ARE WE THE MEAT IN THE SANDWICH?

I don't disagree!


Also add in CU manufacturers not making fit-for-(UK)-purpose terminals and plastic enclosures that are truly flame retardant.


   - Andy.

Don't get me started. 


Add in the new RCDs because of appliances stuffing DC onto circuits and TTing electric car chargers as the cars are not double insulated.


A very old grumpy, cynical old fart who is pleased to have retired.

My understanding is that end-user equipment is supposed to be able to handle transients up to 1.5kV,  while the fixed wiring is supposed to be able to handle up to 4kV (and the meter + cut out 6kV). So it's the job of the fixed wiring to reduce transients from 4kV to 1.5kV before it reaches the equipment. It seems reasonable to me that, in areas prone to transients, you spend £100 on an SPD at the CU to achieve this rather than have to engineer every little GU10 LED lamp, phone + USB charger etc to handle 4kV rather than 1.5kV.

How many of your customers have had equipment wiped out by transients?


Millions of consumers buy surge protected extension leads, but how many  have asked surge protection as part of their fixed installation.


Again all the manufacturers advertise them to electricians in anticipation of the electricians selling them to the end users, instead of actually targeting the end users so they are asking the electricians to fit them. 


All the supposed improvements to consumer units and protective devices end up having to be a hard sell by the electricians, because there is no customer awareness of what is recommended or required by the regulations, so no customer demand.


Andy Betteridge

The purpose of regulations and standards is not to sell new products to customers, by forcing new products which they do not need onto them. That is exactly what is happening with surge protection and AFDDs. It happened with PME too, because it was supposedly cheaper and the saving would be given to the customer. Now the poor network condition is being used to force the customer to take precautions because of the network problems.


The problem we are having is very simple: All these "nice to have" products are put into BS7671 as requirements, and due to other factors we must implement then in all new installations whether the customer wants or can afford them or not. A secondary problem is that the prices being charged are simply rip-off, an AFDD probably costs a few quid to manufacture (and sells relatively reasonably in the USA, say £20) yet here is ten times the price. It may be claimed that this is development cost, but very little is required to simply reproduce the American product, and there is little reason to start from square one anyway. The same applies to surge protectors, they are simple, have been available in all sizes for a long time, and are overpriced and not designed to fail cleanly so need external bits and pieces.


The next point is that neither of these products has any pedigree, although AFDDs have been in the USA "Code" for at least 10 years. Our own tests show that AFDDs are not good at detecting ANY known real faults, although they can be induced to trip with a test jig which has little comparison to reality. To get an arc, a material (Carbon) which we do not use in installations has to be used as one of the electrodes, as otherwise, it is virtually impossible to strike an arc between copper electrodes. The second point is that an AFDD does nothing with an RCD protected T&E cable because any fault will trip the RCD long before the AFDD, and domestics have RCDs everywhere! I have covered surge protection elsewhere, the susceptibility of electronics is basically bad design, good electronics is very robust indeed.


Overall it is doubtful that we need either of these products, in a free market they would fail very quickly.

I have actually considered installing a SPD at home, though only because I need to do a “bit of tidying up” at the intake, the hob, oven and cooker switch socket are still not RCD protected being separate connected separately from the CU with a fused switch at the intake. So if I stick another small CU in it could easily have an SPD in it. But I will almost certainly skip installing AFDD protection to this circuit. I am assuming a SPD would last a lifetime in my home as I doubt it will ever see active duty.


Assuming Boris can actually do a wonderful trade deal with the USA, is it actually a possibility that American manufacturers will re-engineer their AFDD to produce UK style consumer units and come in undercutting the manufacturers currently supplying the UK market devastating their businesses?


Andy Betteridge

Bearing in mind BG SPD are now £22.

Not a type 1 there Andy?

To Burn

It is likely that both of these were broken neutral events. You should contact the DNO with this accusation and see what they say. Surges do not damage either of these well protected components in my experience, and that cannot be a coincidence that they followed DNO "outages", because just switching on or off damages nothing! If you don't complain they will just keep it quiet. Broken neutrals are notifiable events, but often this doesn't happen. I will be very interested to follow up their reply.


Regards

David CEng etc.