Current Carrying Capacity of cables with different voltages

[D Skelton]

'Thou shalt not question Stephen Fry' - Wasn't that like the 11th commandment or something?! Lol

 

[shanky887614]

In Ac circuits the electrons vibrate pretty much around their own original position so no actual electron migration and in DC the electrons move so slow it make a snail look fast ....... look up 'speed of electricity' on Wiki and learn why everything you are taught is dumbed down and a lie just to make sure you dont get brain overload ..... classical physics is all you need to know .... advanced physics first rule is forget all the crap you were ever taught.

@sparky 351335 .... 300,000m/s is the speed of the propagation of the EMF not the electrons whizzing around as your answer implies if your going to google it make sure you understand what you read..

Simplist way to explain it.

Get a tube 5m long and fill with marbles. As you push one more in from one end another pops out the other but the ones inbetween move incredably slowly

 

[Darkwood]

Depends who your trying to explain this to shanky your explanation works to explain the speed concept but has the confusing angle of making one think the electrons (marbles) are delivering the energy but when you do this concept with AC you have no NET migration so yes it may satisfy the those who just need a visualisation of how it works but this is again a false concept to simplify the workings of the quantum realm.... ive studied quantum theory for 30yrs and it still screws my mind up because its a world that dosn't follow the rules of the Macro world so trying to convey it to someone who only know the real world is practically impossible....

 

[shanky887614]

Depends who your trying to explain this to shanky your explanation works to explain the speed concept but has the confusing angle of making one think the electrons (marbles) are delivering the energy but when you do this concept with AC you have no NET migration so yes it may satisfy the those who just need a visualisation of how it works but this is again a false concept to simplify the workings of the quantum realm.... ive studied quantum theory for 30yrs and it still screws my mind up because its a world that dosn't follow the rules of the Macro world so trying to convey it to someone who only know the real world is practically impossible....

True but its the easiest way to explain how something as slow moving as an electron can have a much larger affect. Quantom physics themselfs are complex because most people try to use known laws that act completely different in reguards to quantom science.

 

[Tiny Spark]

All you need to know is what they tell you in school that electric goes from + to -!

Oh wait...

 

[shanky887614]

All you need to know is what they tell you in school that electric goes from + to -!

Oh wait...

Lol that messes with a lot of peoples minds.

I forget which but electrons flow from pos to neg but electricity from neg to pos

 

[Des 56]

There must be "holes" in these arguments about the flow of electrons

I think its probably best to leave the quantum state to DW
Even with his extensive knowledge,to quote Richard Feyman,
"I think I can safely say no one understands quantum mechanics"

So there we are,there seems little hope of the likes of us getting to grips with this subject,at least not by the end of this thread :blush5:

 

[D Skelton]

What's more, we also know either our current quantum theory or our theory of relativity is wrong, maybe even BOTH, so essentially we're all basing our sums on something which is a coin flip at best!

 

[Darkwood]

Its not that its wrong its the quantum equations we have prove very precise and accurate what is wrong with them is unification of different areas of the quantum world namely gravity, we hae well founded and tested equations that can explain differing areas of the quantum world but we dont have one that links them together or TOE (Theory Of Everything).

As we progress and discover more like last years big find (Higgs Boson) the elusive giver of mass and the recent discovery of new exotic particles the links between the various areas are slowly been made.... dark matter should hopefully be detected within the next 5yrs 'IF IT EXISTS!!!'

 

[Gardner]

I would think it would be the same. Heating is a function of current rather than voltage. Now if your cable is exposed verses imbedded in insulation than there would be a difference from smothered heat dissipation.

 

[D Skelton]

But we know a link doesn't exist between wider quantum theory and relativity (the minutely small and the infinitely large) because one of them (at least) is fundamentally wrong, we know this to be the case but the reason we still use both theories is because they fit what we need them for. Christ we still use newtonian theory even though we definitely know that is wrong. Science is about using what you have until you find something better or more suited to your needs.

 

[Darkwood]

We could always follow the bible bashers ... at least every question can be answered the same ... cos God made it that way!

I had 2 bible bashers at my door so i explained im an Athiest .... they ask me why im an atheist to which i replied 'Because god made me this way' .... their faces were a picture lol

 

[Tiny Spark]

Blaggedhead.org

 

[D Skelton]

I live right next to a Jehova's witnesses kingdom hall and used to get them at the door all the time when we first moved in. They always used to introduce themselves to which I'd always reply with one word... 'Dinosaurs!'

They've stopped coming round now

 

[Mr Hehound]

What's more, we also know either our current quantum theory or our theory of relativity is wrong, maybe even BOTH, so essentially we're all basing our sums on something which is a coin flip at best!

This is why physics is so ace. It evolves as we learn more.

I often lament that its a shame the young have to decide what to study before they're really old enough to understand how interesting some subjects are regardless of whether they're hard or mathmatical.

We'd have alot more physicists and engineers and alot less media studies graduates than we have now.

 

[Darkwood]

If i listened to my school Physics teacher i'd be crap at my job.. i saw him 15yrs later and asked him some indepth physics questions and he could't respond and then ask why we were taught that there was only 3 states of matter ... he said that they was the important ones ...i said they only accounted for less than 3% of the states of matter in the universe and he negated to express that almost all matter was composed of a 4th state............

Ive hated dumbed down teaching ever since ........... its Santa clause and the Tooth Fairy for graduate .... SAD!

 

[Mr Hehound]

If i listened to my school Physics teacher i'd be crap at my job.. i saw him 15yrs later and asked him some indepth physics questions and he could't respond and then ask why we were taught that there was only 3 states of matter ... he said that they was the important ones ...i said they only accounted for less than 3% of the states of matter in the universe and he negated to express that almost all matter was composed of a 4th state............

Ive hated dumbed down teaching ever since ........... its Santa clause and the Tooth Fairy for graduate .... SAD!

Gas plasma? What is it you do?

Think the teacher thing varies tbh. Some good some bad. Until university level they're a bit ham strung by limitations of the syllabus they are told to teach I think.

 

[Darkwood]

Yep PLASMA ...

I repair, upgade machines, design control systems for machinery and industrial electrical installations mainly but can backtrck to the simple stuff to fill the day if need be.

I know what your saying with the teacher thing but it still get my rag that they still teach the basics wrong because its easier if they taught the real world of physics it will weed out the not so intelligent and promote those genuinely interested rather than just keeping the pass rate high and filling the country with numpties.

I went in my old school the other day and was shocked to find a large poster on the wall showing the '9' planets of the solar system not the 8 as we know now...pluto was downgraded several yrs ago but the school literature has been changed due to costs... the teacher explained they are now told the books are out of date so i said ok but isn't it sending a confusing message to have the out-dated posters up ...think he got my point

 

[Tiny Spark]

Fully agree darkwood.
Whats the point of having a A* in science and a high pass rate if everything you are taught is wrong?

Ide rather be taught right first time round and not have my head filled with lies and dumbed down stuff.

It only seems like yesterday I was leaving school (11 years ago) but the gaps in knowledge between what I knew at 16 and the young apprentices we take on seem to be huge.

We even had to teach 1 lad how to use a calc so he could attempt his lvl 2 key skills maths exam!!

 

[Darkwood]

They use calculators now!!!! OMG what next virtual holograms to tell them all the answers they don't know:banghead: