Ai and 7671

lyledunn said:

During practical training, the lads are encouraged to collaborate with each other and use said documents to check test results and design data. I note many just defer to their smart phone to access even rather obtuse data buried in the bowels of 7671

It's a really tricky situation, because AI gets things wrong.

However, without AI, there is also incorrect and out-of-date data available on the internet ... so, as an assessor or examiner, how do you know whether to mark it right or wrong (it's right to the data the candidate used ... but was that valid?)

I make this point quite sincerely, as I know that, at least until recently (and it may well still be the case), a reputable organisation has available, at least through a quick search, for maximum measured earth fault loop impedance of some protective devices for which data is no longer published in BS 7671, but the data does not account for C_min. I am also led to believe some earth fault loop impedance data is available from earlier editions of BS 7671, which takes into account neither C_min, nor the drop to 230 V from 240 V.

Using bona-fide current electronic versions of the standard (and permitted guidance) would allow easier searching for answers, BUT qualifications bodies do have strict rules about the use of electronic devices.

lyledunn said:

During practical training, the lads are encouraged to collaborate with each other and use said documents to check test results and design data. I note many just defer to their smart phone to access even rather obtuse data buried in the bowels of 7671

It's a really tricky situation, because AI gets things wrong.

However, without AI, there is also incorrect and out-of-date data available on the internet ... so, as an assessor or examiner, how do you know whether to mark it right or wrong (it's right to the data the candidate used ... but was that valid?)

I make this point quite sincerely, as I know that, at least until recently (and it may well still be the case), a reputable organisation has available, at least through a quick search, for maximum measured earth fault loop impedance of some protective devices for which data is no longer published in BS 7671, but the data does not account for C_min. I am also led to believe some earth fault loop impedance data is available from earlier editions of BS 7671, which takes into account neither C_min, nor the drop to 230 V from 240 V.

Using bona-fide current electronic versions of the standard (and permitted guidance) would allow easier searching for answers, BUT qualifications bodies do have strict rules about the use of electronic devices.

Just entered "C_min." and look at the google answer.  Not quite what you would expect.

CliveS said:

Not quite what you would expect.

"typically valued at 0.95 to account for voltage variations." ... well, generally in the UK with supplies to ESQCR (at the moment), yes ... BUT not across CENELEC countries that adopt EN 50160, where C_min is "typically 0.9"  ... 

The source for this isn't BS 7671, but EN 60909-0.