-------- In message <586a8b40.4050...@erols.com>, Chuck Harris writes:
>Back in the dark ages of ~220V electrical distribution systems in >Europe, the reaping due to unintentional grounding of a ~220V wire >was so common and extreme, whole house ground fault interrupters >were mandated for all residential/small business power systems >therein. Close, but no cigar. The main problem was that in many countries outlets did not have a protective ground terminal. That meant that an internal fault in your appliance had a 50/50 chance of lighting up some exterior metal part you could touch. The "obvious solution" isn't obvious in countries where the geography does not allow you to obtain proper "protective ground". Norway being a good example. But even countries with the "obvious solution" of protective ground in all outlets saw problems, because it took 10-16 ampere misdirected current to blow the fuse, and you can light most flameable stuff with a lot less energy than that. The "Residual Current Device" solved both problems. RCD's even protect you from internal faults where proper protective ground is not available, by providing neutral from "outside" the RCD as PG in the installation. You'll still be (horribly!) exposed of an accident in the distribution grid (or lightning!) fires up the neutral, but that's simply life - or death - without a grounding rod. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.