OnlyMe wrote: ↑Sun Nov 21, 2021 8:50 am
SPDs are cheap enough to install than perform a made up calculation to satisfy men in suits.
This is why I fitted them, since using FuseBox brand, cheap enough.
IET wbsite wrote:In the previous edition of the IET Wiring Regulations, BS 7671:2008+A3:2015, there was an exception for some domestic dwellings to be excluded from surge protection requirements, for example, if supplied with an underground cable, but this has now been removed and it is now a requirement for all types of premises including single dwelling units. This applies to all new build and properties being rewired.
Seems we have no option with new build.
Neelix wrote: ↑Sat Nov 20, 2021 11:56 am
It’s the cheap sourced LED bulbs which fail …… buy branded and the problems go away
That has not been my experience, I had problems with G9 bulbs
- G9-comp.jpg (46.73 KiB) Viewed 3766 times
it was the cheap one which cured my problems of flicker, i.e. the big one, which breaks all the rules with no watts or lumen marked on bulb.
kellys_eye wrote: ↑Sat Nov 20, 2021 9:06 am
That's why we invented filament bulbs!
That is true, filament bulbs also give off inferred heat so reduce air temperature required to make the room comfortable, so save energy, although not money as electric more expensive than oil or gas. And likely help absorb surges, the same applies to using extra low voltage with a toroidal transformer, the transformer with likely not pass the surge, but could cause a surge, not the case with electronic transformers however.
But the claim seems to be because we use semi-conductors connected direct to mains today, rather than have a transformer first which tended to remove surges, we have more equipment likely to fail because of a surge, (I would have called it a spike rather than surge) and with RCD protection the filters do not connect to earth like they did, so the filters do not protect equipment as well as they did years ago.
Main worry it seems is safety equipment, mains powered smoke detectors for example, seems easy option is use battery powered! But be it the smoke detector, lights, or less important like the TV we clearly don't want to loose them, and with washing machine, freezer, fridge/freezer, TV, etc now being switch mode or inverter powered we have much more equipment both likely to be damaged with a surge, and if damaged likely it put DC on the mains, although the latter really where items generate or have batteries, like solar panels and EV charging.
So we see conflicting reports on if we can use type AC RCD's and need for SPD. Personally I am not sure if we even "Need" a RCD never mind if type AC is good enough, we do see reports like the death of Emma Shaw where we can say a RCD would have saved her, but very few such reports before we had to fit RCD's other than with TT installation, and the loss of a freezer full of food is not funny, more to point is when we don't realise a freezer has part de-frosted, my freezer went bang, so I knew it had failed and when, I had a spare used to brew beer, so turned it on for an hour to cool down before opening the failed freezer door to transfer food, it had clearly failed at end of defrost cycle, so food above the back plate had defrosted, food below plate was OK, but I had thought I had much longer before food defrosted. My new freezers show the highest temperature reached before power returned, but cheaper single phase freezers without inverter drives tend not to have this feature, and once door opened it resets anyway.
So a balance or as we call it today a risk assessment between dangers of having and not having RCD protection. Also financial implications of having or not having or even how many circuits with RCD and SPD use. But in both cases there seems to be a lack and also conflicting data. To the extent of some countries outlawing type AC RCD's.
So we as electricians need to tell the customer you need SPD or RCD or RCBO because other wise this or that may happen, and in real terms we have no idea if this or that can really happen or not. We may watch video by John Ward or Big Clive among others who tell us why, but I watched the John Ward video on type AC and type A RCD's and the way DC was passed through the RCD for test would never happen in real life. Also although we say 40 mS for a RCD to trip, in most cases they trip before we touch anything live, which is likely made live due to water ingress, so even if it took 5 minutes it would still in most cases protect us.
So on RCD's the big question, how many serious injuries or deaths were there in TT installations with type S 100 mA RCD's before the rules asked for 30 mA at 40 mS? Is type A really required? And how much is lost due to surges both before and after SPD were fitted?
If we loose the aerial booster likely it is due to near miss, or a surge, but the SPD in the consumer unit will not stop that, same applies to telecommunication equipment, (phones) they may be damaged, but a SPD in the consumer unit will not help, and since the master socket belongs to OpenReach or Virgin etc, we have no option anyway. Same in a way applies to DNO, if the SPD is with the meter in an outside meter cupboard that is far safer or better place for it to being built into the consumer unit which is normally indoors. So better if built into the smart meter in areas where required, i.e. over head supplies.
But as it stands we as electricians need to tell the customer they need some thing which we are not really sure they need anyway.