Thanks for the link. I figured they'd obviously have to be more complex than the standard thermal/magnetic or even amplified GFI types.
The only way I can see for them to work is for the circuitry to look for short pulses of increased current but not trip on longer pulses. I can see how such a circuit could be developed with simple op-amps etc. in integrated form, though I wouldn't be surprised if they actually use a micro-controller to analyze the current pulses.
I just wondered if any more technical details on the actual arrangement were available.
Does the AFI rely on the control circuitry to trip on normal overcurrent, or does it incorporate a normal thermal/magnetic trip as a backup?
Originally posted by sparky: .......have you ever heard the expression 'tail waggin' the dog'???
Virgil; yes there's a test button on the breaker itself, just like a GFI. I just haven't found a tester to plug in thoughout the circuit like the one's used for receptacles with the GFI tester. where would i get a calculated arc of say, 76watts's
Originally posted by sparky: http://www.zlan.com/afci_c4.htm Paul, i could'nt really answer any of your Q's , this (check pix in link) is definitly not my forte' . i'd like to know how to detect a bad AFCI
Thanks for that. The diagrams & notes on that site are very helpful. Looks as though as I was right about the microprocessor analyzing the current.
Did you follow the links there to the pages about testing an AFCI?
They seem to be using another micro-driven test unit which stores typical arc waveforms and then re-generates them to test the breaker, except it's done via the non-shunted neutral line only in order to keep the current down.