electricalforum.nz

Hi guys
Have 216 apartments (spread over two story blocks) in a very tight area, any issue if 2 dwellings share the same earth electrode enclosure (each unit has its own earth stake), each apartment is only 4m wide so would end up with 216 enclosures otherwise.
The design is that each dwelling has its own mains from underground Network tuds.
Each apartment Main Earth will be identified in the enclosure
Cheers

You can have both sharing the same electrode.
There's no requirement for an electrode to be exclusive, only the main earthing conductor and connection to the electrode that needs to be exclusive.

Thanks Doug, so two houses in a street could share the same earth electrode technically?

5.3.6.1 requires that "an electrode" be used to connect each installation's earthing system to mass of earth.
this implies a single electrode, but later clauses specifically allow multiple for particular circumstances.
Similarly 5.5.1.1 requires the MEC for each installation to be connected to "an electrode".
5.5.1.2 sets requirements for this connection.


There's no specific prohibition on sharing electrode between installations;
but it's not generally accepted as good practice.
The whole point of the "MEN" system is that "M" stands for 'multiple" earth connections on the neutral of the distribution system
that means one at origin, and one for each installation; so that overall there is low impedance between N & mass of earth.
The more electrodes, the lower the overall impedance.

There are also non-electrical considerations, such as having an legal easement (or equivalent) that allows cabling for installation in one property to run across another property. So if these apartments are on unit tiles, could get very complicated.
Though luckily that's generally not our concern.
Similar for underground mains along a common driveway; typically each house has a share of the driveway width,
and the mains for each should run only in that houses' part of the drive (not in a common trench).

Each apartment having own mains from TUD suggests that this is a bunch of individual installations,
and not a "multiple electrical installation" (where there would be only one lot of mains, and only one MEC / electrode; with submains for each apartment.

Thanks Alec and Doug, appreciated