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From the electric vehicle thread there it seems is a problem where TN-C-S and TT earth systems are close together and some one can be subjected to a steep voltage gradient or even two separately bonded devices of differing voltages in excess of safe parameters under fault conditions.
To isolate under these conditions could a variant of the old ELCB-v be used?
My problem is it is the earth connection which is the danger and to isolate the line, neutral and earth of the PME supply would go against the idea of not having an earth through any breaker.
So thoughts please. It could just switch of supplies leaving earth wires connected but would this remove the danger? It could just ring a bell or light a light to warn.
So where supplies to caravans, cars, or boats require a TT supply but it's close to a TN-C-S supply can some warning or disconnection device be used to stop or reduce the danger of earthing systems of different voltage?
This includes the idea of using a ELCB-v with the two connections across the earth diodes so if the diodes fail the supply would trip.
To isolate under these conditions could a variant of the old ELCB-v be used?
My problem is it is the earth connection which is the danger and to isolate the line, neutral and earth of the PME supply would go against the idea of not having an earth through any breaker.
So thoughts please. It could just switch of supplies leaving earth wires connected but would this remove the danger? It could just ring a bell or light a light to warn.
So where supplies to caravans, cars, or boats require a TT supply but it's close to a TN-C-S supply can some warning or disconnection device be used to stop or reduce the danger of earthing systems of different voltage?
This includes the idea of using a ELCB-v with the two connections across the earth diodes so if the diodes fail the supply would trip.