Installation with inverters

One other thing to watch is if the installation has an inverter. Mostly these are grid-connect units for “mains parallel” operation; and as such are required to have “anti-islanding” to prevent back-feed onto the grid when it goes down. DON”T alter this set-up.

A multi-mode inverter is capable of also operating in “island” mode; but to take advantage safely we have to take this output through a changeover device same as any other “alternative supply” and use an extra pole of the device to change the mode of the inverter.

But regardless of what type of inverter; don’t set up an inverter and a genset to run in parallel.

It may seem logical to disconnect the mains, and use a genset to simulate mains supply so the inverter will operate; but the two forms of source don’t work together. AS/NZS 3010 requires generators providing alternative supply to be isolated from any inverter by the source selection device (changeover switch).

If setting up an emergency generator for an installation with an inverter; arrange the generating set to supply it’s own separated-off part of the installation only.

The TB doesn’t specifically cover setting up an emergency supply from an inverter; but logically the same principles should apply. And the declaration that emergency supply work is “general” rather than high risk PEW can be interpreted as covering emergency supply from an inverter. So if the inverter that’s there is a multi-mode type; it should be OK to disconnect and safely terminate the mains before changing modes. Issue a CoC for the change. Change it back, with another CoC; before reinstating the mains supply.