In that case, somewhat of a red herring in relation to this discussion about SPDs - which, if they are useful needed at all, can obviously only deal with mains-borne spikes/surges!
Kind Regards, John
What will happen if my SPD activates?
- Thread starter Vicario
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Kind Regards, John
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The answer will presumably be 'no', since only a pretty (probably very) small proportion of domestic installations currently have SPDs. However, that wouldn't help us to know whether SPDs might reduce the failure rate of LEDs. I have seen no information about that, but I suspect that SPDs might well not make much, if any, difference.
There is an awful lot of misunderstanding about quoted 'life expectations' of products (be trey '\LEDs' or anything else, which leads to unrealistic expectations. The life expectancies quoted are invariably medians. Hence if, for an LED, it is, say, 10,000 hours, that means that half of the LEDs are expected to last for at least 10,000h, but it tells us absolutely nothing about how early failure is likely to occur in the half which do not make 10,000 h.
Most manufactured products have a 'bathtub'-shaped survival curve, with a high rate of early failures, followed by a long period with very few failures until, eventually, failure rate starts to climb. That means that many of those LEDs which do not reach 10,000h my well fail very early - maybe within hours (sometimes minutes, or even seconds!) or hundreds of hours. Hence, it could be that, despite a (median) life expectancy of 10,000 h, there is actually nearly a 50% change of a very early failure. If people understood that, we would perhaps hear a lot less about 'unexpected' LED failures!
Kind Regards, John
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Yes I have done Mean, Median and Mode. And LED bulb design does vary manufacturer to manufacturer, unfortunately price seems to have very little impact on quality, I have shown this
of G9 bulbs many times, the larger one was also cheapest, and did not comply with UK regulations, but worked far better to smaller one, but the big change is I use to buy a pack of bulbs for a pound or two, now one bulb can cost £5 or more, and where one has a chandelier or silly down lights one room may have upwards of 8 bulbs.
In the old days of tungsten I kept a draw or cupboard full of bulbs and swapped as required, I would say an average of a bulb every other week, but had less bulbs, now an average of a bulb a year. Even the rarely used bulbs which are still tungsten seem to last longer.
Then I walk into my old house now my sons, and see 10 failed bulbs, he blames cheap toolstation bulbs, but I don't use expensive bulbs, in fact the one time I bought expensive Philips CFL golf ball 8 watt bulbs their life was very short, and 16 of them so not one odd poor one.
Seems more likely simply unlucky and a bad batch. But same house where a batch of Philips bulbs failed to a batch of toolstation bulbs failed, with no SPD, and same house where the RCD would trip in a thunder storm, no over head cables in the street, but clearly thunder storms do affect the supply.
Not convinced a SPD will help, but also not convinced a SPD will not help. I have fusebox consumer unit, when I bought it a few years ago the SPD was two module wide with no overload, today one module wide with overload
what is going on?
Nominal Discharge Current (In 8/20us) 20kA
Maximum Discharge Current (Imax 8/20us)40kA
Both types.
The video linked in previous post does talk about this, and also the types of SPD, both say T2 as said at around £30, BG and Fusebox, I fitted one, seemed worth the money to save LED's even if not sure they work. But for Wylex nearly £90 and one has to ask what is the difference?
I note this IET resource shows a Wylex CU with double width SPD and no MCB. different make, but looks like my own CU.
of G9 bulbs many times, the larger one was also cheapest, and did not comply with UK regulations, but worked far better to smaller one, but the big change is I use to buy a pack of bulbs for a pound or two, now one bulb can cost £5 or more, and where one has a chandelier or silly down lights one room may have upwards of 8 bulbs.In the old days of tungsten I kept a draw or cupboard full of bulbs and swapped as required, I would say an average of a bulb every other week, but had less bulbs, now an average of a bulb a year. Even the rarely used bulbs which are still tungsten seem to last longer.
Then I walk into my old house now my sons, and see 10 failed bulbs, he blames cheap toolstation bulbs, but I don't use expensive bulbs, in fact the one time I bought expensive Philips CFL golf ball 8 watt bulbs their life was very short, and 16 of them so not one odd poor one.
