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AlecK

ESR 71: person carrying out inspection must not have - carried out the PEW; - supervised the PEW - issued the CoC for the PEW. What's not forbidden us allowed; so may have designed it (design isn't PEW). And there's nothing there about being employed by the same employer either Because (other than u...

AlecK

More that they are too dangerous to be allowed as a form of step-down. And the greater the step-down; the more dangerous. Which makes then uncommon; which in turn means most of us are not familiar with them At one time it was common to find an ELV work lamp tapped off a motor, eg sewing machines. Ch...

AlecK

Yes, that's what the clause means.
What you need is a step-down transformer with earthed output

AlecK

Most control switches, and all micro-gap switches as generally used for lights, don't meet (a) either. But as gregmcc said, main point in this case is that if it doesn't operate in the "relevant supply" it can't be used as an isolation device for that circuit. Also relays, and most contactors, do no...

AlecK

Not what I was getting at, Doug. Using a line tap couldn't reasonable be considered an alteration to the MEC. (except maybe by EWRB!) Even cutting & joining would be maintenance rather than alteration. (equivalent to replacing a mains entry box?) But re-routing the EMEC to achieve the join is an alt...

AlecK

Agree the terms are widely mis-used (as are many others). Protective earthing & equipotential bonding are two different concepts; and need to be dealt with separately. That said, often the same fittings / conductors are performing both functions - basically wherever there's a protective earth, it al...

AlecK

Yes, for mains in parallel it's the combined CSA that counts;
the CSA of each phase is 2 x CSA of the individual conuctors that make up the phase
Eg 2 x 25 mm Cu = 50 mm total, so MEC 16 mm2

AlecK

I do not believe the proposed action will do anything to reduce the harmonics. To get rid of harmonics requires frequency filters. Questions that affect how the Wiring Rules apply is whose transformer it is, and whether or not it supplies any other installation. Also where is the point of supply? As...

AlecK

Provided it's connected in a way that doesn't adversely affect the integrity of the MEC.
And remember any work on the MEC is "mains work".
which means any alteration to the MEC is high risk PEW and requires inspection

AlecK

Clause 5.5.2.1 covers where PECs can be connected to. Connection to the earth electrode is NOT compliant Clause 5.6.2.2 covers connection of EBC for a water pipe. Connection to earth electrode is not compliant; however Note 1 advises that the EBP in this case(water pipe) can be an extension of the M...

AlecK

There's no simple answer that applies in every case Look at ESR 23. Item (e) says that "domestic or similar" appliances are electrically unsafe of fitted with a plug that does not comply with the relevant Schedule 4 standard. Most of those Standards are either AS/NZS, or IEC with AS/NZS modification...

AlecK

Another example of how poorly "5033: 2012" is written. Better in 2014. Agree those particular words constitute a requirement for location of overcurrent protection. Therefore while they do fit under the overall heading of 4.4 "location and installation requirements"; they should definitely have thei...

AlecK

I presume your reference to "RTI" means "roof top isolator". You would be better to stick to the words used in the requirement ("array switch disconnector" ) rather than sloppy slang. Partly because arrays are increasingly not on rooftops. But mainly because the writers chose to use the particular t...

AlecK

In legal terminology, "person" can be a company or other body corporate. The gist is that if the electricity generated is entirely for use in the installation it's connected to, then work on the generation fittings is excluded from being "mains work". If you're exporting , it could be. And if you we...

AlecK

No compliance issue

AlecK

That bit of the definition (used in connection with generation, for own use ) means that the feed-in from a genset or other non-grid source isn't mains work. Which it otherwise might be, even for an alternative (standby) supply), depending on the configuration of the particular case. For a standalon...

AlecK

Doesn't seem relevant to the topic? Maybe should have started a new thread? --------------------- Unclear what your reference "4.2 distance" refers to. Clause 4.2 is about thermal effects fig 4.2 is about installation wiring vs equipment wiring. Clearances between gas & electricity are covered by cl...

