Hello everyone,
What are the advantages/disadvantages of using TN-S system with and without Neutral conductors?. Where does it find its application?


Hello everyone,
What are the advantages/disadvantages of using TN-S system with and without Neutral conductors?. Where does it find its application?
It is not that the neutral is omitted.. in first case Neutral is combined with protective earth and in the second case , both are separate.
Perhaps it looks that way. But in TNS no loads will be connected between a Live and a protective earth (*), while a load current will flow in a neutral, if it is needed, as part of normal operation, not just during a fault.
TNS without neutral is not to be confused with TNC, where we do allow a shared neutral and earth, but at least in the UK, only permitted for distribution networks, and with additional precautions taken. - you cannot have an RCD-like function in a TNC system, as fault current and load currents share a wire.
Mike
(*) Well, it is sometimes seen actually, but is very naughty - load currents flowing in the earthing wiring are considered a very bad thing, and in a well designed system Automatic Disconnection of Supply (ADS) will operate in some form to remove the power should the earth current be more than a fraction of a percent of the full load current.
It is not that the neutral is omitted.. in first case Neutral is combined with protective earth and in the second case , both are separate.
Perhaps it looks that way. But in TNS no loads will be connected between a Live and a protective earth (*), while a load current will flow in a neutral, if it is needed, as part of normal operation, not just during a fault.
TNS without neutral is not to be confused with TNC, where we do allow a shared neutral and earth, but at least in the UK, only permitted for distribution networks, and with additional precautions taken. - you cannot have an RCD-like function in a TNC system, as fault current and load currents share a wire.
Mike
(*) Well, it is sometimes seen actually, but is very naughty - load currents flowing in the earthing wiring are considered a very bad thing, and in a well designed system Automatic Disconnection of Supply (ADS) will operate in some form to remove the power should the earth current be more than a fraction of a percent of the full load current.
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