If you have a standalone outdoor Main Swb IP rated on a concrete plinth on a site (point of supply is upstream), that has multiple fuses to supply Dist cabinets on this site, from these Dist Cabinets, mains go to apartments located in multiple blocks (separated by land). Each block for example may have 8 apartments, each apartment has an MEN Swb c/w an earth electrode.
The question I have, these 8 apts located on the same floor slab, under the same roof, same structure, do they fall under the definition of an outbuilding, as the block of 8 apts are fed power from a Main Swb located upstream?
The engineer is saying that as each apartment is completely separated by fire rating materials, therefore the block of 8 is not an outbuilding even though under the same roof etc and feed from a Main Swb upstream. AS/NZS3000:2018 does mention a definition about outbuildings, under on roof etc.
Thoughts please, if it is an outbuilding you are not allowed multiple MEN's?
Outbuilding definition
Re: Outbuilding definition
If the main switchboard is on the concrete plinth then all the outgoing feeds are submains
5.5.3.1 (b)(I) prevents there being more than one MEN link in the outbuilding
Outbuilding is definited by 1.4.69, I believe it meets this definition
Doesn't sound compliant to me
5.5.3.1 (b)(I) prevents there being more than one MEN link in the outbuilding
Outbuilding is definited by 1.4.69, I believe it meets this definition
Doesn't sound compliant to me
Re: Outbuilding definition
My thoughts also Jamie, but the engineer is going down the track that the apts are not in an outbuilding due to the construction of the fire rated walls etc. If he is prepared to make it a certified design then ok. Thanks.
Re: Outbuilding definition
For purposes of '3000"; ESR 4 (2) specifies that a term used in a Standard has the meaning used in that Standard, unless either the Act or ESRs provide a different definition.
There's no definition of 'outbuilding" in either the Electricity act or ESRs; so the word takes the meaning used in '3000".
Which is defined @ 1.4.69.
The critical aspects are that there must be two physically separate structures, with one getting it's electrical supply from the other.
A block of flats / shops / whatever that's physically separated from the structure containing the switchboard that supplies it can be regarded as an outbuilding for purposes of "3000".
There may be a different definition under Building Act and / or Regs; but that does NOT apply for electrical work.
There's absolutely nothing in the definition in "3000" about fire separations; so they simply are not relevant.
In practice, the only difference it makes is that you can use a PEN submain to supply an outbuilding; under clause 5.5.3.1(b).
As Jamie says, there can only be one MEN in any outbuilding. So each apartment having MEN swbd and electrode is non-compliant;
assuming the PoS is at / upstream of the MSB that supplies the cabinet you've called the MSB.
However if the POS for each apartment is the dist cabinet it's fed from; then what you've got is a "private works" arrangement;
with the network supplying the first cabinet, and it supplying the other cabinets, and the "mains" for each apartment starting at the fuses within those cabinets.
Under that scenario, you can have multiple separate installations within each block of apartments; and each has it's own MEN and MEC (they can share a common electrode).
No different from a high-rise scenario; just horizontal instead of vertical - commonly called "rising mains", not actually not "mains" at all in most cases.
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2018 edition (not yet cited) goes further; and only allows the option of PEN submains as long as there's only one supply to the outbuilding. I there's more than one supply, it is a "combined outbuilding" and each submain to it must include a PEC, with NO N-E links and NO electrodes at the outbuilding. While that's not enforceable yet in NZ; there are very good reasons for the restrictions, so they should be followed.
There's no definition of 'outbuilding" in either the Electricity act or ESRs; so the word takes the meaning used in '3000".
Which is defined @ 1.4.69.
The critical aspects are that there must be two physically separate structures, with one getting it's electrical supply from the other.
A block of flats / shops / whatever that's physically separated from the structure containing the switchboard that supplies it can be regarded as an outbuilding for purposes of "3000".
There may be a different definition under Building Act and / or Regs; but that does NOT apply for electrical work.
There's absolutely nothing in the definition in "3000" about fire separations; so they simply are not relevant.
In practice, the only difference it makes is that you can use a PEN submain to supply an outbuilding; under clause 5.5.3.1(b).
As Jamie says, there can only be one MEN in any outbuilding. So each apartment having MEN swbd and electrode is non-compliant;
assuming the PoS is at / upstream of the MSB that supplies the cabinet you've called the MSB.
However if the POS for each apartment is the dist cabinet it's fed from; then what you've got is a "private works" arrangement;
with the network supplying the first cabinet, and it supplying the other cabinets, and the "mains" for each apartment starting at the fuses within those cabinets.
Under that scenario, you can have multiple separate installations within each block of apartments; and each has it's own MEN and MEC (they can share a common electrode).
No different from a high-rise scenario; just horizontal instead of vertical - commonly called "rising mains", not actually not "mains" at all in most cases.
-----------------------
2018 edition (not yet cited) goes further; and only allows the option of PEN submains as long as there's only one supply to the outbuilding. I there's more than one supply, it is a "combined outbuilding" and each submain to it must include a PEC, with NO N-E links and NO electrodes at the outbuilding. While that's not enforceable yet in NZ; there are very good reasons for the restrictions, so they should be followed.
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