On Sun, 15 Jan 2017 16:26:39 -0000, trader_4 wrote:

On Saturday, January 14, 2017 at 4:53:16 PM UTC-5, James Wilkinson Sword wrote:
On Sat, 14 Jan 2017 16:21:37 -0000, trader_4 wrote:

On Friday, January 13, 2017 at 5:32:57 PM UTC-5, James Wilkinson Sword wrote:
On Fri, 13 Jan 2017 21:38:15 -0000, trader_4 wrote:

On Friday, January 13, 2017 at 4:23:27 PM UTC-5, James Wilkinson Sword wrote:
On Fri, 13 Jan 2017 21:16:45 -0000, trader_4 wrote:

And just like with that cord, if there is a partial short
in a branch circuit that produces a current under the breaker limit,
it can start a fire, without tripping the breaker. According to you,
you Britts have all your receptacles on one 30A circuit. What happens
if you have a partial short that results in a current of 10A?
You have ~2.5KW, which is more than enough to start a fire. Yet you
apparently live with that.

Fire can only start if the current is higher than the wire carrying it can take.

That's absolutely false. A piece of paper on an electric stove proves
it. In the real world, fires start from bad, loose connections, from
arcing, etc.

But heating the whole wire is far far worse.

The whole point is that if the lamp is shorted, say by inserting
a screwdriver in it, there will be a high current that exceeds
the 15A, 20A circuit breaker, tripping it almost instantly,
*before* the wire can get hot. Even if there is some odd short
that takes the current to just under the breaker limit, it
will will not generate anywhere near enough heat in a lamp cord
to create a fire. If you understood basic electricity, you could
do the math to see that you're wrong.

A wire that is meant to take 1A will get 19 squared times hotter at 19A. That's very hot.

No, it;s not very hot. If you did the math, you;d stop embarrassing
yourself. Resistance of 18g lamp cord is .02 ohms per meter. Put 20A
through it and you get a whopping 8 watts, distributed over a meter
of wire. That isn't "very hot", nowhere near what it takes to start
a fire. Where is a fire likely to actually start? Where the wire
is damaged, at bad connections that overheat or arc, etc. And those
fires will start even with 12g wire on a 20A circuit.

I have used a 13A extension cord at 13A 24/7. It gets well over body temperature. Multiply THAT by 19 squared.

Every wire should be fused at the limit of that wire. I can't believe you guys are stupid enough to have 1 amp cord protected at 15 amps.

I can't believe you're so stupid period.

Thanks for proving my point that you're an idiot. Your reply has no information in it whatsoever.

No, clearly the problem is that you can't understand or just ignore
the information
provided. As exemplified by your stupidity on claiming concrete
is an insulator. Everyone
here provided you with overwhelming info from credible source, eg
code authorities that cite concrete encased electrodes as one of
the preferred earth grounds, yet you just ignore it and drone on.
Now you're doing the same dumb thing again.

I have a multimeter, I know it's an insulator. But then my concrete isn't dunked below the water table like an electrode. We were discussing concrete slab under a house, which will not be even damp, or you'd have a very soggy carpet.

Again fool, look up concrete encased electrode.https://en.wikipedia.org/wiki/Ufer_ground

"When homes are built on concrete slabs, it is common practice to bring one end of the rebar up out of the concrete at a convenient location to make an easy connection point for the grounding electrode.[4]

The Ufer Ground is an electrical earth grounding method developed during World War II. It uses a concrete-encased electrode to improve grounding in dry areas. The technique is used in construction of concrete foundations.
During World War II, the U.S. Army required a grounding system for bomb storage vaults near Tucson and Flagstaff, Arizona. Conventional grounding systems did not work well in this location since the desert terrain had no water table and very little rainfall. The extremely dry soil conditions would have required hundreds of feet of copper rods to be inserted into the ground in order to create a low enough impedance ground to protect the buildings from lightning strikes.

You;re like a compass that constantly points in the wrong direction.
Pretty much whatever you say, we know it's wrong.

An electrode needs damp concrete to conduct. It's the water that conducts, aided by the surface area of the concrete. You need to put the concrete deep underground to make an electrode. I don't know about your weird concrete base housing, but ours has concrete round the edges, deep under the supporting walls. That foundation will probably touch the water table. So if there was a wire inside it, that wire would be earthed. But not the dry insulating parts of the concrete.

--
An old black-and-white photograph of a man milking a cow was sent to a photo-finishing company.
The man was sitting behind the cow, and all that was visible of him were his legs and feet.
A note accompanying the order read: "This is the only picture I have of my great grandfather. Please move the cow so I can see what he looked like."