Originally Posted by gottodo1
Wuzzat, I'm sure there's information about an Arc. Do you know what AFCI's are certified against, is it an ANSI, ISO etc etc standard? I can find out what the criteria are or at least how they test it if they don't have design criteria.
I was unable to find it.
And as I recall, even the online patents that I searched did not shed much light on exactly how their "signature analysis" is supposed to work. The maker can always claim a Proprietary Method.
Surely at the end of the assembly line these devices are tested, go/no-go, before sold. I'd hope they are tested against bad arcs and good arcs, but I'd like to see that test setup. And how closely do the test arcs match the real world?
And it's not just bad arcs. If you know some programming languages, apparently AFCIs work according to
IF (more than 5A flowing AND bad arc) THEN trip ELSE (don't bother the home owner).
The current flow is another variable in this arc detection strategy.
More generally, and knowing about thishttp://en.wikipedia.org/wiki/Sensitivity_and_specificity
as a limit on how well these things can possibly work, I'd like to see the numbers for AFCIs. Numbers are harder to spin.
Let's say you have a genuine bad arc inside a lamp switch.
Well, the switch is housed in a fire resistant shell and a bad switch will make itself known with how the bulb behaves.
So how many house fires did we have before these things and how many do we have now?
With GFCIs there is probably a bias in favor of tripping if the thing is in doubt. I've never heard complaints about a GFCI not tripping and the person continuing to get a shock.