23 Nov
2014
23 Nov
'14
12:53 p.m.
Chuck Guzis wrote:
On 11/23/2014 07:24 AM, Holm Tiffe wrote:
Yes, yes.. Edison 27 Sockets aren't really unknown here and still in use
today. As for History, think about old German Names like Siemens or AEG.
We had such old Power distribution systems until the fifties I think, there
where even DC Supplies or "two phase" 2x110V with the center connected to
ground in use.
But this gets standardized to times where people mostly had nothing other
than light bulbs, irons or tube radios at home so the "collateral damadge"
was small...
Can't see any advantage of the american system
to the german, sorry.
Frome here it looks pretty outdated.
Well, that's what evolution sometimes gets you. The US 3-wire
residential distribution system dates from Edison's 1882 DC system
(+100,0,-100). One of Edison's original carbon-filament lamps will
screw into any modern residential lamp socket. There are homes in the
US still using knob-and-tube wiring, as well as Edison-base fuses in the
distribution box. Originally, residential distribution was intended for
lighting only, so AC versus DC was not an important concern for the
average homeowner. 100V (plus a certain amount for line drop) was
selected because it was felt not to be a significant electrocution hazard.
Although the NEC dates back to 1897, it never has been the sole
governing standard in the USA. For example, in the city were I was
raised, non-metallic-sheathed cable was illegal; Rigid conduit was the
rule. Kept the very strong IBEW in control, it did.
Remember to have seen such tubes with two wires in some sort of tar for
isolation when I was a kid.. I'm 51 years now.
When I worked in a steel mill, the distribution panel in our small 4-man
shop looked like 460V, 230V, 115V 60Hz AC, 440V, 110V, 220V 25Hz AC and
250V DC, all with accompanying transformers. Larger shops included
3-phase distribution of both 25Hz and 60Hz.
OMG.
The point is, that the US has adopted a course of compatibility with
older standards, rather than a revolutionary course.
Do you think that this was a good decision?
I understand that parts of Europe were also slow to abandon DC
residential lighting.
--Chuck
As I already wrote, at least in east germany (behind the iron curtain)
this changed in the fifties and that where installations from before ww2.
Regards,
Holm
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