Ok I read the study. Funny it mentions the 1969 code change that made equipment grounds larger, there was no science behind that code change that I can see. I would like to see us go with the Canadians on ECG sizing and just use NM-D cable.
As would I, the smaller EGC would save copper and it works well in Canada. I think the reasoning behind it might come from the code making panel being worried about hacksters useing the EGC as a neutral. They will do it anyway, might as well lessen the risk?
The study has some weak points like they used a 120V arc limited to SCCA of 100A or 12Kw in power, I can find receptacles with SCCA up to 900A or 108Kw arc potential almost everywhere.
It seems proven that the ONLY benifit from AFCI is from the RCD or Residual Current Device built into the breaker. What manufacturer has eliminated this?
I agree with the RCD making a positive difference. I know GE has taken out the GFCI/RCD part so their AFCIs will work on shared neutral circuits, however Im sure others may have done this as well. LINK:
http://www.geindustrial.com/publibr...TNR=Application and Technical|DET-719|generic
How about amending 210.12 to allow a RCD as an alternitive to AFCI protection? RCD's are used like the Metric system almost everywhere else the cost and research could be shared world wide rather than making somthing for a market as small as the North American.
I think GFCI/RCD on all circuits (except the dedicated ones serving furnaces and refrigerators) should be the alternative to AFCI. RCD solves more problems than an AFCI. I however think the RCD should be on the branch breakers, not on a main or sub pain feeding multiple branch circuits like in the UK.
The RCD's are Main and branch breakers like a GFCI breaker. The miliamp (ma) trip of the RCD depends on the breaker size and the type of protection required. A Mains breaker would have a 300ma setting where branch breakers would have 10ma to 30ma.
Here is a summary of the requirements
http://www.etci.ie/docs/ET214.pdf
And if we have such good protection now with AFCI what about eliminating 210.6 and allowing 230V to ground outlets in dwellings as long as the outlets are RCD or AFCI protected in the occupancies that need it?