to standard)

[AlecK]

Can understand wanting to see a CoC - but it's not required that we sight one and we have no right to demand a copy.
CoC is not required for work done overseas.
And even if we see one, it doesn't remove any responsibility or liability from us when we're issuing a WoEF.

[Slovett]

Thanks for your feedback - I've got them to replace the Earthing back to the switchboard earth bar. (EDIT) Previous Earth resistances where around 2ohms or greater.

- I have a further question regarding single insulation.

The whole installation has been wired in Single insulated conductors. (I've found a voltage rating on one of the cables 400/700v) passing through steel structure inside walls. I can't find anything in Part1 mandating double insulation. Being steel everything is earthed. To me it complies with 1.5.4.3 (Basic Insulation), it also complies with 1.5.5.2 (Earth structure protected by MCB -1.5.5.3 (a)) and also 1.5.6 (which augments 1.5.4.2 (a))

The only potential issue I have is the single insulated conductors between the 16A inlet to the switchboard, as you can never guarantee the supply will have RCD protection.

I'd prefer double insulated conductors throughout the installation, but at this stage, I can't find anything to back me up.

Also a power point under the sink that controls a Hot tap in the sink. There are no visible voltage ratings on the Power point and no voltage ratings or IP ratings on the Electric Tap.

Thanks

[AlecK]

Even if adequate (under Part 1) to cause operation of the protective device RCD); 2 Ohms is a fail under App C [C7.5] which ets max 0.61 for 16 A rated.
Single insulation upstream of RCD is also a fail: C6.10(b)

From the pics I say the wiring fails 1.7.2(a), due to no protection from rubbing on the sharp edges of the holes thru the metal.

Energy Safety have published an opinion that 1.7.3 requires sockets to be AS/NZS type. I believe they're wrong, since 1.7.3 is about "deemed to comply with 1.7.1"; not a "must comply".

That said; I think there are issues at higher level than just the WoEF assessment.
I believe that the sockets are illegal. They're DMRAs and also DHRAs, so need SDoC and approval for sale / supply in NZ;
and that multi-fit config is unlikely to have either.
Similar for the cables, and the protective devices.
The question is whether ESRs 83, 84, etc apply to sale / supply as part of an larger assembly, or only to sale / supply individually.
And if imported directly by the 1st user, these rules might not kick in until the unit gets on-sold.

Remember also that definition of CI includes appliances, so they all have to be checked as well.



A while back I had a mobile kitchen that had been directly imported, supposedly compliant with "3001", and had very similar issues.
Certainly far from compliant with "3001"; and failed several aspects of Part 1 and many in App C.
I said that before I would issue a WoEF, everything downstream of the inlet needed to be ripped out and replaced.
Including the lights and other appliances.
Never found out how much actually was replaced, but at least it didn't have my name on it.

[Slovett]

Thanks AlecK.

The only 'Imported' appliance left in the install is the Electric Tap. Everything else has been replaced with new NZ compliant appliances (Hot Plates, Fridge etc.) which I have tested. All Power points have been replaced with NZ type. The only power point left is the under sink power point, which will be replaced / deleted.

You're right about 1.7.3. Even if they installed insulated grommets at the entry to the power point, I have no idea of how the cables have been installed within the walls (ie rough edges of steel frame etc). They have to run new earths externally, so they may as well re-wire the whole thing while they're at it.

Thanks again

[AlecK]

There's a plan to replace the Part 1 assessment with a set of particular checks depending on what Standards the imported CI was wired to.
The checks will be in next edition of "3001"; but will also need a change to ESR 78 before they can come into effect.
Unfortunately there was almost no feed-back on the specific checks & tests, during 2 rounds of Public comment.

Also depends on there being some sort of original certification of compliance
So should be useful for eg caravans / motorhomes ex UK.
But won't help with this sort of crap installation that never complied with anything.
I'm guessing this one was from PRC?