P
Patrick Griffin
Hi all,
I am hoping someone can clarify if my understanding on earth fault loop impedance testing is correct.
A low efli is needed so a protective decive can operate in the required time, the lower the z the quicker it will operate.
ZE= External resistance from borad to supply, board isoltated, main earth disconnected, test between incoming phase on main fuse and disconnected main earth.
ZS= Board live, main earth connected, test between out going live from main fuse and earth terminal. Zs must also be carried out on the furthest point on each circuit.
R1+R2= The maximum measured resistance of phase and earth on any circuit, lighing or sockets etc
ZS= ZE (R1 + R2)
What i would like to know is firstly is the above correct and if not where am i going wrong?
Thanks very much
I am hoping someone can clarify if my understanding on earth fault loop impedance testing is correct.
A low efli is needed so a protective decive can operate in the required time, the lower the z the quicker it will operate.
ZE= External resistance from borad to supply, board isoltated, main earth disconnected, test between incoming phase on main fuse and disconnected main earth.
ZS= Board live, main earth connected, test between out going live from main fuse and earth terminal. Zs must also be carried out on the furthest point on each circuit.
R1+R2= The maximum measured resistance of phase and earth on any circuit, lighing or sockets etc
ZS= ZE (R1 + R2)
What i would like to know is firstly is the above correct and if not where am i going wrong?
Thanks very much