In AS/NZS 3000:2007 Fig 5.2 shows a HV Customer Substation supplying a Main Swb (no MEN link) are the conductors supplying this swb "mains" ?
ESR reg 4 has the definitions of "mains" and "mains work" both refer to connecting the conductors to a MEN switchboard.
If the POS is the substation then, no? Have I just answered my own question?
Thanks Peter
Mains Work
Re: Mains Work
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 unwise to do anything other than treat the A(s) & N conductors from sub as "mains", and the PEC as MEC.
The intent is clear, even if the writers of ESRs (mostly lawyers rather than people who know the subject) didn't get the words quite right.
Therefore technically there may be no "mains" as defined in ESRs.
However it would be most unwise to do anything other than treat the A(s) & N conductors from sub as "mains", and the PEC as MEC.
The intent is clear, even if the writers of ESRs (mostly lawyers rather than people who know the subject) didn't get the words quite right.
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Re: Mains Work
You have answered your own question, some of the conductors in the main swb (if before men board) will be mains until they connect to the men board.PeteRig wrote: ↑Wed Sep 22, 2021 11:58 amIn AS/NZS 3000:2007 Fig 5.2 shows a HV Customer Substation supplying a Main Swb (no MEN link) are the conductors supplying this swb "mains" ?
ESR reg 4 has the definitions of "mains" and "mains work" both refer to connecting the conductors to a MEN switchboard.
If the POS is the substation then, no? Have I just answered my own question?
Thanks Peter
Re: Mains Work
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 Standard
If the substation is part of works, Exception 3 applies; and the installation's MSB has no MEN. Instead the MEN is within the substation.
The POS will be downstream of the MEN, and it follows that there will be no " fittings forming part of the installation that are used for the supply of electricity to the MEN swbd that is closest to the point of supply" (ie, nothing that fits the definition of "mains").
Another possibility is that the installation is fed at HV; and the POS is upstream of the (dedicated) substation.
Exception 1 applies; and the "mains" will include (most of) the substation.
The other relevant clause is 5.5.1.1, which allows for the installation's MEC to be run to a sub instead of to an earth electrode.
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 Standard
If the substation is part of works, Exception 3 applies; and the installation's MSB has no MEN. Instead the MEN is within the substation.
The POS will be downstream of the MEN, and it follows that there will be no " fittings forming part of the installation that are used for the supply of electricity to the MEN swbd that is closest to the point of supply" (ie, nothing that fits the definition of "mains").
Another possibility is that the installation is fed at HV; and the POS is upstream of the (dedicated) substation.
Exception 1 applies; and the "mains" will include (most of) the substation.
The other relevant clause is 5.5.1.1, which allows for the installation's MEC to be run to a sub instead of to an earth electrode.