[G6ONEDave]

This excerpt is from the IET Code of Practice - In-service inspection and testing of electrical equipment - 5th edition, printed 2020. I am presenting this for safe practice information, as it seems to answer a lot of the questions and comments raised and I hope that it all helps to make a bit more sense of a confusing situation. In fact it has cleared up some of my own questions.

Since 1984, BS1363-1 has required the live and neutral pins on newly manufactured plugs to be sleeved. Plugs manufactured prior to 1984 will have solid pins.

There is no legal requirement to change older plugs with solid pins to ones with sleeved pins; however, the dutyholder should consider whether it is appropriate to continue using a plug of that age, and arrange for them to be changed if necessary.

Note that plugs with solid pins, if removed, should not be re-fitted to any items. In addition, items that are sold or hired must be fitted with a plug that meets the current version of BS 1363-1- in particular, second-hand electrical items sold through a charity shop need to be fitted with a new plug if the existing plug has solid pins.

Non-rewirable plugs fitted to Class 2 double insulated items may be manufactured with a non-conducting (usually plastic) pin, which is provided solely for the purposes of opening the socket outlet shutters and confirming polarity. These are often found on small power supply units or phone chargers, which are marked with the double insulation symbol.

Some manufacturers use metal for the earth pin even when not required, as this usually has better physical strength. If a rewirable plug is used (even on a Class 2 item), it should always have a solid metal earth pin.

Dave