Ze

[mikhailfaradayski]

John the rating of a domestic MCB is 6kA that is it's breaking capacity, (in theory if the current exceeds that it may suffer from a disruptive failure) The nominal voltage is 230V Ohms law should then tell you the minimum Z for the supply to that equipment.

Thanks. Needles to say, I understand all that, but maybe you haven't seen how today's onslaught on me started.

Onslaught? Dear oh dear John, you can be quite the drama queen when you want to be. I thought you enjoyed hypothetic style debate?

Although it wasn't my intended meaning, something I wrote was taken to mean that that I was suggesting that the only thing that mattered about the Zs of a circuit was that it was low enough to achieve the required disconnection times. I was therefore challenged with "even if Zs <0.04&#937; ?" - presumably a reference to the fact that PSC rises to >6kA at just below 0.04&#937;. There was therefore an apparent expectation on the part of that electrician that a Ze low enough for PSC to exceed 6kA was not beyond credibility.

Thats nothing more than pure conjecture on your part there John. I am in-different to the existence of such a PFC, it may exist, it may not.

For those who are not aware of what was actually written which kicked this debate into life, it can be seen here:-
//www.diynot.com/forums/electrics/zs-too-high.317292/

then to my post dated - Tue Mar 20, 2012 1:15 pm

 

[JohnW2]

Overall I can recommend this: ... Costs less than the trade-in value of your BRB.

Thanks. I actually already have a copy. Was this a general recommendation, or did you feel it had some specific relevance to matters being discussed in this thread? (On the face of it, this discussion has not required calculations beyond trivial applications of Ohm's Law).

Kind Regards, John.