I'm not sure I ever remember seeing them. You might be able to view them in the IET Library.

Some of us do have extensive technical libraries ourselves ...  can we be of assistance in helping look something up for you (or indeed, we may know the answer off-pat, you never know) ?

Where abouts is this library? I’m just wondering when regulation 521.5.1 came in. I wanted to look it up in the 17th and 16th….

IronFreely said:

Where abouts is this library?

The IET library is at Savoy Place in London (some titles, though, they can post out to Members).

My library is associated with my home office!

IronFreely said:

I’m just wondering when regulation 521.5.1 came in. I wanted to look it up in the 17th and 16th….

Which para are you looking at specifically? Eddy currents (paras 1 and 2), or the "parallel cpc" (para 3)?

We'll have to look back further than 16th Edition when talking about eddy currents. The first 2 paragraphs are effectively very old and can be traced back to the 15th Edition pretty much in their current form, but prior to that, 14th Edition had a similar Regulation B.100 for  conductors of AC metal conduit.

Para 3 (clearly permitting parallel cpc for armoured cables) was not present in BS 7671:2018, but came in at 17th Ed Amendment 1 (BS 7671:2018+A1:2011). It is interesting to consider, though, under what conditions a parallel cpc may or may not be useful (for example, whilst it would definitely be OK to consider it for faults downstream of the SWA+cpc combination, for buried SWA cables, where we have a fault line (or lines) to armour following severing of the cable, the parallel cpc may well be ineffective).

If you let me know, I can provide some more info on the bit you're interested in, expanding on the above.

The library is in the IET building - between the Embankment and the strand in London. however, to save you the time you have 3 choices. Whcich did ou want, mechanical forces, trunking flammability or cable types - the same bit of the regs has been all of these over the last few editions.

Leaning heavily on the way UK copyright law allows reproduction of extracts of copyrighted documents  for study or criticism, here is a chance to compare and to criticize the numbering schemes...

17th Edition

521.5 A.C. circuits: electromagnetic effects
521.5.1 Electromechanical stresses
Every conductor or cable shall have adequate strength and be so installed as to withstand the electromechanical
forces that may be caused by any current, including fault current, it may have to carry in service.

16th edition 2001 version

or 15th

The library is in the IET building - between the Embankment and the strand in London. however, to save you the time you have 3 choices. Whcich did ou want, mechanical forces, trunking flammability or cable types - the same bit of the regs has been all of these over the last few editions.

Leaning heavily on the way UK copyright law allows reproduction of extracts of copyrighted documents  for study or criticism, here is a chance to compare and to criticize the numbering schemes...

17th Edition

521.5 A.C. circuits: electromagnetic effects
521.5.1 Electromechanical stresses
Every conductor or cable shall have adequate strength and be so installed as to withstand the electromechanical
forces that may be caused by any current, including fault current, it may have to carry in service.

16th edition 2001 version

or 15th