Hi folks.
Can someone clear this one up please.
Exisitng TNS system to a domestic, max permissable Ze is 0.8 ohms.
So if there was a fault immediately after the cutout head 230v/0.8 ohm a fault current of 287 amps would flow, if the PD was 100 amp BS88-2 it would take 100 seconds to operate (BRB p296).
Cant be right!
Can someone clear this one up please.
Exisitng TNS system to a domestic, max permissable Ze is 0.8 ohms.
So if there was a fault immediately after the cutout head 230v/0.8 ohm a fault current of 287 amps would flow, if the PD was 100 amp BS88-2 it would take 100 seconds to operate (BRB p296).
Cant be right!