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<div class="moz-cite-prefix"><br>
Taking Jarmo's example a step further, if you unroll the 3 wires
so that they are flat, place those 3 end to end and<br>
then unroll the larger 975 KCMIL wire and lay it next to those 3
placed end to end,<br>
the 3 smaller circumferences will be "square root of 3 times"
longer or, about 1.732 times longer than <br>
the larger 975 KCMIL wire. That's 1.732 times more breathing
(cooling) area.<br>
Was that about the amount of difference you saw in the NEC table,
Larry ? 1.7 times or so ?<br>
<br>
boB <br>
<br>
<br>
On 12/2/2014 4:45 PM, <a class="moz-txt-link-abbreviated" href="mailto:boB@midnitesolar.com">boB@midnitesolar.com</a> wrote:<br>
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<blockquote cite="mid:547E5D0E.6090603@midnitesolar.com" type="cite">
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VERY nice example, Jarmo !<br>
<br>
Hey, one day, probably after we are all gone, maybe everybody
will be using high temperatue<br>
superconductors and we won't have to worry about wire size any
more.<br>
<br>
If they can make them work well with AC....<br>
<br>
boB<br>
<br>
On 12/2/2014 4:26 PM, <a moz-do-not-send="true"
class="moz-txt-link-abbreviated"
href="mailto:Jarmo.Venalainen@schneider-electric.com">Jarmo.Venalainen@schneider-electric.com</a>
wrote:<br>
</div>
<blockquote
cite="mid:OF499AA91E.171E9D71-ON88257DA3.00022874-88257DA3.000265FF@US.Schneider-Electric.com"
type="cite"><font size="2" face="sans-serif">Hi:</font> <br>
<br>
<font size="2" face="sans-serif">Look at it this way,</font> <br>
<br>
<font size="2" face="sans-serif">The three conductors in
parallel can handle more current because they have more
surface area with which to dissipate heat. Or to put it
another way, the heat from the middle of the thick 975 kCM
cant get out and so the wire stays hotter.</font> <br>
<br>
<font size="2" face="sans-serif">See picture,</font> <br>
<br>
<img src="cid:part2.06010308.05070705@midnitesolar.com"> <br>
<br>
<font size="2" face="sans-serif">JARMO<br>
</font><font size="3" color="#008000">_____________________________________________________________________________________</font><font
size="3"> <br>
</font><font size="1" face="Arial"><b><br>
Jarmo Venalainen</b> | </font><font size="1" face="Arial"
color="#008000"><b> Schneider Electric </b></font><font
size="1" face="Arial"><b> | Solar Business</b> | <b>CANADA</b>
| <b>Training & Development Specialist - Senior</b> <b><br>
Phone:</b> +604-422-2528 | <b>Fax:</b> +604-420-1591 |
<b>Mobile:</b> +604-505-0291 <b><br>
Email:</b> </font><a moz-do-not-send="true"
href="mailto:jarmo.venalainen@schneider-electric.com"><font
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target="_blank"><font size="1" face="Arial" color="blue"><u>
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| <b>Address:</b> 3700 Gilmore Way, Burnaby, BC V5G4M1 <br>
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<br>
<br>
<table width="100%">
<tbody>
<tr valign="top">
<td><font size="1" face="sans-serif" color="#5f5f5f">From:</font>
</td>
<td><font size="1" face="sans-serif">Larry <a
moz-do-not-send="true" class="moz-txt-link-rfc2396E"
href="mailto:larry@starlightsolar.com"><larry@starlightsolar.com></a></font>
</td>
</tr>
<tr valign="top">
<td><font size="1" face="sans-serif" color="#5f5f5f">To:</font>
</td>
<td><font size="1" face="sans-serif">RE-wrenches <a
moz-do-not-send="true" class="moz-txt-link-rfc2396E"
href="mailto:re-wrenches@lists.re-wrenches.org"><re-wrenches@lists.re-wrenches.org></a>,
</font> </td>
</tr>
<tr valign="top">
<td><font size="1" face="sans-serif" color="#5f5f5f">Date:</font>
</td>
<td><font size="1" face="sans-serif">12/02/2014 03:30 PM</font>
</td>
</tr>
<tr valign="top">
<td><font size="1" face="sans-serif" color="#5f5f5f">Subject:</font>
</td>
<td><font size="1" face="sans-serif">Re: [RE-wrenches]
Parallel Wire combining</font> </td>
</tr>
<tr valign="top">
<td><font size="1" face="sans-serif" color="#5f5f5f">Sent
by:</font> </td>
<td><font size="1" face="sans-serif">"RE-wrenches" <a
moz-do-not-send="true" class="moz-txt-link-rfc2396E"
href="mailto:re-wrenches-bounces@lists.re-wrenches.org"><re-wrenches-bounces@lists.re-wrenches.org></a></font></td>
</tr>
</tbody>
</table>
<br>
<hr noshade="noshade"> <br>
<br>
<br>
<font size="3">Hey boB,<br>
<br>
This is the reference table I was using. They show 325 AWG and
325kCM refer to the same diameter cable but I should have used
kcm for clarity. <br>
<br>
If all insulation/temp rating is the same we are back to my
original question. Anyone else able to explain this? To be
safe I am leaning toward using the combined CM number to size
for current rather than 3 times the ampacity as that just
makes no sense to me. <br>
<br>
</font><img src="cid:part10.02040604.09070809@midnitesolar.com"
width="753" height="658"><font size="3"><br>
On 12/2/14 3:54 PM, </font><a moz-do-not-send="true"
href="mailto:boB@midnitesolar.com"><font size="3" color="blue"><u>boB@midnitesolar.com</u></font></a><font
size="3"> wrote:</font> <br>
<font size="3"><br>
The "area" of the conductor will be 3 times and you would
think that the NEC Ampacity would also be 3 times<br>
that of one conductor. But one LARGE conductor with the same
area might not be as high as you think<br>
because of insulation. I would think that ampacity of 3
cables in parallel would be 3 times. But probably<br>
not when you take a single cable of the 3X area out of the NEC
table. (I haven't looked at this to verify)<br>
<br>
Also, Larry, 325 AWG 750 AWG (gauge) wire is a bit too small
for this, don't you think ?<br>
<br>
I know... You mean circular mils...<br>
boB<br>
<br>
</font> <br>
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