I see your points Graham, but I think you are being misguided as to the possible levels of risk. Whilst Appendix 15 does suggest a degree of care is required it is NOT a regulation and is not usually up to the electrician anyway. From your comments, I would infer that you think that double sockets should not be permitted, or possibly they should only be fed via a 13A FCU. You also imply the 2.5mm cable size is inadequate, whereas I suggest that it is not, and is proven by 10s of millions of installations that it is perfectly satisfactory.

I also see that your comment about a washing machine and tumble drier is generally factually incorrect, in that the washing machine heat time is severely limited to perhaps 10 or 15 minutes. This is essentially contrary to Fig 15A (ii) because the load profile is not a “space heating type profile" which may be continuous for many hours. It is necessary to understand that the power dissipation in a length of 2.5mm cable is 18 Watts per metre at 32 Amps, and the heat loss by convection is approximately this at 20C ambient. The heating time is therefore very considerable to get to 70C, more than 15 minutes or so, and if it gets to 71C does this actually matter?

I mentioned soldering irons because you suggested that a socket at a temperature similar (enough to go black) to an iron (300 C) is contrary to the EAWR, and therefore an electric soldering iron is similarly so. I realise that the situations are slightly different, but both require a similar level of care from an employee. The center of the point is that sockets do not normally burn up when loaded to 13 or even 20A (about the fuse blowing fairly quickly current). Only poor or faulty sockets might blacken, or ones mated with a poor plug. It is not reasonable to suggest that this is normal, or similarly, certain FSUs on immersion heaters sometimes suffer in the same way, usually due to poor fuse contact should not be used. Good ones do not suffer in this way.

Ultimately this discussion about ring circuits (again) is not reflective of real installations. There are bound to be a few problems, and maintenance is obviously required. However, realistically it is impossible to prevent any faults with anything. If you apply the same standard of zero faults, garages would endlessly be in court. Cars are quite reliable now, much better than 40 years ago, but there are still not zero problems and such is impossible. Poor quality products should be eliminated, but in the bigger picture that is not controlled by a standard. Standards rarely say anything about reliability, and this is always designed in, not tested in, and not under external event controls.  We might think that we can control usage, but we cannot. We also should not attempt to make things completely “idiot-proof”, it is an ideal that cannot be achieved. Fixed wiring systems are extremely reliable, even with fairly extreme abuse.  Remembering the loose tails fiasco, it could have been foreseen by a reasonable person, and the “controls” on meter installers make a problem inevitable. Double sockets are occasionally problematic, but it is easily detected and corrected with a new socket. Faults and improper usage are much more common with appliances, tumble driers where the filters are not cleaned are a case in point.

I suggest that a single socket and a two-way adaptor is much worse than a double socket, but that would be the result of removing double sockets!

I see your points Graham, but I think you are being misguided as to the possible levels of risk. Whilst Appendix 15 does suggest a degree of care is required it is NOT a regulation and is not usually up to the electrician anyway. From your comments, I would infer that you think that double sockets should not be permitted, or possibly they should only be fed via a 13A FCU. You also imply the 2.5mm cable size is inadequate, whereas I suggest that it is not, and is proven by 10s of millions of installations that it is perfectly satisfactory.

I also see that your comment about a washing machine and tumble drier is generally factually incorrect, in that the washing machine heat time is severely limited to perhaps 10 or 15 minutes. This is essentially contrary to Fig 15A (ii) because the load profile is not a “space heating type profile" which may be continuous for many hours. It is necessary to understand that the power dissipation in a length of 2.5mm cable is 18 Watts per metre at 32 Amps, and the heat loss by convection is approximately this at 20C ambient. The heating time is therefore very considerable to get to 70C, more than 15 minutes or so, and if it gets to 71C does this actually matter?

I mentioned soldering irons because you suggested that a socket at a temperature similar (enough to go black) to an iron (300 C) is contrary to the EAWR, and therefore an electric soldering iron is similarly so. I realise that the situations are slightly different, but both require a similar level of care from an employee. The center of the point is that sockets do not normally burn up when loaded to 13 or even 20A (about the fuse blowing fairly quickly current). Only poor or faulty sockets might blacken, or ones mated with a poor plug. It is not reasonable to suggest that this is normal, or similarly, certain FSUs on immersion heaters sometimes suffer in the same way, usually due to poor fuse contact should not be used. Good ones do not suffer in this way.

Ultimately this discussion about ring circuits (again) is not reflective of real installations. There are bound to be a few problems, and maintenance is obviously required. However, realistically it is impossible to prevent any faults with anything. If you apply the same standard of zero faults, garages would endlessly be in court. Cars are quite reliable now, much better than 40 years ago, but there are still not zero problems and such is impossible. Poor quality products should be eliminated, but in the bigger picture that is not controlled by a standard. Standards rarely say anything about reliability, and this is always designed in, not tested in, and not under external event controls.  We might think that we can control usage, but we cannot. We also should not attempt to make things completely “idiot-proof”, it is an ideal that cannot be achieved. Fixed wiring systems are extremely reliable, even with fairly extreme abuse.  Remembering the loose tails fiasco, it could have been foreseen by a reasonable person, and the “controls” on meter installers make a problem inevitable. Double sockets are occasionally problematic, but it is easily detected and corrected with a new socket. Faults and improper usage are much more common with appliances, tumble driers where the filters are not cleaned are a case in point.

I suggest that a single socket and a two-way adaptor is much worse than a double socket, but that would be the result of removing double sockets!