I think we all know Part P is referring to a distribution unit, however we are talking about definitions, where a installation is in the control of an ordinary person type tested units should be used. However I am sure there are many cases where they are not used. I have every intention to use an old consumer unit to fit some sonoff units into to work some of my lights, since I am not an ordinary person they is no rule to say I can't, and since it is not being used as recommended by manufacturer it is not a consumer unit, it is simply an adaptable box. It is not even a distribution board.
I thought for years the L on a plug meant live, but seems all those years I had been getting it wrong it means Line. As to 110 volt plugs with L and N marked on them, seems really an odd marking, what does N mean? It is line two, there is no neutral on a 110 volt system, we would not use the yellow plugs for any other voltage, same with the cable we know it should be green/yellow, brown and black, try buying any, the outer is yellow so clearly for 110 volt but it has a blue coloured core.
We all ignore it, we know it's wrong, but who cares? We all know 110 volt site power is either 55-0-55 or 63-0-63 depending if from split phase or three phase, if the colours are wrong it really does not matter, or does it, if the colour does not matter there then does over sleeving a blue wire to a light switch matter?
It only really matters when an ordinary person is involved.
So we have adopted a name, transformer, they in the main transform either between voltages or currents, but then we have an odd one out, the isolation transformer which does not transform anything all it does is isolate, we know it should not really be called a transformer but it is made the same way as others so we retain the same name.
This has been done again and again, and in the main we have some way to differentiate when we use some new device to replace the old, so where a simple wire wound 50 Hz transformer is replaced with a high frequency transformer and other devices to turn the 50 Hz to high frequency we add a word, we call it an electronic transformer, that's OK, name does not matter as long as we know what it is.
However the ballast and driver are not so easy. We don't say voltage or current in front of word driver we don't even say AC or DC, I worked on aircraft ground lights and understand the whole idea of a current to voltage driver so all lights are the same brightness, current control was always called drivers, now we have units which control voltage called drivers, and no one can tell you what your going to get when you order a driver unless you read the spec.
We by a LED tube, and it says with magnetic ballast simply replace the starter with the new one provided. But how does the ordinary person know if it's a magnetic ballast? OK we know, but there is nothing on the fluorescent fitting that can be read without using a tool to say if fitted with a magnetic or electronic ballast. And often the replacement starter is a fuse, but no label saying fuse, and even the marks that are on them rub off, so very easy to get a fuse and starter mixed up.
It is hard enough for people in the trade, but these definitions must be very confusing to ordinary people. I remember ordering a head lamp, I had been told bulbs grow in the garden, I got a head lamp, minus the bulb, so we look to history, and we had a spigot onto which the lamp fitted, and inside the lamp with has a wick, mantle or bulb depending if oil, gas or electric, so I now always call them bulbs or tubes. Even a cob which is not bulbous I still call it a bulb.
I remember working in Algeria with a fleet of Chev's, trying to work out what a track rod is called in USA was a problem (push pull bar) so we want standard international names. In Algeria we had to have lights on the side of wagons, we called them flur de gabre may be spelt wrong, now used in UK, I have not a clue what they are called, only know the French name.
What I am saying names and definitions matter, we all need to be singing from same song sheet, and when some one asks for a MR16 we need to know what that means, so we can then ask what type of MR16 and not give them some random unit which may or may not work.
We consume electricity in our houses so little matters in terms of what they actually look like they need to contain certain things and meet certain aspects of the building regs - metal and safety aspects etc
