Ze 'too low'

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If Zs is low enough to satisfy disconnection times, then that it surely 'it' as far as that consideration is concerned, and I'm almost certain that no-one could find any regulation which said otherwise.
What if the Ze was <0.04 ohm?
I don't understand how that affects what I said - can you explain?

I presume that if one appears to have a very low Ze, one needs to think about where the supply is coming from (distance to transformer) and, if necessary, question the accuracy of one's measurement - after all, with a TN supply in 25mm², 0.04&#937; would only allow for about 23m to the transformer

Kind Regards, John.
 
Would you like me to hand feed you the answer, or would you just like a little clue to help you towards self-enlightenment. (I find the latter to be far more satisfying)
 
Would you like me to hand feed you the answer, or would you just like a little clue to help you towards self-enlightenment. (I find the latter to be far more satisfying)
Clues would be fine. If they prove to be beyond me, we can resort to hand feeding.

Kind Regards, John.
 
ok, you say no-one could find a reg (as per your opening quote)....

your starter for ten>>>>

Taking my response to be true (Ze<0.04 Ohm), then i say reg 133.2 could very easily become a problem in a standard domestic install.
 
ok, you say no-one could find a reg (as per your opening quote)....
What I said was that, as far as considerations of disconnection times is concerned, I didn't think anyone could find a reg which would require a Zs lower than the maximum which would achieve the required disconnection times (the comment being discussed was, after all, 'Zs too high') ... and, as far as I am concerned, that remains true regardless of the Ze. Do you disagree?

If you want to start a discussion about high PSCs, in relation to a situation which you hypothesised, perhaps you should start a new thread?

Kind Regards, John.
 
ok, you say no-one could find a reg (as per your opening quote)....
What I said was that, as far as considerations of disconnection times is concerned
That is not what you said. There really isn't any need to erroneously paraphrase that which can be seen above. It is clear what you did say.
, I didn't think anyone could find a reg which would require a Zs lower than the maximum which would achieve the required disconnection times (the comment being discussed was, after all, 'Zs too high') ... and, as far as I am concerned, that remains true regardless of the Ze. Do you disagree?
John, unlike a verbal conversation where it is a bit easier to back track as its easier to fudge (due to the reliance upon the contemporaneous memories of the persons involved in the discussion) the actual conversation by saying something like' ah, but i didn't say that, i said this' or 'you must have mis-heard me when i said...', you have engaged in a written discussion. Therefore every comment (unless surreptitiously altered) remains to seen, and can be seen verbatim.
If you want to start a discussion about high PSCs, in relation to a situation which you hypothesised, perhaps you should start a new thread?
I have no desire to do that, do you?
 
oh BTW, almost forgot 10 points for you for getting there.

Also, wrt that rather unclear statement which you asked whether i agreed or not. It was just a bit too rumsfeldy for me to really know whether i agree with it or not. Maybe you could rephrase?
 
ok, you say no-one could find a reg (as per your opening quote)....
What I said was that, as far as considerations of disconnection times is concerned
That is not what you said. There really isn't any need to erroneously paraphrase that which can be seen above. It is clear what you did say.
Indeed, it is very clear what I did say, namely (with emboldening added):
If Zs is low enough to satisfy disconnection times, then that it surely 'it' as far as that consideration is concerned, and I'm almost certain that no-one could find any regulation which said otherwise.
In what sense did what I wrote subsequently represent an 'erroneous paraphrase' of the original?
If you want to start a discussion about high PSCs, in relation to a situation which you hypothesised, perhaps you should start a new thread?
I have no desire to do that, do you?
Not really. I was talking about regulations concening disconnection times (and 'too high Zs'), but, for some reason, you introduced a comment ('clue') which I presume was meant to relate to PSC in the presence of very low Ze. I therefore thought that you perhaps wanted to discuss it.

