In general these generators are designed to switch off when the electricity network supply is disconnected.

This is a safety feature of the protection systems installed within these devices. This feature protects the generator itself and ensures the generator does not create a potential hazard by making the external electricity network live in a fault situation.

It is however possible for certain generators to be installed in such a way that they can be operated when the electricity supply is disconnected. To do this the premises must be physically isolated from any connection to the external electricity network. This is a safety requirement under the National Standards Authority of Ireland (NSAI) Wiring Regulations and requires a changeover switch and other alterations to internal wiring within the premises to permit safe operation of such generation. More information on these generators, including what would be required to enable this in your own premises, can be obtained by contacting a registered Safe Electric electrician, a suitable generator installation company or by contacting a generator equipment manufacturer directly.