DIYbanter - View Single Post - Advice please - 3 way light switches

In article . com,
says...

Keith Williams wrote:
In article ,
says...

#1 "up" & #2 "up" = off. Otherwise SPST switches would work (and
you coudn't turn the light both on and off from either end).

S #1 "up" S #2 "down"
S #1 "down" S #2 "up"

or Switch #2 "

A switch circut with two spdt switches has two on states,
and two off states. I like them set up so the
light is on whenever the two switches are in the same
position.

Certainly, but Larry had three "on" states and only one "off" state
(which could be done with parallel SPST switches). "Three-way"
certainly is a curious terminology.

--
Keith
Well like this guy says:
".. it has to do with the number of "drop points" and not the number of
switches in the circuit. You see back in the early days of electrical
wiring, back in the days of Thomas Edison, the vocation of
"electrician" was brand new. These new electricians would base their
cost estimates partly on the number of "drop points" on each circuit. A
drop point could be a switch, a load or any junction point. In a sense
a circuit with only 1 switch and 1 load would be a "2-way". I suppose
this was because the wires had to go "two different ways". A circuit
with 2 switches and 1 load would be "3-way". Incidentally, a circuit
with 1 switch and 2 loads would also be a 3-way, but over the years,
the label of "3-way" has evolved into meaning any circuit with 2
switches in it."

I guess that's about as good of an explanation as I've heard.

That explains it to me, but it still seems illogical.

....then there's "4 way".

I was going to bring that up but thought better. ;-)

--
Keith