AlecK

Only declared medium risk articles are required to have an SDoC {ESR 83]. DMRAs are generally fittings associated with domestic-type installations. Fittings that are not Gazzetted as DMRA, DHRAs or prohibited, just have to be electrically safe [ESR 80] These requirements all apply to supplying / sel...

AlecK

Assuming domestic, or otherwise following part 2, then ESR 60 requires a standalone power system to comply with "4509.1". Which requires setting up a main earthing system for the installation, including a MEN within the installation's MSB (not within the genset / other source). Basically you can't u...

AlecK

Good luck trying to co-ordinate anything in the few weeks available Q1 replacing a mains entry box is low risk; and within current LoW for EST But not within proposed LoW for EST, assuming the phrasing 'maintenance of work" has any real meaning. Which it doesn't, because you don't maintain "work"; y...

AlecK

Type S are generally 100mA or more, and used mainly for property protection. Whereas RCDs for protection against shock can't be more than 30 mA. When NZ moves to allowing TT supply for some installations, we will need to deal with the lack of reliable discrimination between RCDs in series. Such inst...

AlecK

The exact way the terms apply depends on which of 3 Exceptions to clause 5.3.5.1 is being used. Fig 5.2 illustrates all three, but does not indicate where the POS is (ie where the "installation" starts). It doesn't need to; because that's not relevant to understanding the requirements of the Standar...

AlecK

Correct a tree is not a structure While "3000" doesn't set specific required clearances from vegetation; it does require all external influences that can be reasonable expected to be considered when installing wiring systems, including "flora" (vegetation) [3.1.2 & 3.3.2.9]. Which means the installe...

AlecK

The problem is that ESRs don't allow for the fact that sometimes the MSB is not actually an MEN swbd, because the MEN link is relocated to the (dedicated) sub as permitted by 5.3.5.1 & illustrated in Fig 5.2. Therefore technically there may be no "mains" as defined in ESRs. However it would be most ...

AlecK

Would need the fuse link characteristics to work that out And not sure my brain would be up to it. HRCs are still basically thermal devices, but far different from a simple bit of tinned copper In fact my understanding is that each HRC link is, internally, a whole bunch of small, carefully-engineere...

AlecK

Not my area of expertise either. And I don't like the idea much. However not significantly different from a dual-feed set-up with a bus-tie [Fig 7.1]. I think the suggested configuration will meet requirements for overload protection. Each bit of cable is protected by a suitable device, so cannot ca...

AlecK

There is an underlying requirement to minimise inconvenience in the event of a fault [1.6.5 (a)] . Personally I don't like the use of "minimise"; because minimum means as low as it is possible to get - which would translate to only having one point per RCD. However a fundamental concept of "3000" is...

AlecK

Tho OP didn't state the nature of the equipment; other than it's from America. Therefore will be designed for operation on 60 Hz supply. auto transformer (any transformer) will provide 50Hz output; which may not be suitable. -------------- The need for neutral reference becomes clear if you forget a...

AlecK

my interpretation is that the MPGS includes the inverter (except any 'standby' port), the output cable from the inverter to the installation, and any directly associated fittings such as overcurrent protection, RCDs, isolating switches, or metering.

AlecK

Definition of "mains parallel generation system" in ESR 4. Basically if any fittings can be supplied, at same time, from more than one source; and any of the sources is "generation... for that person's use" ; then it's mains parallel. Note that the term applies regardless of whether any of the sourc...

AlecK

The diagram is incorrect If you have 3 windings connected in star on a 3-phase 400 V supply; there can only be 230 V (approx) across each of them. The 400 V is between phases, not from each phase to earth. L-E voltage is 230 V. Therefore the line terminals should be labelled as 230 V, not 400 V Any ...

AlecK

I would advise following latest available guidance; with 2 provisos. Firstly, do nothing that conflicts with a legal requirement. In this context, don't follow a later edition of it conflicts with the cited edition. That won't happen often, but we need to be careful. Secondly; if following the later...

AlecK

Not aware of any case law - unfortunately. And yes, you might get costs awarded against the Board if you win. On the other hand you might well not; unless you could show not just error but bad intent or improper practice or negligence. So chances are low. You'll also have noticed that there are gene...

