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Don’t even get me started on AFCIs. At least the behavior of GFCIs is well-defined. The AFCI thing is a money grab.
by anikom15 4y ago
Don’t even get me started on AFCIs. At least the behavior of GFCIs is well-defined.
The AFCI thing is a money grab.
- jxramos 4y agowhy's that, is there some guarantee they fail to live up to? Is there something probabilistic to them or something?
- londons_explore 4y agoAFCI's are of dubious effectiveness at their purpose (preventing fires). They're kinda snake oil because each manufacturer won't tell you under what exact conditions they'll trip. Somehow the law in the USA now requires them on every circuit, although they aren't used at all in Europe (which has a higher voltage yet far fewer electrical deaths).
- 13of40 4y agoFWIW, Google says 540 electrical deaths per year in Europe vs. 200 per year in the USA. Whether that's from lower voltage or more GFCI is anyone's guess.
- xxpor 4y agoAFCIs aren't meant to protect against electrocution, just sparking which leads to a fire.
- jly 4y agoI'm not sure where you are getting this. According to the CPSC, who analyzed some 10s of thousands of fires, something like 50% of them were caused by wire arcing that could be prevented with AFCI breakers. This is the exact reason why the NFPA is moving the NEC towards eventually requiring AFCI on every circuit in the house.
- anikom15 4y agoKey word is could. Do AFCIs actually do their prescribed function effectively?
- Avamander 4y agoThey highlight bad appliance design especially hard, while also being somewhat difficult to pinpoint due to the design of many electrical systems. Arc detection is also basically somewhat complex RF processing, so there are multiple approaches to it and implementations vary. Plus (detected) arcs are common with for example brushed motors. Maybe there's something else the person you replied to would like to highlight, but I wouldn't call them a money grab, just made difficult due to some past choices.
- idiotsecant 4y agoGFCIs have a simple and well defined function. What is the current through one lead? What is the current through the other lead? Do they differ by more than x amount? If so, trip. AFCIs are a whole different thing - the plug is trying to predict when arcing is happening somewhere downstream of it and it has very little in the way of 'processing' power to do it, so generally there is a classical filter that is designed to detect the characteristic harmonics of the current waveform that are inherent to an arcing condition. When you experience a sharp upward or downward step in power draw you introduce harmonics, when you have capacitive coupling between SMPS you introduce harmonics, motors often introduce harmonics, etc. There's like a zillion things that can create AFCI trip conditions and cause spurious trips and frustration for users, and there's very few documented cases of them doing the thing they're supposed to do. I think it's a case of someone being well intentioned but releasing regulatory guidance to use a product that isn't quite there in terms of technology maturity.
- StrictDabbler 4y agoAFCIs are just The Man trying to stop us running Tesla coils.
- simeonf 4y agoAgreed on AFCI circuit breakers! They are now mandatory for all 15-20 amp light and plug circuits on new construction where I live - although breakers for large appliances do not require them. But I have several portable tools (eg a carpet cleaner) which will make an AFCI breaker trip every time. AFCI circuit breakers seem to be more fragile (read the box: much smaller range of acceptable heat and limited number of duty cycles) - I apparently killed one just by tripping it repeatedly. And while a regular 15 amp breaker is a few bucks, the CAFCI breaker I'm supposed to use is $45...