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AFCI and UL Standards
Mike, I am enjoying the lively discussion on AFCI protection. I
would like to add my observations:
1. I find nothing wrong with someone trying to test these devices
on their own, however, throwing up one's arms and stating these
devices have no merit based on the limited "garage"
testing is a little extreme. Perhaps a more reasonable approach
is to find out how UL tested the devices. I can think of a number
of reasons why Mr. Huddleston's tests may appear to give less
than reasonable results. A major one is the use of carbon arc
rods to simulate an arcing fault. Keeping in mind that carbon arc
rods are designed to maintain a consistent arc, the current wave
form may have looked too consistent to fall in the envelope of an
arcing fault. Remember, these devices have to be "smart"
enough to prevent nuisance trips.
2. UL standards.....I don't think that UL alone dictates
equipment standards. Remember, they are a listing agency that
establishes testing standards for devices to insure safety from
risk of fire, electric shock, or injury. As such, UL standards
apply to safety performance issues; noise levels generated,
failure modes, risk of shock or fire. UL rarely if ever gets
involved with performance issues of efficiency. UL listing is by
no means an indicator of quality.
3. Mr. Huddlestons findings would suggest more scrutiny
into the UL listed AFCI's. A number of years ago, a similar issue
were raised over "flammability tests" for infant
clothing and bedding. After inquiry by consumers (some of who had
lost infants) and in particular, "Consumer Magazine",
it was determined that testing programs conducted by UL were done
to exacting standards. However, the standards employed did not
adequately reward those manufacturers making truly fire proof
goods. As a result, "fire retardant" clothing and
material allowed a wide spectrum of material to share the same
listing. As a result of the scrutiny, UL changed their standards
of material testing.
4. I agree that manufacturers tend to cram a lot of their special
interests into standards and codes...look who makes up a large
part of the committees! The NEC and UL will listen to input from
others, especially if safety is at issue.
Keep up the good work!
Steinman, E. Chuck. - CPDA, chuck.steinman@ci.denver.co.us
Mike Holts Comment: I wonder what CPDA means.
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