RS Components order FAIL / UK plug discussion

[DavidJRobertson]

Which are?

On wire breaks in the system and 1 wire has to carry all that current, which since you use smaller wires it can't handle etc etc

What you're really saying is:
our system - one wire breaks, reduced current carrying capacity
your system - one wire breaks, the whole thing stops working

So basically ours is partially redundant, although could have safety issues should one wire break and a particularly high current is drawn.

I'd rather not have any current then not know there is a problem and possibly burn down the house.
At least with no power I know something is wrong.

Fair point.

[chrome]

Things don't break without people tampering with them.

Yes you are correct, things never break without human intervention.

[G7PSK]

Most rings will be 2.5mm sq. this is rated at 26 amps clipped, on a cable tray, bunched and unenclosed that means virtually all situations with house wiring in the UK so a ring will carry 52 amps and is normally tripped for 32 amp longer rings will be wired with 4mm sq or 6mm sq rated at 38 and 49 amp giving 76 and 98 amps respectively so if a break in one wire should occur there is usually an ample safety margin.   

[tom66]

The ring main was originally implemented after WWII when copper was in short supply. It has stayed with us for nearly 70 years and shows no signs of going away. Nowadays in my experience most sides are wired with 32A wire so there is ample safety margin if one leg fails.

[Monkeh]

Nowadays in my experience most sides are wired with 32A wire so there is ample safety margin if one leg fails.

There is no such thing as '32A wire' and no, that is not common practice.

[tom66]

Nowadays in my experience most sides are wired with 32A wire so there is ample safety margin if one leg fails.

There is no such thing as '32A wire' and no, that is not common practice.

I may be referring (inadvertently) to twin-and-earth wire, which is typically rated to around 25 amps. I don't know where I got 32 amps from, possibly confusing it with something else.

[Monkeh]

Nowadays in my experience most sides are wired with 32A wire so there is ample safety margin if one leg fails.

There is no such thing as '32A wire' and no, that is not common practice.

I may be referring (inadvertently) to twin-and-earth wire, which is typically rated to around 25 amps. I don't know where I got 32 amps from, possibly confusing it with something else.

T&E is a type, not a size. Standard sizes of it are 1.0mm², 1.5mm², 2.5mm², 4mm², 6mm², 10mm², and 16mm². Rating is dependent on installation method, and there are other factors in determining cable type and CSA.

[vk6zgo]

Australian plugs do just about all the things which are quoted as desirable,plus they are simple & robust.
Plug fuses as per the British system are only necessary with the ring main system & add extra complexity.
Australian power outlets (GPOs) use double pole switches.
Our plugs are equally nasty to step on with bare feet,as they seem to swing up & dig into the foot,

[Monkeh]

Yes, the Aussie plugs are good. That's our influence, you understand.

[HackedFridgeMagnet]

Actually the Aussie plugs are originally American, but they didn't catch on in USA.

[T4P]

Well i have the same plugs here ... a "steamboat" blew a hole in the fuse and the breaker didn't trip ... then again ring mains
BUT i had situations of fuses not blowing before the Circuit breaker
But the safest part is that every EVERY socket has it's own switch so it's ... safe.

[vk6zgo]

Actually the Aussie plugs are originally American, but they didn't catch on in USA.

They are very similar to an old US type,but the Australian specification was written locally.
One of the Chinese standards is also very similar,except that they put the earth uppermost,which is a better idea.
The simplicity of the design allowed Australian manufacturers to embrace modern materials,whereas the complexity of other designs kept manufacturers using bakelite & similar materials until strength & rigidity problems of the newer plastics were resolved.

[Bored@Work]

Oh, and by the way, Britain, including Scotland, is in Europe ...

I would never have guessed ...

See, you learned something new. Now go out of the house and welcome Europe.

[G7PSK]

Nowadays in my experience most sides are wired with 32A wire so there is ample safety margin if one leg fails.

There is no such thing as '32A wire' and no, that is not common practice.

Wire goes by size in sq mm. the amp rating varies according to how it is installed laying on the rafters or clipping to a wall allows for a higher current than total enclosure in a conduit with other wires tightly packed around it. According to my chart which I have in front of me, 2.5mm t&e can vary between 18 and 29 amps and 4mm 27 to49 amp. The 32 amps is the usual rating of the ring's mcb.

[T4P]

What they do with the ring mains here in my town is use 2x2.5mm ... for 32amps

[G7PSK]

Why not just use 4mm or 6mm.

[buxtronix]

Other features of UK plugs which seems to have been missed here...

The earth pin is always on top (the L/N are "down" when facing the socket) and is exposed all the way to the plug body (not partially insulated). With the earth on top, anything that happens to fall down onto a partially withdrawn plug and into the gap is likely to sit in contact with the earth pin rather than a live one.
Particularly important with metal window blinds falling onto a power point...most other designs risk the blind being made live.

Another feature - the cable always goes in at 90 degrees, never straight. This prevents things like furniture pressed against the wall from straining the cable and potentially splitting the insulation. It also discourages pulling the plug out by the cord (which introduces a risk of pulling the wire out of the plug with habitual pulling).

What else...ah yes, the flat pins offer greater contact area with the socket electrics, increasing current carrying capacity - the round continental plugs dont allow for much practical contact area, making things hotter.

Brilliantly engineered, though from a users point of view, big and unwieldy!

[Monkeh]

Nowadays in my experience most sides are wired with 32A wire so there is ample safety margin if one leg fails.

There is no such thing as '32A wire' and no, that is not common practice.

Wire goes by size in sq mm. the amp rating varies according to how it is installed laying on the rafters or clipping to a wall allows for a higher current than total enclosure in a conduit with other wires tightly packed around it. According to my chart which I have in front of me, 2.5mm t&e can vary between 18 and 29 amps and 4mm 27 to49 amp. The 32 amps is the usual rating of the ring's mcb.

Well aware.

Why not just use 4mm or 6mm.

Defeats the purpose. And you try getting 6mm² into most sockets twice. May as well just use a radial.

What else...ah yes, the flat pins offer greater contact area with the socket electrics, increasing current carrying capacity - the round continental plugs dont allow for much practical contact area, making things hotter.

Disagree. There have been many issues over the years with insufficient contact area and poor contact pressure causing sockets to fail under normal loads. The actual contact area in a BS1363 socket is quite low. Proper round pins (see IEC 60309 for an example) offer far more contact area than the flattened pins of a BS1363.

[WorldPowerLabs]

moving a spring loaded plastic shutter mechanism which covers the live and neutral holes - so nothing can be inserted in to them accidentally/by a child/whatever. As, in many other countries, not all plugs have an earth pin, it is not possible to do this as non-earthed plugs would be unable to be inserted.

That's how kids learn in the US.  "Don't put things into Mr. Sparky's eyes." 

It's usually a memorable lesson!

I'm surprised by how many people remove the grounding prong on our plugs when it gets in the way -- even folks who should know better (like physics professors)...

[SeanB]

Last week I was busy for a half hour persuading a socket to let go of the plug in it, after the live pin had welded itself to the pin. Cheap and nasty socket ( but certified to pass the relevant standard) and replaced with another one of a different brand. Used in the kitchen to run a kettle and a microwave, so load is 15A max. Now has a multiplug with thermal cutout, will see how that survives.