Best place to buy 32A cable

Watts are units of energy, yes you will carry more watts at 240 volt but it is the current that causes heat. Both are 32 amp.
The heat loss of the cable will be I Squared R Voltage is not a factor.
What am I missing?
 
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NO !,

the voltage drop over the cable: Vdrop= Rcable x I,
is in both cases (at 12V or 230V) exactly the same
P = Vdrop x I,

just one remark,
12V specced cable might have much less isolation than 230V spec,
which means that it wont be safe to use, causing current leak or electrocution,
nothing todo with "glowing" the cable
 
bendyone said:
Watts are units of energy, yes you will carry more watts at 240 volt but it is the current that causes heat. Both are 32 amp.
The heat loss of the cable will be I Squared R Voltage is not a factor.
What am I missing?
Click to expand...

sorry my post crossed yours,
agree ofcause
 
4mm cable will probably be ok on a 32A supply over a 25m run, as long as you're not drawing 32A continuously.
If you're at, or close to drawing 32A at 25m then 6mm cable would be a better bet.
 
bendyone said:
Maybe you could help me out and explain why the cable would melt at 32amps.
Click to expand...

Without doing more calculations that I can be bothered with I can't tell you it would melt - however carrying 32A it would be heating 20 times as fast at 240V (UK mains of course isn't 240V but you knew that, didn't you) than 12V, P=IV is a pretty simple equation to apply. I thought that the govt was pushing (nanny state and all that) it a bit when they changed the regs to (in theory) stop unqualified people altering their own home electrics, I'm beginning to understand their reasoning.
 
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Elecglitch said:
Without doing more calculations that I can be bothered with I can't tell you it would melt - however carrying 32A it would be heating 20 times as fast at 240V (UK mains of course isn't 240V but you knew that, didn't you) than 12V, P=IV is a pretty simple equation to apply. I thought that the govt was pushing (nanny state and all that) it a bit when they changed the regs to (in theory) stop unqualified people altering their own home electrics, I'm beginning to understand their reasoning.
Click to expand...

Permit me to assist


A 12V DC cable carrying 32A will carry 12*32 = 384W

A 240 V AC cable carrying 32A will cary 240/sqrt(2) *32 *= approx 5.4 kW.
We times by 1/sqrt(2) as this is the average amplitude of a sinusoid, because we’re interested in the average power, not the peak power.

So just comparing the powers the cables are “rated” for, theres a factor of 5.4k/384 = 14 difference between the 12V and 240 v

Heat is released as lost energy from collisions between particles and the lattice or metal atoms.

At a higher potential *of 220 v ac the carriers will have a higher energy and speed, so there will be more collisions per second leading to more heat released per unit time.

I dought the DC rated wire insulation will be able to cope .

Think it's best to dissuade Jez from using E bay seemingly rated 32 A stuff intended for cars to carry Spanish shore power on board while his wife n kids are asleep .*
 
I alway thought it is wise to seek professional "qualified" advice and not believe things written on an internet forum. Thanks for confirming it.
 
Portofino said:
We times by 1/sqrt(2) as this is the average amplitude of a sinusoid, because we’re interested in the average power, not the peak power.
Click to expand...

Not quite, as the 240V (or 230V, in fact) quoted for UK mains is the RMS voltage, the peak is around 325V. Thus the scaling factor for the power remains nearer 20 than 14.
 
12v wire obviously isn't suitable for mains use.
4mm2 flex will be fine if you don't draw anywhere near the full 32A, else use 6mm2.
The only other thing to note is the voltage rating. Some (usually yellow) flex will only be rated for 110v. Flex suitable for 220v mains is probably going to be yellow or blue but colour alone is no guide.
Although it doesn't get that cold in Spain it's probably worth getting arctic flex so it stays flexible in the winter.

Google '3 core arctic flex 6mm' (or 4mm)

Here you go... https://www.jcelectrics.com/3183ab-6-arctic-blue-3-core-cable
 
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bendyone said:
I alway thought it is wise to seek professional "qualified" advice and not believe things written on an internet forum.
Click to expand...
As if professional/qualified advice couldn't be given on an internet forum.
Yes, it can be harder to separate the wheat from chaff on the web, but once you know your chicken, these days forums are a very efficient source for just about anything, imho.

In fact, coming to think of it, there's another electrical thing about which I'm curious to hear the forum views, will post it in a minute... :)
 
MapisM said:
As if professional/qualified advice couldn't be given on an internet forum.
Yes, it can be harder to separate the wheat from chaff on the web, but once you know your chicken, these days forums are a very efficient source for just about anything, imho.
Click to expand...

P you'r ofcause right, when you separate the wheat from the chaff, there is a lot of usefull and valuable information on this forum,
I'm in a very good position to testifie about this ;-)

but in bendyone's defence,
there is so much utterly wrong info in posts #27 and #28,
which he was merely responding at (I think)
 
BartW said:
P you'r ofcause right, when you separate the wheat from the chaff, there is a lot of usefull and valuable information on this forum,
I'm in a very good position to testifie about this ;-)

but in bendyone's defence,
there is so much utterly wrong info in posts #27 and #28,
which he was merely responding at (I think)
Click to expand...

Thanks
 
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