Whether a circuit will actually disconnect in time ZS
A Type C breaker tolerates half the loop impedance a Type B does. Swapping one in to stop nuisance tripping can leave a circuit that no longer disconnects.
The circuit
The cable
The resistance per metre is yours, from your copy of the tables. The list here is a convenience and is meant to be checked: a figure invented by a web page could size a cable that burns.
Whether it disconnects
The same rating in three types
The working
How it works
ZS checks whether a circuit will disconnect in time under fault, from its earth fault loop impedance. It gives the maximum Zs, applies the 0.8 rule and says how long the run may be. The figures stay in this tab.
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