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26 minutes ago, studiot said:

You should not be using 1.5 mm² for power wiring in the UK.

Power should be at least 2.5mm².

 

That cable is meant for lighting circuits.

It used to be also used for direct spurs off a ring main of less than 2m length, but I think that is now frowned upon.

im just giving 1.5 as example. i just need to know if power loss is more with lower volt given the same wire and same current. not as percentage of each power. just simply which would heat up faster.

6 hours ago, John Cuthber said:

The current rating is pretty much independent of the voltage.

If the current is too high, the wire overheats and the insulation melts.

If the wire is on the surface of the wall (unenclosed) then the heat can escape and the cable will carry more current before it overheats.
If the cable is in an enclosed space like a conduit, there's less chance for heat to escape so, to stop it overheating, you have to ensure that the current is lower.

As Swansont has pointed out, the derating can be complicated.

It's best (In most places, it's a legal requirement) to ask an electrician.

 

 

thanks all, now i understand this. the first line is the answer i looking for. i just needed more info on it, got it in quora

3 hours ago, swansont said:

The heat dissipation is based on P = I^2R, so lowering the voltage and increasing the current means more power dissipated in the wire.  

P = IV would include the voltage drop across the load, which should be much larger than the drop along the wire itself.

 

IOW, if you have a ~1.1 kW device, at 1100 V it draws 1 A. At 200 V it requires 5.5 A. The power dissipated in the wire goes up by about a factor of 30 (though for a length of wire with a resistance of 0.1 ohm, this is going from 0.1 W to ~3 W. That's the issue. It's negligible in terms of the overall load, but can be significant for a thin bit of wire)

 

So power loss rate would be same for say 1000V 5A versus 100V 5A ? This is what my question is.

I need to know if i can still run same amps rated for 1100v on a 200v circuit. or if i need to get bigger cable to run same amps at lower volt

4 hours ago, studiot said:

Pity you edited this before I could respond to the original.

It is not a good idea to remove the original question.

Yes I would expect the current density in a cable designed for much higher voltage to be lower than at the lower voltage.

This is simply because the insulation surrounding the conductor will be thicker and therefore also a greater insulator of heat.

This does not mean you can increase the current in a higher voltage cable and still meet regulations.

I note you application is a 16 amp circuit, which sound domestic to me, with 1.5mm² conductors.

This sounds European.

 

Note that the 1.5mm² is not the physical cross sectional area of the cable, but an equivalent depending upon the cable type, (stranded, solid etc) as well as the insulation type.
This is determined by the manufacturer.

Note also that the insulation has to withstand the peak to peak voltage plus a safety factor.

This will not be your 200v stated.

 

Another very important factor you should consider, often overlooked by the inexperienced, is the cable length. Particularly as you appear to want to run it near maximum current.

In these circumstances the cable sizing is often limited by acceptable voltage drop and therefore lenths, rather than current or voltage per se.
At some point you will need to select a larger section to avoid unacceptable voltage drop.

the original was just asking what "in conduit trunking" is. english is not my native so i didnt knew. plus i added more info on my main question since my intended question was missed because i was too vague.

thanks i totaly forgot about sizing up to minimize loss. its for wiring our new house, since the profesionals here in my place are plain dumb. plus electricians dont do the controlled testing to know these things and lack the scientific knowledge. so its a science guy job to figure these kind

34 minutes ago, John Cuthber said:

The current rating is pretty much independent of the voltage.

If the current is too high, the wire overheats and the insulation melts.

If the wire is on the surface of the wall (unenclosed) then the heat can escape and the cable will carry more current before it overheats.
If the cable is in an enclosed space like a conduit, there's less chance for heat to escape so, to stop it overheating, you have to ensure that the current is lower.

As Swansont has pointed out, the derating can be complicated.

It's best (In most places, it's a legal requirement) to ask an electrician.

 

 

really? i always imagine high volt allows for more current before overheat.

[edited: now i know conduit spec meaning]

[edited] My question was vague, what i want is, wire specs are tested at 1100v , where for example 1.5sq mm copper is rated at 16amp.

But my application is 200v, i would guess that lower volt heats up wire faster. so should i use R=V/I to lower amp  for 200v ? or the resistance is independent of the voltage.

Texas Holdem (consisting 6 players)

i got AA as starting hand, what are chances of there being another A on one of the 5 cards on table? what are chances of 2 other A on the 5?

1. So my question is, when u have pair as start. What are chances of you getting "3 of a kind" and "four of a kind"?

2. Unlike commonsense, I believe starting hand of 10 J is slightly better than K A, since u can make straights on both sides. Am i right? who can calculate it? please

Ouh I make them with brailles, they the best. Because it helps my dog to exercise by playing catch. Dog would bark and spot it by sound feedback by the raised dots

yes I love the bracelet, how did u guys know. bracelets are my hobby OMG

 

Can you phrase that with proper grammar please

 

first time i herd below 0K , hv u herd other news about below 0 elsewhere? you think the claims are reasonable?

 

Well science is ongoing process, so old thoughts about science always are changed or improved upon over hundreds of years, so its very possible it aint the limit like fiveworlds telling.

and 5worlds, I don't see why lia needs to rephrase it, as even a 10 year old can read that. if u have mental disability for not being able to make sense of partial info, you are indeed unlucky. any proper human can tell its a human by a circle and 3 lines, without needing to draw all the correct proportions and colours and shadings. nw u must get it. dnt be such hypocrite!

ya i know exothrmic, i stateed tht in reply, Captian Panic u give most scientific/best answer (i post this in 2 other forums, both more active thn this more ans)

because the ones who decide what is "the most comfortable temperature" are northern europeans, mainly British.

 

 

Because we are exothermic creatures.

i dont understand both, i have also test this with ac and thermomtr and why is 36C hot becoz we release heat???

Why is it the most comfortable temperature 22 to 26*C, and anything above 30C is hot when our body is 36*C

Does aplying oils on rusty metal witout 1st cleaning off the surface rust still prevents furthur rusting as long as the oil is there, or rusting can still continue inside?

Is there liquid or something that can wipe off rusts like magic

good ans, that what i tot of too, but jst posting hoping sum1 might share real experice strange thing to ponder on, and my vocabulary jst grew, havnt heard of charlatan before ;]

im 20 and dont believe in stupid Gods from early this year, but this is so strange:

well, it was 3 years back i think, Henry Hinn (younger bro of Benny Hinn,the famous preacher,healer) was hving crusade in our city, on football field(not stadium), after his prayer, he proclaim miracle healings, the strange one among those is: on the opp side to the podium he was standing was a 5story building, where people are wacthing from the top 2 veranda, He said (i dont remem exact) pointing towards that veranda, ''The girl with Cancer raise up your hand, your healed'', than 1 girl around 35 (on top floor veranda) raise her hand. WTF is that?