Are CU SPD's worth it?

which seems to be at risk of representing an unwelcome intrusion on 'freedom of personal choice'.
As an electrician, what can I do but follow BS7671.
The technical staff at the IET are a bit reactive, yes when it comes to surge, (and possibly RCDs) just look at all that nonsense in chapter 44 with the risk assessment calculations in the initial 18th edition. That was all soon dropped.
Is this is a freedom of personal choice issue, not sure if hordes of people will gather in Trafalgar square demanding the freedom not to have a surge device fitted.:giggle: But I get your point
I don't think I like the analogy to an insurance salesman, that makes people following the guidance sound a bit insincere.
Even though I do have doubts about some of the thinking of the 7671 committee, I do presume they have good technical knowledge.

Re the OP. He was worried about his expensive equipment being damaged, by surge. Is it snake oil to suggest that fitting an SPD will help mitigate some risk, and therefore , has done the best he can, and gain a bit of peace of mind.
 
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As an electrician, what can I do but follow BS7671.
In practice, probably not a lot - which is why I would have expected you to have been as 'worried' as I am to see it drifting into areas which really have nothing to do with 'electrical safety' in the usual sense?
The technical staff at the IET are a bit reactive, yes when it comes to surge, (and possibly RCDs) just look at all that nonsense in chapter 44 with the risk assessment calculations in the initial 18th edition. That was all soon dropped.
Quite so.I was pretty amazed by that stuff, for the relatively brief period it was there. So, who knows - if enough people were to 'express doubts' about SPD's, maybe they would 'drop the requirement' - but I can't really see that happening!!
Is this is a freedom of personal choice issue, not sure ...
Well, as I attempted to argue, it's not really any less a restriction of personal choice than it would be to compel people to 'insure' their washing machine/whatever "for peace of mind". It is surely for individuals to decide what approach to their possessions is necessary/appropriate to give them 'peace of mind', isn't it?
I don't think I like the analogy to an insurance salesman, that makes people following the guidance sound a bit insincere.
"Insincere" to whom/what? If it were not for what the authors of BS7671 have written would you be 'sincerely' advocating/advising the fitting of SPDs, as you effectively did in post #11? If not, then who/what were you be 'sincere' to when you wrote/advised what you did - seeming not 'sincere to yourself'?
Even though I do have doubts about some of the thinking of the 7671 committee, I do presume they have good technical knowledge.
That's a constant 'interesting question'. JPEL/64 certainly has a lot of collective knowledge/experience, yet some of what they 'decide' can seem difficult to reconcile with that. It took them decades to realise that, by not considering the fact that supply voltages were less than 'nominal' in a very substantial proportion of installations, they were potentially leaving that substantial proportion of installations with less than the degree of fault protection which they 'required'. As I've discussed at length in the past, I also think that they problem got their 'basic electrical thinking' wrong in relation to supplementary bonding.

Maybe some of the problem relates to the problem which arises when something is written by a (very large) committee, regardless of the individual intelligence and knowledge of individual members of the committee - i.e.I wonder what BS7671 would look like had it been written by one 'very knowledgeable and wise' person (or a very small group of such people)?

Another problem is that, quite apart from application of technical knowledge, the committee seems quite susceptible to pressure from outside sources - "'non-combustible' CUs" come to mind. ... and maybe something similar may have happened in relation to 'surge protection'??
Re the OP. He was worried about his expensive equipment being damaged, by surge. Is it snake oil to suggest that fitting an SPD will help mitigate some risk, and therefore , has done the best he can, and gain a bit of peace of mind.
The answers to all that depend upon what one believes, and what 'the truth' (something we may well never know) actually is.

It has always been the case that 'surge protection' might possibly reduce the risk of equipment being damaged/destroyed, but that was equally true in the days when talk of any such devices would routinely described as 'snake oil' (even by some who today 'push' SPDs!).

However, as with every other risk in life, what matters (in deciding whether one wants to try to mitigate the risk) is the magnitude of the risk. We don't, and probably will never, know what that magnitude is, but I would say that it is clearly 'extremely small' - and therefore could be so small that the appropriate response to the OP might actually be (although we could never know this for sure) would to be to reassure him that the risk to his expensive equipment (without SPDs) was so small as to not be worth worrying about - maybe (if we could know) comparing that risk with some other incredibly small one - like 'being struck by lightning'.

In fact, this time in relation to undeniably 'safety-related' issues, it's difficult enough to know/prove whether RCDs have saved a significant number of lives, but most people now regard them as 'very necessary' - so none of this is necessarily all that 'evidence-based'.

Kind Regards, John
 

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