Internal wiring of USA v UK mains plug

Are you sure about that? There were several different socket outlets still in use - 3, 5 and 15 amp all in either two or three pin. As well as some odd types as an alternative to the common 13 amp plug - notably D&S and Walsall gauge, sometimes used in council housing estates. But I think the voltage was standardised some time before then.

Yes the requirement for a fitted 13 amp plug hasn't always been.

Heh heh - in the UK the bayonet fitting is the common one for GS bulbs.

Perhaps the majority of the sort of things you'd want to plug in to that are now double insulated so require no earth.

--
*A dog's not just for Christmas, it's alright on a Friday night too*

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

Eh? Even with final circuit rings there were at least three types of sockets. Normal, D&S (round pins where the live was a removable fuse) and Walsall gauge. Same as 13 amp but the pins at 90 degrees. The last two often used by councils on housing estates. Gawd knows why. Some official with a bee in his bonnet. Or saving pennies.

Then plenty of the old types still in use. 3,5 and 15 amp round pin. In both 2 and three pin. Then there were some oddities with flat pins.

US visitors used to laugh at our variety of sockets, domestically. Now we have only one, and they have the variety...

--
*The only difference between a rut and a grave is the depth.

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

2, 5 and 15A and they were all part of a single standard. Only the 2 and 5A existed as 2 pin types.

Graham

The 2 and 3 pin 2, 5 and 15A plugs were all part of a single standard.

Never seen any flat pin jobbies.

As for Walsall gauge I've only ever seen that in the tube. Did councils really fit them ?

Graham

Exactly that. The precise term is "Knob and Tube", The insulation is a mixture of silk, rubber and asphaltic tar that remains quite stable under most conditions, although it becomes brittle at temperature extremes (hot and cold). One would think from the ingredients that the insulation would burn from a sideways glance... not so at all.

I worked my way through college as an old-house electrician and ran across scads of the stuff. Some of the original lighting circuits (but nothing else) in our house are still operating from K&T wiring installed in 1906. The house was built in 1890, originally piped with gas for lighting.

Will show you it in-situ.

If you keep in mind that the conductors are typically separated by some distance, and where they penetrate boxes, walls and turn corners, there is either a ceramic insulator (knob) or ceramic/ additional woven silk/asphalt/rubber (tube), as long as the copper itself is not raised to ignition-point temperatures it is quite safe.

With reference to the NEC, it may be maintained but not installed-as- new.

And an unbelievable amount of flea-market wind-chimes are made from old ceramic tubes....

Peter Wieck Wyncote, PA

Not so. My parent's house had 2 pin 15 amp sockets - one in each room, as installed when the house was built.

--
*I just got lost in thought. It was unfamiliar territory*

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

I'm just guessing but I'd say the BS that applies to them now didn't when they were first introduced.

--
*No word in the English language rhymes with month, orange, silver,purple

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

A lot. Trust me on this.

David Starr

This is only confusing things. There are other types as well, but the ones that dont fit UK sockets are todays EU ones. The old ones I refer to are not the old british 2 pin plugs from the 1920s, but the old french ones that were still in use in many places in fr in the 80s.

There's more than one type answering that description, so its hard to know what you mean.

Most work that way. There are also some with a shutter operated by the L&N pins. These are harder to defeat. Not sure but I think MK introduced those.

The main purpose of the shutter is to stop toddlers poking things in. They also discourage people from sticking bare wires in, followed by a plug on top. This bad practice is a lot less common today as it doesnt usually work with insulated pins, plus ever increasing material wealth makes it a pretty much obsolete practice even in dodgy circles.

NT

Seems the US developed a long lasting wiring system long before we did. It wasnt until ashathene and pvc cables in the 60s that we finally got cables of types that would truly last long term. So old wiring here is almost invariably highly risky, in a very bad way and only very occasionally encountered at all.

The main old types here are

- cotton/rubber, and its normal for the insulation to have perished and fallen off in places, and not just at the ends.

- lead sheathed rubber insulated from 1930s, the ends of which get into a state.

NT

When was this built ?

Graham

Since a 16A fuse for a UK plug doesn't even exist, I'll take your " Trust me on this." with a pinch of salt.

Graham

There is no such thing as an *EU* plug.

Thankfully it's one thing they haven't tried to standardise.

Graham

Just wait, I'm sure they'll get around to it sooner or later...

I dont see how. Cooking fire risks certainly differ by socio-economic group, but I dont think electrical fire risks vary much. Things are perhaps different in the US.

20mA is the typical figure for our standard 30mA RCDs, but most fire causing faults are not detected by RCD, and most properties dont have an RCD.

But that is a separate issue to fault current discriminaiton.

NT

That is just the half-of-it. We have had NEMA (National Electrical Manufacturers Association) standards for pretty much all of present living memory such that appliances (AC & AC/DC) manufactured in the

20s are compatible with receptacles and ratings today. For instance, 1920s-installed duplex receptacles will accept fat-blade neutral (polarized) plugs that are today's standard. One can 'call out' by NEMA number a receptacle and plug that are specific to, and compatible with both the load and application, from isolated-ground hospital- applications to heavy-load vibration-proof applications, one, two (yes, there is still 4-wire/2-phase power applications in the US) and three-phase. And, be assured that that unit and/or combination will fit and be acceptable anywhere in the US. One example I claim is a 1928-model Sky Rover radio with a tri-voltage switchable power-supply (105/110/120V) and a standard NEMA-labeled plug. About a year-and-some after NEMA's inception.

On a related note, IMAGINE purchasing an appliance with no plug on it... on the premise that what is in your house is not the same as next door, or next door to that. AND THEN... the home-owner is expected to purchase said plug compatible with their specific system, THEN to install it correctly. This was the common state of affairs in parts of Europe until not so long ago.

Fascinating also that every country in Europe seems to have a different standard for receptacles, wiring, fusing and so forth. Y'all do need standards if only to allow cross-border commerce much less reduce costs and enhance safety.

Peter Wieck Wyncote, PA

Actually, this is common in USA woodworking equipment also. Many of my 240V machines came with no plug.

With no plug, or no cord at all? Those are two entirely different things. The former is illegal, the latter quite common. With the latter, there will be a note: Professional Installation Only or words to that effect.

Peter Wieck Wyncote, PA

I've seen both "cord with no plug" and "no cord at all". The reason is usually that the tool can be internally wired for either 120v or

240v, and which you choose determines which plug you must install.

I'm not talking about hand tools, I'm talking about big cast iron tools like table saws and jointers.