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Flexible cable for generator backfeed use? - Page 20

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Posted by Jamey Kirby on August 19, 2005, 12:22 am

More surface area is better; that is what I have heard. I use 4/0
welding cables from my battery bank to my inverter. I was using battery
cable before and the wire would get warm when charging at 30 amps AC.
Using the welding cable, I have no detectable heat in the lines to my
battery bank.

I may know nothing about the physics, but I have heard from more than
one person that the more surface area, the better the conductor.


-----Original Message-----
From: Mark [mailto:me@privacy.net]
Posted At: Thursday, August 18, 2005 1:38 PM
Posted To: alt.energy.homepower
Conversation: Flexible cable for generator backfeed use?
Subject: Re: Flexible cable for generator backfeed use?


panel, but

but since

larger or what?

That is correct that gauge is gauge.  I think the OP is asking if there
a different AWG requirement for amperage loads based on if the wire is
solid or stranded.

I do recall something about people who build their own hot-rods and
their battery to the rear for better traction.  They use the same AWG (4
believe) welders cable to do this since it's easier and more flexible.
they have to crank the car too long for some reason, you risk heating
cable too much and weaken the sheathing.

If NEC says gauge is gauge and solid vs. stranded doesn't matter, I
there is no issue.

Posted by nospam.clare.nce on August 19, 2005, 6:32 pm

On Thu, 18 Aug 2005 17:22:32 -0700, "Jamey Kirby"

This is true in the case of high frequency AC. With DC it is TOTALLY
irrelevent. With 60 hz AC the effect is so minimal as to be almost
impossible to measure.

Posted by Me on August 19, 2005, 6:36 pm

Only true for AC Power as AC power runs on the surface of the conductor,
whereas DC Runs thru the total crosssection of the conductor.


Posted by tim on August 21, 2005, 3:56 am

I think the poster is more talking about the more surface area, the
better the thermal radiation characteristics, and the cooler the
wire will operate for a given load.  BTW, skin effect only really
begins to operate at RF frequencies.

Posted by Vaughn Simon on August 19, 2005, 6:01 pm


     Actually, if you dig into the NEC you will find diffirent ampacities
listed for different cables of the same guage.  This is because some types
of insulation can take higher heat without damaege.  The NEC is a safety
code.  As such, it tends to ignore effiiciency (as well as other mundane
practical matters).


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