electricalforum.nz

Just looking at the definitions in the Act and Regs

The scope of 3001 includes up to 1000v but does this mean in the eyes of NZ legislation that any three phase transportable structure isn't actually classed as a connectable installation? Or am I missing something?

'3001 scope includes all transportable structures supplies at LV - the reference to 1000 V is simply reminding is of what LV is.
Remember this is referring to voltage to earth, but even if it wasn't our normal 3-phase supply doesn't exceed 100 v between phases.

Also - as always - it's not the scope of a cited Standard that decides whether or not something has to comply; rather it's the citation of that Standard via Act & Regs. If ESRs say something must comply with a particular Standard; a limitation on the Scope of the cited Standard can't over-ride that regulatory requirement. Which is actually a legal requirement; because the Act sits at an even higher level, and requires compliance of electrical work with ESRs.

In this case ESR 60 requires all "connectable installations" (other than pleasure vessels and mobile medical) to comply with "3001".
The definition of"connectable installation" is in the Electricity Act; then modified slightly by ESR 7.
Any vehicle or transportable structure capable of receiving an external supply at LV by detachable connection (being plugged in) fits the definition.
From memory; the definition of "vehicle" is in the Road Transport Act, and is very wide.

There's certainly nothing in any of these documents that excludes multi-phase.

Ah, right, how do we know it's voltage to earth? Is that to do with the definition of standard low voltage? 230V P-N?

1.4.98 specifies "voltage between conductors, or between conductors and earth";
split into 3 ranbes: ELV, LV, & HV

So - by either criterion - our normal 400 between/ 230 to earth is within the range for LV.

Apologies Alec, just had a re look over this and just to be 100% clear because it hasn't been definitely mentioned but it was ESR7 and the fact it says "connection to an external power supply that operates at a nominal voltage
between 90 and 250 volts AC at standard low voltage"

Incase that changes anything and if not then my second question was more direct at how can we come to the conclusion that the 90-250V specified here is voltage to earth

I don't disagree three phase items falls within the scope of 3001 and I definitely understand the differences between ELV, LV and HV but it was more that ESR7 has thrown me off

Thanks

You need to look at definition of SLV
You'll find it's just a closely defined sub-set of LV.

The point of ESR 7 isn't to exclude multi-phase; just to exclude supplies outside the narrow range of SLV
True it doesn't specify voltage to earth, but I don't think it's reasonable to take any other interpretation.

Thanks Alec, appreciate it

I suppose as you say "connection to an external power supply that operates at a nominal voltage
between 90 and 250 volts AC at standard low voltage" external power that opperates at 90-250 at SLV

SLV "in respect of electricity supplied by either a single-phase MEN system or
a multiple-phase MEN system, a nominal voltage of 230 volts AC
between phase and neutral"

So I guess it's saying ESR7 includes those that when at a nominal voltage of 230V L-N (or L-E essentially as you said) supply voltage, are supplied at between 90v-250v, which they definitely would be with our 230V +/-6%