On 12/17/2013 9:45 AM, Let's get it right! wrote:
replying to Irreverent Maximus , Let's get it right! wrote:
nospam wrote:

"bud--" wrote in message
b.com...
I guess this device should be unlisted:
http://www.cesco.com/b2c/product/471640 It appears that it accepts
both 15 and 20 amp plugs. I wonder why that
is?
I have shopped at many stores and have yet to see an appliance with a
true twenty amp plug. I am so confused...


Articles 100 thru 400 of NEC are mandatory. Only after Article 400 can
you deviate from for specific applications.

A "Listed" device is only "Protected" when applied within it's listing
requirements and labeling. If you don't provide branch circuit protection
compatible with the "Listed" device listing requirements and labeling, it
not "Protected" according to NEC. Subsequently, if you provide 20-ampere
branch circuit protection to circuit intended to interface with "Listed"
devices, the "Listed" devices will not be "Protected".

Cord overcurrent protection for listed cords and appliances is covered
in 240.5-B-1 and 3. "Listed" cords and appliances are protected when
listing requirements are followed.

A single, dedicated NEMA 5-15 receptacle is allowed to be interfaced with
a 20-ampere circuit breaker ... but not multiple 15 ampere receptacles.

A single 15A receptacle can not be the only receptacle on a 20A breaker.
Multiple 15A receptacles are allowed.

In addition, the steady state current draw on a NEMA 5-15 receptacle
should be limited to about 13-amperes (allowing for a 2-ampere margin)
according to NEC.

"Continuous" loads (over 3 hours) are limited to 80%.

When there are 2 or more receptacles, the NEC also wants an 80% limit.
This is not enforceable. And UL does not have that restriction. A 15A
load may have a 15A plug.

A 20-ampere circuit breaker would allow for a 7-ampere
margin which would expose resistive components (such as power cords) to
over 75% more real power than what they are listed at.


The power cord,
plug, etc. will burn up under such circumstances, and a fused "Listed"
device will not protect the power cord of that "Listed" device.

A "listed device" will have a cord large enough to be adequate when the
device is used according to manufacturer instructions. The cord is
allowed by the NEC (240.5-B-1).