Kind Regards, John.
 
after all, with a TN supply in 25mm², 0.04&#937; would only allow for about 23m to the transformer
Im sure there are many dwellings spread around the country which have a sub <23m away. Probably more so in urban areas/cities, wouldn't you agree?
 
( I can't really believe I'm having to type this out as it is already written above )

-You said if 'Zs is low enough for disconnection times' then that is 'it', nothing more to consider.
-I say it is not 'it', there is more to consider.
-I say, you need to consider the potential damage that could be done by a very, very low Zs.
-I put this to you in the form of a short question.
-You failed to see why it affect your statement.
-Your failure is not my problem, but i had hoped to enlighten you as to your error.
 
Also, wrt that rather unclear statement which you asked whether i agreed or not. It was just a bit too rumsfeldy for me to really know whether i agree with it or not. Maybe you could rephrase?
I don't really see why you should find it unclear, but I'll try to spell it out for you (with some inevitable repetition, to help you understand):

I was saying that, if Zs is low enough to satisfy the requirements for disconnection times then that is 'it' as far as considerations of disconnection times are concerned. In other words, the regs are fully satisfied (in relation to considerations of disconnection times) if the Zs is low enough to achieve those disconnection times. I therefore added that I didn't think that anyone would be able to find a regulation which required a Zs lower than the maximum that would achieve the required disconnection times.

... very long-winded, and I think my original much briefer version conveyed exactly the same meaning, but do you now understand the question - i.e. do you agree?

Kind Regards, John.
 
Good grief, you are obvioulsy in playful mode today!

You said if 'Zs is low enough for disconnection times' then that is 'it', nothing more to consider.
... with the qualification "as far as that consideration [[i.e.disconnection times]] is concerned"-
I say it is not 'it', there is more to consider. -I say, you need to consider the potential damage that could be done by a very, very low Zs.
I refer you to the my above-mentioned qualification to what I wrote. I agree with what you're saying about 'very very low' Zs, but that has nothing to do with what I said about disconnection times.

Kind Regards, John
 
after all, with a TN supply in 25mm², 0.04&#937; would only allow for about 23m to the transformer
Im sure there are many dwellings spread around the country which have a sub <23m away. Probably more so in urban areas/cities, wouldn't you agree?
I really don't know - you tell me! It undoubtedly happens and, as use say, it's going to be more common in urban areas ... but not only urban. Even in my tiny, very rural, village, there is a sub-station immediately adjacent to one dwelling, so that is presumably going to be <23m cable for that dwelling, but I suspect that is the only dwelling that will have a cable run of less than 23m from that particular transformer.

All I was saying was that, if one gets a very low Ze measurement, one should consider how far it is to the transformer, in order to decide whether the reading one is seeing is credible.

Kind Regards, John.
 
Good grief, you are obvioulsy in playful mode today!
I'm always playful, it gives me a great sense of well being and an inner warmth.
You said if 'Zs is low enough for disconnection times' then that is 'it', nothing more to consider.
... with the qualification "as far as that consideration [[i.e.disconnection times]] is concerned"
This is the first time you have included the 'i.e. disconnection times' bit. Up until now you seem to have been talking about the only consideration regarding Zs is to ensure dis. times are met, there is nothing more to consider. I put it to you that there is more to consider. I told you why. You didn't understand.
I say it is not 'it', there is more to consider. -I say, you need to consider the potential damage that could be done by a very, very low Zs.
I refer you to the my above-mentioned qualification to what I wrote. I agree with what you're saying about 'very very low' Zs, but that has nothing to do with what I said about disconnection times.

Kind Regards, John
 
after all, with a TN supply in 25mm², 0.04&#937; would only allow for about 23m to the transformer
Im sure there are many dwellings spread around the country which have a sub <23m away. Probably more so in urban areas/cities, wouldn't you agree?
I really don't know - you tell me!
OK.
There are many houses spread across this country which are closer than 23m from the supplying sub. The frequency that such houses can be seen will undoubtedly increase proportionally with urban density. That seems very obvious to me, but maybe not so to you.
 

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