Sorry Lew, but I just don't trust you <G>.
While your line-loss argument is valid for a conductor that is
marginal or undersized for the load, the law of diminishing returns
catches up pretty quick. I simply don't accept your assertion that an
11 amp load heats #14 wire enough to degrade the insulation. The wire
length required to get a 2% voltage drop on #14 wire at 10 amps is 90
feet. At 30 feet of total wire length (15 ft x 2), voltage drop and
heat simply won't be a big factor in this application. #14 is
adequate. #12 is what I would use. #10 won't hurt anything.
My whole point is this. After your wire size is adequate for the
task, you can't just arbitrarily jump up a couple of sizes and say,
"Oh well, the electricity savings will pay for it." In an industrial
application where the wire you install powers a motor that runs 24/7
at full load, maybe; but in a home shop environment, we may not live
long enough to see the payback.
I think we done beat this horse to death. You have a nice day.
"In theory, theory and practice are the same, but in practice, they
Don't assume that your 14 ga conductor from an off-shore source has Cu
purity levels for them to play by North American charts. Same thing
for their insulation standards. Also, thermal increases along the
length due to resistance is not linear with conductor length. Add to
that, that inductive loads on a partially coiled 14 ga wire with an 11
amp load can geberate localized heat, and the whole 'perfect' argument
goes out the window.
I have seen, with my own eyes, that 50' cords from off-shore suppliers
(which means most cords) rated at 14 gauge AWG shrivel up into snake-
mottling-like messes by ordinary uses on jobsites. And we're not
talking about tables-saws or compressors either.
The argument you make about pay-back makes sense.... from 12 gauge on
You said it.
Too bad the horse is dead. Maybe some mouth-to-mouth?
If you need a cord, buying a molded cord set will be lowest cost solution.
Sounds like a personal problem to me<G>.
Everything, including man, starts the inevitable march to the junk yard,
the day it is put in service.
An 11A load on a #14AWG wire, produces heat.
Heat is the enemy of insulation.
Sooner or later it bites you.
> The wire
SFWIW, what some often forget in these discussions is the 80% rule.
The full load continuous current permitted by a molded case circuit such
as found in the typical load center or panelboard is 80% of the
nameplate value as defined by NEC.
Thus a 15A C'Bkr, used for #14AWG conductor protection, will allow 12A
(15x80%) on a continuous basis.
Above 12A, you are operating on the time derate curve of the C'Bkr.
Your choice of #12AWG for this application is an improvement over
#14AWG, and is economically a good one.
Many years ago, I decided not to worry about wire size and standardized
on #10AWG for all cordage applications in my shop.
Strictly a personal choice.
I have found that with a little patience and making purchases when you
are not under the gun, you often find sales on things including #10AWG
cord sets, which is when I buy them; however, even at full price, the
difference between #12AWG and #10AWG, 25 ft molded cord sets rarely
exceeds the cost of a decent 12 pack.
As indicated, power savings alone is not the total answer. It is a
combination of power savings and insulation life of not only the
conductors, but also the power consuming device.
Trying to calculate the cost of reduced insulation life is an exercise I
leave to others.
> In an industrial
Actually, in an industrial application, the payback period rarely
exceeds 2 years, thus they tend not to have much spare capacity in their
One final thought.
If this discussion has raised the awareness of the group to the fallacy
of trying to use relatively small conductor size extension cords for
relatively long applications, it will have served it's purpose.
Oh, you mean other people besides me and you are still following this
And a fine and pleasant discussion it's been too.
But I still don't trust you. <G>
"We should be careful to get out of an experience only the wisdom
that is in it - and stop there; lest we be like the cat that sits
on a hot stove-lid. She will never sit down on a hot stove-lid
again---and that is well; but also she will never sit down on a cold
one anymore." - Mark Twain
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