AlecK

A good question. As you've noted; the logic of TNC-S seems to require that once you've separated, from a PEN conductor (TNC) to separate N & PE conductors (TNS), you don't change back. However that logic has never? been reflected in NZ Regs / Wiring Rules. Certainly not since 1993. ---------------- ...

AlecK

Any confusion is caused by failure to read the words, and follow the directions; rather than by the words not being clear. As always, we need to read the entire clause; and not just home in on the bit we think we want. However that fact that some people have problems reading this bunch of clauses ha...

AlecK

The expert is usually, but not always, a holder of an Inspector PL. However as for Board members; while we would like to think they are chosen from the 'top end"; we can't really expect that since there are no published criteria for selection. In fact, no obvious basis for being considered to have a...

AlecK

Yes; it still meets the definition of "main switchboard" in ESR 4. However, because ESRs in several cases refer to "the MEN swbd closest to supply (or similar wording), this relocation of the MEN creates problems. EG definition of mains depends in part on them supplying an MEN swbd - but since the M...

AlecK

They appear to rely heavily on the "experts" appointed to assist the Investigators ; but again there appears to be no process for checking that they actually are experts. Sometimes they are not even holders of Inspector PLs. Worth noting that while in this case such an expert prepared a report; they...

AlecK

Given the variables; would be a big & complex thing

AlecK

Completely agree; there is absolutely NO requirement for an isolating switch. Or even for a functional switch.. But since the defendant accepted fault on that point, thus making the same error as the several Board members (who should all have known better), there appears to have been little if any d...

AlecK

That's exactly what they're referring to. And I agree, an RCD does not really protect cable against mechanical damage However, "3000" does permit it as a means of such protection (in those circumstances listed in 3.9.4.2 or 3.9.4.3.2); despite the fact that it doesn't prevent damage from happening t...

AlecK

I do not believe that there is any actual conflict between these clauses.

AlecK

Can't provide a simple answer; but colour isn't the way to tell what to use; what matters will be the type of plastic. The safety data sheets at: https://www.marley.co.nz/technical-docs/safety-data-sheets/ show that the "gold" & "clear" are different mixes of same chemicals ; so presumably intended ...

AlecK

4.10 "electric heating cables for floors and ceilings and trace heating applications." Includes all types of heating cables for all applications (hard to think of anything that wouldn't fit). So whether you call in "in floor", "under-floor", "under-tile" or whatever doesn't matter; it's still a heat...

AlecK

Short answer: No. But I think you're confusing two different requirements. True they both relate to RCDs; but they're about different RCDs installed for different purposes. In 2005 edition; 5.3.4 requires that an inverter must be connected to the installation upstream (on the grid side) of any RCDs ...

AlecK

WRT inspection of earth electrodes: "mains work" includes work on the "main earthing system"; which includes the earth electrode. Therefore ESR 70 (3)(a) requires the inspector to be "satisfied" that the work of installing the electrode has been done in accordance with ESRs. So the compliance of the...

AlecK

WRT main switches: The definition of "mains work" includes work on "mains"; and that definition is "fittings forming part of an installation that are used for the supply of electricity to the MEN switchboard that is closest to the point of supply. "fittings" includes conductors but is not limited to...

AlecK

Scope of "5761" is not restricted to plug-in only. However it is restricted to "household & similar" appliances. 2.4.1(e) lists "fitted with a plug conforming to AS/NZS 3112" as one of the steps to be undertaken "prior to sale". This is unclear; because it's not a complete sentence. It seems to say ...

AlecK

Fig 5.2 illustrates the configuration when the MEN is located i.a.w these Exceptions. Note that the MEC still has one end connected to installation main earth bar. The other end is connected to the substation earth bar; to which the electrode is also connected. Basically the whole "main earthing sys...

AlecK

ESR 80(3) provides a pathway to "deemed safe" for used appliances.
True it's tagged "for purposes of this regulation"; so technically can be relied on for sale / supply; but not necessarily for simply installing.
But it's the best you'll find.

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