The £1300 AFDD consumer unit

Patents Sparkingchip? There is nothing to patent in any of these items, the designs have been around for far too long. All these things are quite cheap to manufacture as Mike says. Do you have any idea of the cost of the parts of even a high-tech item like the latest iPhone is? Probably about the same as a simple CU retail. The margins on the phones etc. are huge, as you can see from the cash piles of companies like Intel and Apple. I can buy a cheap double glazed window 1m square from a trade supplier for £40-50, not the finest and standard sizes only but I would still expect 50 years life. The Wooden windows in my house were generally fine90 years old, just a huge job to paint, so I had them changed for very expensive Everest ones, which are nothing like as good as they used to be. They have all the features like low emissivity glass and very good locks, Argon in the double glazing etc. but still, the only real change is that they don't need painting!


I suggest that an RCBO cost less than £2 ex. factory (in China), if I buy a sensible quantity perhaps 500k. There is nothing in there which costs very much. An AFDD contains a computer, well in volume these cost 25p! The surge protection VDRs are also cheap, you cannot look at the price of one-off and say it should be half, in volume, it is more like 10% or less.


However, my own objections are largely technical and performance related, as I am sure you will have gathered. If one could say "this device which costs this much, will prevent you from having ANY fires", then I would be on firm ground and the consumer could choose, of course, backed by a guarantee (which would cost little if the performance could be proved). However, we are now in the land of untestable performance and wild claims which can easily be disproved by experiment, and mandates in installation regulations. This is a crazy situation. We have lightning protection which might work, but not if the spike is bigger than a minor disturbance, with a seriously reactive method of earthing, working against a very low impedance source (the mains supply), which means that spike clipping will be marginal at best. In a real installation, it is unlikely that any of these devices could clip an 8/20 spike (the test standard) with a current of a couple of kA and limit the voltage to 4kV, because of the connection inductance and earth resistance. This is a peak power of 8MJ, roughly the same kinetic energy as a car has moving at 100 m/sec stopping dead. Not a lot left of that! Perhaps I am being unfair and these lightning spikes are much smaller and of much less energy, in which case why do I need these devices? The LV directive says that electronics must withstand 4kV low energy spikes, so what am I protecting, perhaps slightly bigger spikes but not much bigger! The incidence of such is not clear or documented, just some arbitrary amount of LV line above ground depending on the area living density. This seems to be aimed at induced current from nearby ground strikes, but have you ever had one near you? Again only high exposed trees usually suffer, and there are few of these in Lincolnshire although there are a lot of overhead lines, so a lot of surge protection.

Patents Sparkingchip? There is nothing to patent in any of these items, the designs have been around for far too long. All these things are quite cheap to manufacture as Mike says. Do you have any idea of the cost of the parts of even a high-tech item like the latest iPhone is? Probably about the same as a simple CU retail. The margins on the phones etc. are huge, as you can see from the cash piles of companies like Intel and Apple. I can buy a cheap double glazed window 1m square from a trade supplier for £40-50, not the finest and standard sizes only but I would still expect 50 years life. The Wooden windows in my house were generally fine90 years old, just a huge job to paint, so I had them changed for very expensive Everest ones, which are nothing like as good as they used to be. They have all the features like low emissivity glass and very good locks, Argon in the double glazing etc. but still, the only real change is that they don't need painting!


I suggest that an RCBO cost less than £2 ex. factory (in China), if I buy a sensible quantity perhaps 500k. There is nothing in there which costs very much. An AFDD contains a computer, well in volume these cost 25p! The surge protection VDRs are also cheap, you cannot look at the price of one-off and say it should be half, in volume, it is more like 10% or less.


However, my own objections are largely technical and performance related, as I am sure you will have gathered. If one could say "this device which costs this much, will prevent you from having ANY fires", then I would be on firm ground and the consumer could choose, of course, backed by a guarantee (which would cost little if the performance could be proved). However, we are now in the land of untestable performance and wild claims which can easily be disproved by experiment, and mandates in installation regulations. This is a crazy situation. We have lightning protection which might work, but not if the spike is bigger than a minor disturbance, with a seriously reactive method of earthing, working against a very low impedance source (the mains supply), which means that spike clipping will be marginal at best. In a real installation, it is unlikely that any of these devices could clip an 8/20 spike (the test standard) with a current of a couple of kA and limit the voltage to 4kV, because of the connection inductance and earth resistance. This is a peak power of 8MJ, roughly the same kinetic energy as a car has moving at 100 m/sec stopping dead. Not a lot left of that! Perhaps I am being unfair and these lightning spikes are much smaller and of much less energy, in which case why do I need these devices? The LV directive says that electronics must withstand 4kV low energy spikes, so what am I protecting, perhaps slightly bigger spikes but not much bigger! The incidence of such is not clear or documented, just some arbitrary amount of LV line above ground depending on the area living density. This seems to be aimed at induced current from nearby ground strikes, but have you ever had one near you? Again only high exposed trees usually suffer, and there are few of these in Lincolnshire although there are a lot of overhead lines, so a lot of surge protection.