Neutral Query

[murphy4869]

Was looking at the sticky to see what earthing arrangement I had and was just curious by the diagram for the TN-S, if someone could enlighten please,

I see the live is protected by the main service fuse but the neutral just flows back normally, is the neutral still isolated when the main service fuse is pulled as the live completes the circuit or am i getting confused.

Thanks

 

[ban-all-sheds]

1) The situation you describe is the same whether it's TN-S, TN-C-S or TT.

2) Neutral is not isolated when the main fuse is pulled, but as it's at 0V, more-or-less, wo earth that's not really a problem. Although technically neutral is a live conductor....

 

[briwire]

only the live must be fused.

Imagine if both live and neutral had a 60Amp fuse and a high overcurrent fault developed. Its a 50% chance that the neutral fuse would blow, leaving the live fuse intact. So there would still be 230v present in the installation.