On 12/16/2013 3:45 PM, Let's get it right! wrote:
replying to bud-- , Let's get it right! wrote:
null wrote:

(B-1 is protection of the cord of a listed device) Also B-3
(protection of listed extension cords). 15A receptacles are allowed on
20A circuits. You are saying that the listing requirements of devices
and extension cords with a 15A plug do not allow them on 20A circuits?
I see no reason to believe that is true (and it would be absurd).
Perhaps a cite? Try 110.2 (approved). "Listed" apparatus is normally
"approved" and 110.3-A (examination) would not normally be done. But
110.3-B (used in accordance with listing) is applicable. Fires are
likely from not using according to the instructions.


The problem isn't the listed device. The problem is branch circuit
protection (20-amperes) is not compatible with the listed devices.
Subsequently, the listed device is being allowed to operated beyond the
parameters for which it was listed (up to 15-ampere branch circuit
protection), and creates a fire/shock hazard because the listed device
could/does have the opportunity to fail not-safe!

Listed extension cords made with #18 wire are readily available. The
rating in the NEC for #18 cord is 10A (400.5). According to you, that
can't be used on even a 15A breaker.

The requirements for overcurrent protection of cords is in 240.5. There
are several methods of protection. "Listed" cords are considered
protected (240.5-B-3). UL know that cords with a 15A plug may be used on
20A circuits. The system is working as intended. The cord will have a
current or wattage rating. It up to the user to use the cord according
to the ratings provided.

For cordsets that we put together (field assembly), the wire must be #16
or larger on a 20A circuit (240.5-B-4). The NEC rating for #16 is 13A
(400.5). The NEC explicitly allows cords rated 13A on a 20A breaker.


Got any listed appliances that have NEMA 5-15 plug and cord sets that are
protected according to NEC? Highly likely.

Yes, it is highly likely.

Listed appliance (and lamps, etc) will have a cord large enough to
supply the appliance when used as instructed. Cords of listed appliance
cords are considered protected (240.5-B-1).

Appliances are protected as UL and the NEC intended.

The regulatory inspection
agency in change of inspecting your home/office probably screwed up!

Nonsense. They are enforcing the code as written.

Proof: On a 20-ampere branch circuit, load an extension cord until the
current draw approached 20-amperes. It can be done ... and have a fire
extinguisher on hand ... because it most probably will burn up ... and the
circuit breaker will not trip ... until there is a dead short.

Your breakers may only trip on dead shorts. Mine trip at the rated current.

And I use cords according to their rating.