I bought a Double pole switch. Why, I don't know. I looked in my trusty
electrical handbook and my copy of the 2007 NESC handbook (to most wasted
$65.00 I've ever spent) and nowhere is there a reference to a "Double Pole
Switch". So, what is a "Double Pole Switch" and what is it used for.
I've used many a single pole switch and a number of 3 way switches in my
time but this one's got me a bit baffled.
Since you don't seem to know what double pole switches can do, you may
also not know what "double throw" means either.
If that switch has six terminal screws on it, not counting a frame
ground screw, then it is a "double pole - double throw" switch, most
often used for multilocation switch control of a light or other load,
i.e when more than just the two switches provided by a "three way"
switch system are desired.
If it only has four terminal screws on it, than it's a "double pole -
single throw" switch, and others have already told you what it can be
Other than 240 volt applications, I can
think of one that we used in my church.
There was 1 exhaust fan for both the men
and womens washrooms. A double pole
switch in each washroom .... one pole
for the lights in that room and the second
pole for the fan. In essence, if either
room is occupied (the light is turned
fan will run. When lights in both rooms
are off, the fan will shut down. This
avoided using relays to accomplish the
Jeff Wisnia wrote:
another application would be if you had such a number of lights as to exceed
the capacity of one circuit, but you wanted them all on one switch. Two
separate circuits, one switch, many lights. perhaps a gym, or an
On Sun, 25 Mar 2007 14:38:57 -0400, "Joseph Meehan"
Well, a double-pull double-pole switch can be used as a crossover
switch in the middle of a multi-switch run. A single-pull
double-pole switch is used to turn off two things simultaneously,
or both legs of a 240V branch.
I've seen double-pole double throw (DPDT) switches used with DC
motors, that could run in either direction depending on polarity.
A "4-way" switch is logically (physically?) a DPDT switch with
opposite contacts internally connected, so it has this reversing
| - - | | |
| | |
--------+----O O--/ |
| | |
I used a little DPDT slide switch with my analog VOM, voltmeter, to
reverse the test leads. Made it very quick on the ohmmeter setting to
test diodes in both directions, to test capacitors by watching them
charge then discharge and charge again. Didn't do this until after
ran out of regular probe wire and was using speaker wire for my test
I put a blob of silicone sealant over the solder connections so I
wouldn't zap myself. 25 years, still fine.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.