My impression is that almost everything the AFDDs have done for the electrical fire statistics in the US could have been done much more cheaply with blanket 30 mA RCD protection, provided all fixed wiring contains a CPC (ground wire). Unless you're talking K&T wiring, a series arc due to a poor connection will involve the CPC within a very short period of time as insulation breaks down from the heat and trip the RCD.
I've grown up with TT supplies and therefore whole-house RCDs, first 100, then 30 mA and consider them the cheapest form of electrical fire and life insurance. The only non-RCD supplies I've ever seen were ancient setups that used the city's mains water network as a giant earth electrode. This practice was legal until 2001 but despite the low earth impedance, RCDs were usually added as early as the mid-1960s.
Very much so- early AFCIs had 30/50ma GFP protection built in which caught frequent code violations and damage to NM during rough in. In the last 10 years several manufacturers have taken it out- ironically over wiring errors causing nuisance tripping.
The CPSC's original concern regarding cords could have been met with fuses built into the cord cap. The level of protection would have been higher- AFCIs stop looking for parallel arcs below 75 amps. This value was based on the lowest anticipated short circuit levels in building wiring. However, beyond that at the zip cord level it is possible for short circuit levels to drop below 75 amps.
