replying to Irreverent Maximus , Let's get it right! wrote:
nospam wrote:

Okay, I approached this thread as a joke. I mean, seriously. As you
have pointed out, the breaker protects the wiring of branch circuits.
That is the primary focus of the breaker since the breaker and branch
circuits are the only controllable factors. Once people start plugging
things into outlets, all bets are off.
With the advent of more and more electrical devices the need for a
reasonable compromise in providing more outlets, without dedication,
was needed and it was deemed that it was okay to increase the amperage
of branch circuits (110-120v duplex receptacles to be specific). The
protection and wiring of these receptacles is only to the face of the
receptacle. After that, it is up to the user to not be an idiot.
The U.L. listing is the rating that a device/cord is tested at, not the
rating of what it will be plugged into, nor is it the failure point that
the U.L. listed device has. The listing only proves that the device
will perform up to claimed rating. That is all. I could go on, but to
keep it short and simple I can give an example of something that might
surprise some people.
Look around your house, place of work, or any store that sells the
following:
http://preview.tinyurl.com/lubg6n9
Check out the U.L. listing tag near the plug. What does it state?
If it is a 16ga cord, like the one shown, it will have 13A as its
tested rating. I have a cord, don't know the AWG, but it is only
rated for 10A. Ever check out the 7A rating that the power cord that
plugs into the power supply of a Desktop? One might think that the
ampacity rating is solely because of the wire size, but they would be
wrong. Rather, It is the type of insulation versus intended voltage
that the insulation type of the wiring is made of. IIRC this is under
table 450.5(A) for flexible cords.
Anyone ever see a clock radio, with an 18ga cord, rated for 15A? A
lamp? I am not going to call "Get it Right", or whatever its nym is,
a troll, but maybe it can get this right:
How much horsepower is available at a 20A receptacle?
Merry Christmas!


... and you totally ignored NEC 110.3(1) (8): "Other factors that
contribute tothe practical safeguarding of persons using or likely to come
in contact with the equipment".

The issue if not about the ampacity of power cords, wall receptacles,
etc.. The issue is a "Listed" appliance can and is being interfaced with
a branch circuit that is beyond the Listing and/or labeling requirements
of the "Listed" appliance. It not "all bets are off" at the consumer
level. Such thinking totally ignores the "Testing for Public Safety" of
the Listing effort. The Engineers and Architect's of Record and well as
the local regulatory inspection agencies are NOT doing their job. The
installations cannot be NEC compliant because latent fire and shock
hazards do exists ... and the consumer doesn't even get a vote!

The smallest standard size circuit breaker is 15-amperes. Do you really
think a "Listing" agency, such as U.L., AGA, CSA, ETL, etc. would put
their listing mark on a product that couldn't operate safely from a
15-ampere circuit?

Does it make any sense to protect a fractional horsepower bathroom exhaust
fan with a 20-ampere circuit breaker? A 15-ampere circuit breaker would
provide more protected ... and is most likely what the "Listed" equipment
is rated for anyhow ... because of it's fractional horsepower load.

Horsepower available from a 20-ampere receptacle: 746 watts per
horsepower/hr. However, a motor is not a purely resisttive device. It
has inductive and capacitive characteristics. Subsequently to answer your
question, I'll need to know how many vars (a measure of imaginary power)
or volt-amperes (a measure of total power), or the power factor of the
motor to answer your question. In addition, is the line to line voltage
120, 240, etc? Makes a difference ... but obviously you already know that!

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