Re: Electrical question

DonkeyHody wrote:

True, but you failed to consider that romex might be appropriate when
you proposed a #10 cordset as the "lowest cost solution available".

If you need a cord, buying a molded cord set will be lowest cost solution.

I simply don't accept your assertion that an
11 amp load heats #14 wire enough to degrade the insulation.

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
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.

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.

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."

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
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.

Actually, in an industrial application, the payback period rarely exceeds 2 years, thus they tend not to have much spare capacity in their designs.

I think we done beat this horse to death. You have a nice day.

OK.

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.


Lew
.

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