In my travels around, I’ve seen many a variety of plugs and sockets and have often mused on which ones are the best on the grounds of safety, neatness and convenience. I’ll stick with the world of 230V phase to ground here as the parallel blade/round ground North American standard seems to be widely used in the 115V world – please correct me if I am wrong. I have personally experienced (held, inserted and often dismantled/wired) the following and have noted their quirks and foibles. UK fused 13A square pin, UK 15A, 5A, 2A round pins, Euro plugs both French and rest-of-Europe types, Australian/New Zealand incline blade 10A, Argentinean modification of the aforementioned and a Chilean in-line three pin. In addition to these are various two round pin plugs of many diameters and spacings as well as the extensive varieties of NEMA types used in North America.
A lot of these have many things in common but there are major differences and contradictions. In general a global standard that I dare suggest at the end would incorporate all of the following features which are not all possessed in any of the systems above.
First of all it has to be as safe as reasonably possible with built in features to prevent accidental contact with the energized connectors or sockets, i.e. some form of shuttering on the socket and shielding on the pins of the plug. A good example of this is the UK 13A square (OK it’s oblong!) pin plug system with ground pin releasing the shutters on the phase and neutral and plastic sheathing on the energized pins adjacent to the plug body.
The plug must fit snugly and positively into the socket without all that limp flapping around that one can get with NEMA style parallel blade type, especially the ungrounded ones.
Likewise it should be robust. This pins or blades should not readily bend or break like the NEMA ones often do. The Ozi/NZ blades don’t readily bend.
It must be compact. Both the UK (new and old) and the Euro Plugs are bulky. The UK 13A is sized to contain an internal fuse but that is only to provide protection to the appliance cord on a 30A fused ring main. I used, as a Brit, to think this type of system was state-of-the-art until PaulUK showed me the error of my ways. The ring main should be dispensed of and this new unfused plug and socket system would not be allowed on it – radial branch circuits only like the rest of the world.
The system must incorporate a non-bypassable grounding (earthing) system but would not require a ground pin on ungrounded equipment. This has impact on its compactness and further rules out the UK system of using a ground pin (even a plastic one!) to move shutters and ensure polarization. It likewise rules out the French Euro plugs which rely on a grounding pin, contained in the socket, to force polarity. I’ll enter the orientation debate here and state that the system should have the grounding (earthing) conductor at the top. In my mind the weight of argument (which occasionally rages freely on the General Section) favours this orientation. IMHO the common North American and Antipodean sockets are upside down!
The system must be polarized! This rules out the non-French Euro plug and any system that uses symmetrical phase and neutral pins on ungrounded plugs. The North Americans very early got round to making one blade wider than the other to ensure polarity where required on ungrounded plugs and is almost a standard on 115V systems. Of course, their 230V 15A plugs don’t need to be polarized as that comprises an Edison circuit with twin phases. In my mind, the cleverest system is the Australian/New Zealand standard that uses non parallel blades. Polarity must be global and a situation like Argentina which uses Ozi/NZ plugs with reverse polarity must be avoided at all cost.
It should be standard that the phase connector in a socket is switched so that the plug does not have to be removed or inserted under load.
The system must use plugs whose pins are at a right-angles to the cord. This applies likewise to any socket face on an extension cord. Plugs with pins parallel to the cord cause the cable to stick out of the socket which takes up more room on a work surface - they are liable to get snagged, tugged and look just pain ugly. The orientation of the socket and plug should be such that the cord goes straight down the wall – UK influence speaking here! This will have implications for duplex sockets – this useful configuration will require them to be mounted besides each other rather that above each other as in North America so that the cords do not interfere with the other socket. Another reason for having right-angle plugs is that they cannot easily be pulled out of the socket by the cord (either by accident or design) and a right-angled socket on an extension cord makes it less likely to part company with its plug when the lot is dragged along the ground – the resultant extended cable ends up more or less straight.
Finally the plugs must be rated sufficient for my 3kW hot water kettle and those 10A ones found in Oz/NZ are just not rated high enough!
So what does my proposed international system look like? It is based strongly on the self-polarizing Australia/New Zealand standard (non-parallel blades) but with the grounding (earthing) blade up, and with switched duplex sockets mounted side by side. The plugs would be rated to at least 13A and have the out-sides of the energized blades partially sheathed to prevent accidental contact on insertion or removal. A shuttering system would make it difficult for anyone to insert a foreign object into the socket and yet would not require a grounding blade to open them – equal pressure system maybe. Only right angle plugs with the cord emerging opposite the grounding pin side would be allowed on both two and three pin varieties. Unless the fuse was very small, they would not be fused and therefore not fitted on ring-main systems.
Pulls on steel helmet …
Oh, and just before I retire to my fox-hole, this new standard may eventually be used in new North American domestic installations which use 230V phase to ground (putting grunt into the average American home) and introducing the bayonet cap light bulb for the high voltage lighting. A new world standard! We’ll work on that frequency issue next.
Dives for cover …….