ban-all-sheds said: ↑
That is really going to depend on the definition of "energise". .... But when you intentionally supply something which in normal operation creates a potential difference between the cpc and true earth so that you intentionally cause current to flow in the cpc......
JW2: OK - so you appear to be saying that the BS7671 definition of a live conductor (live part) does, or may, include CPCs. Is that correct? ....
That is really going to depend on the definition of "energise". .... But when you intentionally supply something which in normal operation creates a potential difference between the cpc and true earth so that you intentionally cause current to flow in the cpc......
JW2: OK - so you appear to be saying that the BS7671 definition of a live conductor (live part) does, or may, include CPCs. Is that correct? ....
Well, I have never looked at, or considered, what the definition of a live conductor or a live part is. Nor "energise".
But if doing something which causes current to flow in a conductor is not "energising" it, then what is it, and what is "energising"?
Whatever the definitions say, or do not say, I really don't see how one can look at 543.7 and not see requirements associated with situations where the cpc is expected to carry current in normal operation.
ban-all-sheds said: ↑
I'm sure it is.
JW2: Fair enough - so you agree that the authors of BS7671 did not intend that the definition of a 'live conductor' should include CPCs? ...
I'm sure it is.
JW2: Fair enough - so you agree that the authors of BS7671 did not intend that the definition of a 'live conductor' should include CPCs? ...
I would say so, on the grounds that all sorts of things become a nonsense if it does, and the classification becomes almost pointless because what conductors would then not be live?
ban-all-sheds said: ↑
So maybe those who claim a definition for "live conductor" which ends up making a cpc one should reconsider their definition rather than falsely claim that cpcs are not intended to carry current during normal operation.
JW2: Maybe. I certainly don't know where 'intended to carry current during normal operation came from.
So maybe those who claim a definition for "live conductor" which ends up making a cpc one should reconsider their definition rather than falsely claim that cpcs are not intended to carry current during normal operation.
JW2: Maybe. I certainly don't know where 'intended to carry current during normal operation came from.
It came from this exchange:
bernardgreen said: ↑
Then so is the CPC a Live conductor, or do the electrons change uniforms when they cross the border between Neutral tails and CPC in the cutout ?
Risteard said: ↑
No it isn't. It is a protective conductor as it is not intended to carry current during normal operation.
Then so is the CPC a Live conductor, or do the electrons change uniforms when they cross the border between Neutral tails and CPC in the cutout ?
Risteard said: ↑
No it isn't. It is a protective conductor as it is not intended to carry current during normal operation.
To which I pointed out that 543.7 is stuffed full of things you have to do when you expect the cpc to carry current, and we all know how Risteard took that.
But again - look at what 543.7 says, and the words it uses. It's not talking about abnormal or fault conditions. It says things like "... total protective conductor current is likely to exceed ...". Something which is likely is something which is normal.
JW2: However if, as above, you think that the BS7671 definition of 'live conductor' does/may include CPCs, yet are sure that such was not the intention of the authors, are you suggesting that they simply got the definition wrong?
Something is wrong. If the definition of a "live conductor" means that a cpc is sometimes one, and that is not the intention, then the definition must be wrong.