Seems more likely simply unlucky and a bad batch. But same house where a batch of Philips bulbs failed to a batch of toolstation bulbs failed, with no SPD, and same house where the RCD would trip in a thunder storm, no over head cables in the street, but clearly thunder storms do affect the supply.
Not convinced a SPD will help, but also not convinced a SPD will not help. I have fusebox consumer unit, when I bought it a few years ago the SPD was two module wide with no overload, today one module wide with overload
what is going on?Nominal Discharge Current (In 8/20us) 20kA
Maximum Discharge Current (Imax 8/20us)40kA
Both types.
The video linked in previous post does talk about this, and also the types of SPD, both say T2 as said at around £30, BG and Fusebox, I fitted one, seemed worth the money to save LED's even if not sure they work. But for Wylex nearly £90 and one has to ask what is the difference?
IET said:
I note this IET resource shows a Wylex CU with double width SPD and no MCB. different make, but looks like my own CU.
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No, I haven't watched it and will not bother. A certain proportion of LED lamps will fail early, so I would not attribute the failures to surges - there can be many other reasons for failures too, including improper mounting, in fittings designed for other lamp types with heat build up.
I have mostly LED lighting here where lamps are regularly used, no failures except one, which has twice failed. That a lantern style fitting lighting up my drive, on from dusk to 11pm, where the 8w LED lamps tended to last 12 to 24 months before failure - around 1000/2000 hours. I didn't immediately suspect heat as being the cause, but the fitting had no ventilation at all. When I last replaced the lamp, a few years ago now, I added a tiny amount of ventilation. Early days, but so far it has run for 36 months reliably.
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Yes, I appreciate that - my point was that many/most damage to electronics is via other than mains bourn spikes.
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If 2 or more items fail together, then likely a surge. But one item who knows.
note 'was', so it seems we have no option, same as RCD. But I can't see a down side with SPD, there are clearly problems with RCD's, I know in my old house the RCD would have a bout of tripping. This house all RCBO's.
Fair enough. In that case, you should understand, better than most people (who do not seem to understand this), that, as I said, to half half of a batcxh of LEDs fail duering the first few hours (or first few dozens of hours is not in any way incompatible with a (true) "average (median) life expectancy" of 10,000 hours (or whatever).
Same here. I have a very large number of bulbs in my house (many 3-bulb and 5-bulb fittings) and, in the past, used to buy incandescent bulbs (mainly 25W candle and 40W golf ball) literally in batches of at least 20-30, since I was having to replace at least one a week on average. Now, with LEDs, it is very rare that I have to replace even one.
... but, as you go on to say, perhaps "one odd poor batch". However, although I don't know if there is any truth to this, I have heard it said that golf ball LEDs more than about 5W (of any make or cost) are notorious for failing very early, probably because the very limited amount of space available for the electronics leads to over-heating problems.
As I've said, same here - and I therefore remain very uncertain about anyone who asserts a definite 'need' for them.
Kind Regards, John
Having tested about 1300 one Watt LED golf ball lamps and finding about 100 with failures (*) I will confirm they are notorious for failing.
(*) Some others had obvious signs of electronics damaged by ingress of moisture.
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Fair enough, but I'm not sure what that 'confirms' in relation to my comment (which you quoted) about...
Kind Regards, John
I think Bernard was trying to point out that many of these LED's are faulty out of the box and some (in common with most electronics) fail soon after being put into service. If they survive the first few weeks, likely they will have a long service life - failures nowt much to do with surges on the power.
That was the very point I made recently, together with pointing out that a high rate of very early failures was in no way compatible with an 'average' (median) life expectancy of 10,000 hours, 20,000 hours or whatever. - so bernard's post would have made total sense had he quoted my post in which I had said that very thing,
However, in his recent e-mail, what bernard did quote was my comment about a possible particular problem which may exist in relation to "golf ball LEDs more than about 5W" - and responded by telling us of his experience with 1W LEDs
Kind Regards, John
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