Is stand alone system inspectable

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Dan L
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Is stand alone system inspectable

Post by Dan L »

Is a stand alone generator system as shown in fig 7.6 inspectable.

its a generator supplying an MEN SWITCHBOARD.

ESR reg def of mains work mentions

"does not include—
(i) work on fittings that are used or intended for use by any person in,
or in connection with, the generation of electricity for that per-
son’s use and not for supply to any other person; or"

Its my understanding that conductors, earthing and men are all fittings so does that make a stand alone generator system excemt from mains work, as long as it meets criteria of only for that persons use which is a bit vauge. Imo, just for that person's use? What if a second person charges their phone then would it first need inspected?

If some could she'd some light on this wouldbe much appreciated.
AlecK
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Re: Is stand alone system inspectable

Post by 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 standalone power system; there will be no "mains"; because no PoS .
Definition of "mains" says they originate at PoS, and end at the MEN swbd closest to PoS.
(Generally interpreted as meaning they end at line terminals of main switch(es) for actives, and main N-bar for N)

However there will still be a "main earthing system" (as defined: electrode, MEC & MEN link).
The MES is not used in connection with generation, so is not excluded from being "mains work".
So work on the MES is "mains work"; which is high risk, so must be inspected.
Dan L
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Re: Is stand alone system inspectable

Post by Dan L »

Oh OK " in connection with generation" being the key part

I understand. Thanks much appreciated
Dan L
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Re: Is stand alone system inspectable

Post by Dan L »

per-
son’s use and not for supply to any other person; or"

Does this mean only for personal use?

So if it supplied power to public or building site it would be high risk?

Read it over and over and makes less sense every time to me
AlecK
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Re: Is stand alone system inspectable

Post by 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 were setting up a generator-in-common for a group of installations, it could be.

Not the generation itself - note there's no reference to generation in paragraph (a); and if it isn't mentioned there then there's no way the work can be "mains work".
I don't know for certain why the reference to generation in para (b)(i) is there; but I presume someone wanted to cover some obscure / uncommon arrangement. Maybe for where the generation crosses a boundary, and so arguably creates a PoS, which in turn brings in the definition of "mains" and from that we get to "mains work".
Equally it might simply be that it was written by a lawyer who had no understanding of what they were writing this rule about.

But there's little point getting tied in knots over the exact meaning.
For what you're doing, you won't be relying on this exclusion.
Instead you'll be working on the far simpler basis that there are no "mains" for a normal standalone power system; therefore no "mains work" under (a)(i).

You'll still have a "main earthing system", and work on that will be "mains work" under (a)(ii) & (a)(iii).
If it's maintenance "mains work", then it will be low risk; but installation "mains work" will be high risk and so require inspection.
Dan L
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Re: Is stand alone system inspectable

Post by Dan L »

Thanks much appreciated
Slovett
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Re: Is stand alone system inspectable

Post by Slovett »

Came here to ask this exact question - Thanks!

To to further on from the question - I've obviously missed a definition somewhere. But why isn't a Generator / Inverter considered a PoS in terms of Mains, when it is the sole supply of Electricity in an off grid system? I would have assumed the cable supplying the installation from the Gen. would carry the same amount of risk as a Standard 'Mains' cable?
PeteRig
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Re: Is stand alone system inspectable

Post by PeteRig »

In AS/NZS 4509:1 clause1.4.12 has the definition of "point of supply"
"output terminals of the standalone power system"
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Re: Is stand alone system inspectable

Post by JamieP »

Point of supply is defined in the Act so overrules that definition Pete
AlecK
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Re: Is stand alone system inspectable

Post by AlecK »

Yes; ESR 4(2 ) says any definition in Act or ESRs over-rides a definition of same term on a Standard.

It can work the other way also, as per ESR 4(3);
with terms used in ESRs, but not defined in act or ESRs, carrying definitions from "3000" (for installations) or IEC 60050.

Therefore "electrical installation", "mains" , "POS" etc are all as defined in the higher-level documents.
As a result, for a standalone, there is no POS, and as a result there are no "mains'".

This can sometimes create a glitch when trying to follow a Standard, as the different definitions can affect the way requirements apply.

"POS" is a good example. The definition on 4509.1 is different from the one in "3000", which is different from the one in ESRs.
We have what could be 4 different places that the term can be applied to.
In "3000" a POS can either be connection to a network, or connection to a source within the premises.
4509.1 only has the source option - but not limited to within the premises, and could be ELV.
But for ESRs a POS always relates to a network; but isn't necessarily a connection point
- often part-way along a run of cable, where it crosses the boundary;
which has the slightly weird effect that the same conductors are "mains' downstream of the PoS, but not "mains" - and not part of the installation - upstream of it

So it simply doesn't work to apply the ESRs definition to what "4509" calls a POS.
One is a connection to a network, and the other is a connection to a generating source under circumstances where there is NO connection to a network
The only practicable option is to use the Standard's definition for purposes of the Standard, and the ESRs' definition for purposes of ESRs.
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