How many appliances should be on one breaker?

[James Wilkinson Sword]

What are you talking about? A 1A cord may only take 10 amps through it during a short, and catch fire. Yet the 15A breaker won't trip.

[trader_4]

Reality, the way thing are.

A 1A cord may only take 10 amps through it during a short, and catch fire. Yet the 15A breaker won't trip.

Never said anything different. But a direct short will produce enough current to trip the breaker, ending the problem before the cord can heat up. Happens all the time. Stick a screwdriver in a light socket and it causes a current that trips the breaker right away.

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.

[James Wilkinson Sword]

As I just said, the resistance of the thin cord won't let enough pass to trip the breaker.

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

[trader_4]

BS. Just stop. Typical lamp cord wire will easily carry way more than required to quickly trip the 15A circuit breaker, for a short duration. What do you think the resistance of a couple meters of lamp cord is? And if you don't believe it, go stick a screwdriver in an unfused lamp socket and see.

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.

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

[James Wilkinson Sword]

And all shorts have no resistance of their own of course....

But heating the whole wire is far far worse.

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

[James Wilkinson Sword]

On Fri, 13 Jan 2017 21:51:30 -0000, Uncle Monster w= rote:

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depending on the appliance.

lug. I imagine it was less expensive than a separate fuse holder in the = housing of the item. =E3=83=BD(=E3=83=85)=E3=83=8E

It protects the cord. The Brits invented that years ago. Your country = is so far behind....

-- =

Condoms aren't completely safe. A friend of mine was wearing one and go= t hit by a bus.

[FromTheRafters]

You left out the part about being barefoot on concrete after spilling a bucket of saltwater. Details matter.

[...]

[gfretwell]

We just require that "fixture wires" be of sufficient size to operate the breaker. (typically 18 ga for 15 and 20a circuits)

[gfretwell]

If you have a cord less than the "fixture wire" standard (

[trader_4]

That shorts have resistance of their own is part of the whole point. You can't have it both ways. First you argue that a short in a lamp is going to create a fire from the lamp cord if it's not fused. Then you claim the short limits the current because of it's resistance.

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.

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.

[James Wilkinson Sword]

It could easily limit it to anywhere between 1A and 15A, overloading the wire but not tripping the breaker.

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

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.

[gfretwell]

a wire meant to handle 1a would be between 29 and 30 gauge and you will never see that used for 120 or 240v. I pointed out earlier the smallest "fixture wire" allowed in the NEC is 18 gauge.(1mm)

[James Wilkinson Sword]

I've seen 2A wires. What is the difference between 2 squared heating and 19 squared heating?

[gfretwell]

You may see them over there where you fuse plugs and the chinks use some pretty cheap wire in those christmas light sets but they do have a fuse in the plug. They deal with unfused plugs here be requiring a minimum of 18 ga. That will hold 16a although the NEC limits it to 7. In a bolted fault, that is more than enough to trip a 20 breaker. The equipment that will get listed with an 18ga cord will draw less than 7a, Usually it is just a lamp or a radio.

[James Wilkinson Sword]

If you can't see that a 1A fuse is preferable to a 15A fuse, you're an idiot.

[James Wilkinson Sword]

The simplest thing to do is to fuse the appliance at its rating.

[trader_4]

On Saturday, January 14, 2017 at 4:53:16 PM UTC-5, James Wilkinson Sword wr ote:

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1A to 13A depending on the appliance.

an plug anything into an outlet, if it's a 13A outlet, your 0.5A table lamp doesn't have its cord protected against fire from a short.

atch fire. Yet the 15A breaker won't trip.

ss to trip the breaker.

wire but not tripping the breaker.

Yes, that's theoretically possible, but the wire will not heat anywhere near enough to create a fire. Do the math.

it can take.

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.

eve you guys are stupid enough to have 1 amp cord protected at 15 amps.

information in it whatsoever.

t dunked below the water table like an electrode. We were discussing concr ete slab under a house, which will not be even damp, or you'd have a very s oggy carpet.

Again fool, look up concrete encased electrode.https://en.wikipedia.org/wik i/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 a n easy connection point for the grounding electrode.[4]

The Ufer Ground is an electrical earth grounding method developed during Wo rld War II. It uses a concrete-encased electrode to improve grounding in dr y areas. The technique is used in construction of concrete foundations. During World War II, the U.S. Army required a grounding system for bomb sto rage vaults near Tucson and Flagstaff, Arizona. Conventional grounding syst ems did not work well in this location since the desert terrain had no wate r table and very little rainfall. The extremely dry soil conditions would h ave 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.

[trader_4]

James can't even apply Ohm's Law. 18g wire has a resistance of .02 ohms per meter. Put 20A through it and you get 8 watts. That's 8 watts distributed along a meter of wire. Actually, I guess it's 8 x 2, since there are two wires in a lamp cord. But 16W along a meter of wire is very little heat. Go over 20A and the breaker will open. And we have the everday experience where if this was a real problem, houses would be burning down from it and it would be addressed in the code. Obviously it's not happening. Plus, as I pointed out earlier, a direct, serious short will greatly exceed 20A, tripping the breaker quickly, before the wire heats up.

[gfretwell]

Why would I put a 1a fuse on a 16a conductor? If the equipment requires supplemental protection, there will be a fuse in it.

[gfretwell]

Evidently they have 30ga wire on their 30a ring circuits so they need fuses in the plugs. I guess the British Empire never colonized a place with copper ore.