Upgrade Required?

[Chopper]

We have a rural customer who after been told by the network that poles and a transformer on their property need replacement at customers cost have decided to go off grid. Inspector says switchboard will need upgrade as its old style with no RCD protection and therefore not suitable for inverter supplied power as protection devices wont operate . Looking for advice on this subject

[AlecK]

There's no specific requirement for an upgrade; the parts of the installation not altered can remain in service as per ESR 113.
But there can be problems arising from change to off-grid supply; and ESR 13 requires that any work done does not make any other part of the installation any less safe.

The problem with the existing circuit protection is that while overload protection will work exactly the same on the inverter (or genset) for an off-grid supply; the source may be unable to provide enough current for operation of overcurrent devices used to provide fault protection and / or short circuit protection. Operation within relevant time limit requires very high currents; and local generation systems generally can't provide enough.

Adding RCDs will deal with fault protection, as RCDs don't need high fault currents to operate within time limit.
But RCD can't proved short circuit protection; so something further will be needed.
Some inverters have electronic s/c protection built in.