Well, I'll kick off the debate on SPDs. Once again, the emphasis seems to be on domestic (we all, or virtually all of us live in a home of one sort or another) so are the proposals an improvement or not?
I find SPDs an addition with little reason behind it. They have no "safety case" for PEOPLE at all. Electrical supply systems have always had transients present (although there do seem to be more now) and they did not cause a problem. "Electronics" is often used as a reason why they are necessary, but this is nonsense, any failures can always be found in poor design of the failed electronics! I think that the problem trying to be cured is that the change to LED lighting has put much more poor electronics into homes, and LED lamps have very simple design which is susceptible to transients because the manufacturer has saved tiny amounts of money, although the selling price is quite high. Again the fixed wiring regulations are being asked to fix problems elsewhere. This trend is very noticeable on car charging (RCDs), PME (additional earthing), domestic appliances (AFDDs), surges (SPDs) etc. I do not find that VSDs, SMPS in professional kit, quality computers, induction hobs etc, suffer failures due to surges or transients on the mains. The DC power connectors do not suffer from transients despite working on EHV lines and during thunderstorms. This problem is largely illusury and BS7671 is not the place to change anything.
I find SPDs an addition with little reason behind it. They have no "safety case" for PEOPLE at all. Electrical supply systems have always had transients present (although there do seem to be more now) and they did not cause a problem. "Electronics" is often used as a reason why they are necessary, but this is nonsense, any failures can always be found in poor design of the failed electronics! I think that the problem trying to be cured is that the change to LED lighting has put much more poor electronics into homes, and LED lamps have very simple design which is susceptible to transients because the manufacturer has saved tiny amounts of money, although the selling price is quite high. Again the fixed wiring regulations are being asked to fix problems elsewhere. This trend is very noticeable on car charging (RCDs), PME (additional earthing), domestic appliances (AFDDs), surges (SPDs) etc. I do not find that VSDs, SMPS in professional kit, quality computers, induction hobs etc, suffer failures due to surges or transients on the mains. The DC power connectors do not suffer from transients despite working on EHV lines and during thunderstorms. This problem is largely illusury and BS7671 is not the place to change anything.
