In recent times there has been an increase in the use of portable generators as standby supply for installations by a detachable lead. While the installation is relatively simple, there are some critical aspects that members need to be aware of in regard to the earthing requirements.
Clause 220.127.116.11.1 of AS/NZS 3000:2018 requires the MEN connection to be at the switchboard of the installation. There should not be a MEN within the generator.
There is no requirement for an earth electrode at the generator, as the frame earth is connected to the installation's earthing system.
The changeover switch shall switch the generator neutral but shall not switch the normal supply neutral, as per figure 7.5 below.
In addition to this, it is a requirement of clause 4.2.6 of AS/NZS 3010:2017 to permanently mark the inlet fitting to indicate its purpose. The following wording must be used:
Isolated output generating set only.
RCD protected and centre tapped generating sets shall not be connected.