electrical switchs talk thread

Discussion in 'General Electronics Chat' started by Mathematics!, Dec 4, 2013.

  1. Mathematics!

    Thread Starter Senior Member

    Jul 21, 2008
    With electronics it was common to have SPST , SPDT , DPST , SPDT, (in theory you could have more poles / throws in electronics but in practice building home electric circuits those are the only 4 I ever came across in stores for. Other then maybe dimmer switchs which is more of a continuous throw based switch. And once I saw a 3 throw based switch the center was off state

    SPST (is just regular on and off switches )
    SPDT ( are standard 3 and 4 way switches used for controling an object at multiple locations pretty standard uses 14/3 red/black combo ..etc)
    DPST ( is like a 2 regular on and off switch so you can control 2 different circuit on the same switch at the same time for instances)
    DPDP ( are like a 2 regular 3 /4way switches builtin analogy would be from the SPST to DPST )
    Curious I have looked for switches for 240 volt applications but I only see the 120volt rating on label. I know some switches are rated
    for 15amp or 20 amp. But I am wondering do they make 240volt ones or are the ones that say 120 good also to uses on 240. I would assume so but I don't see much of these at stores like home depot. Probably not used often enough maybe. Or maybe the electrical supply stores would care more of a selection.

    Note: Of course they have kill switches and other switches for higher voltage but I am talking for residential house building. I normally only see SPST , SPDT (3/4way switches). Are there any others that they usually uses in homes or is it basically those 2 types with maybe dimmer switches as well.

    I don't know how common it is to uses a DPST to control 2 lights/appliances on separate circuits in home/residential application.
    What I am getting at is in theory knowing the inner workings of the different switch types allows you to open up new worlds in designing circuits in a house but in practice (and under the house codes ) how often does one use the other types of switches (other then the on/off , 3 , or 4 way switches )

    Also it seems to me that one could if he wanted to get the same 3/4way switch effect by using more 2 way switches
    and 14/3 or 14/4 wiring in creative ways. So one would not need the 3/4 way switches ever if he want to .. obviously for conveniences because one could build the built-in circuit of the 3/4 way switch it self into his circuit using 2 way. But I have to say the 3/4 way switches make it easy to rig up or much more easy.

    I know I repeated myself on this thread a lot but I am curious how often the professionals uses types of switches in homes. Also if there is any difference when it comes to the commercial/industrial building other then higher rated wire/switches maybe (i.e is it the same types of switches just higher rated or is it completely different)
    Last edited: Dec 4, 2013
  2. studiot

    AAC Fanatic!

    Nov 9, 2007
    I am not sure what your issue is in the entire thread, but the above paragraph seems confused.

    For lighting circuits where you want to switch from two positions you use two way switches.
    If you want to switch from more than two positions you still use two way switches, but wire them up as what are known as intermediate 'switches'. That allows you to switch from 3 or more positions.
    So it is the wiring configuration that permits this, not the switches.


    One application that you might wish to have a 3 way switch from one position would be to control the speed for some extractor fans. Special 3 way switches are availble for these.

    Last edited: Dec 4, 2013
  3. Mathematics!

    Thread Starter Senior Member

    Jul 21, 2008
    No your not getting it ...
    3/4 way switches aren't the issue here it is know how often the different types of switches are installed in home and other buildings.

    Is it really only those few types of switches used most of the time or is there a lot more types of switches uses ?
  4. inwo

    Well-Known Member

    Nov 7, 2013
    I wired houses for 20 years in the 60s and 70s.
    Never used switches other than 3way, single pole, and rarely 4way.

    Double pole are required for switching 240vac when there is an off position. As in an electric heat thermostat. Or in gas stations to pumps.

    A selector switch might be used in an exhaust fan. Single pole 3 or 4 position.

    Momentary switches were a fad for a while with low voltage lighting control. And doorbells of course.

    What else is there to switch?:confused:
  5. GopherT

    AAC Fanatic!

    Nov 23, 2012
    In our warehouse with 480 volt lighting, we have standard 120 volt switches that activate relays to turn the lighting on/off. For direct switching, the panels look more like fuse boxes with a big lever ion them.

    The switches you listed are about the only formats that are needed unless you get into some 6 position rotary switches. 4 position slide switches (single, double or triple throw). Each of those are more like panel or selector switches, not power switches.
  6. MaxHeadRoom


    Jul 18, 2013
    As GopherT mentions, factories and industrial buildings that have banks of high voltage Mercury vapour or HP Sodium lighting etc, have ordinary SPST switches that operate relay or contactor banks for switching.
    Anything more complex is usually done with some device such as a PLC or on a smaller scale a Smart Relay.
    Domestic installations are pretty basic.
    Curious as to why the question?
    Last edited: Dec 5, 2013
  7. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    There isn't a single switch in the building I work in. Its all just run back to the breaker panel.. When we leave we shut off 3 breakers that turn off the 40+ metal halide high bay fixtures. 2 for the warehouse area and 1 for all the lights in the front office area.
  8. bertus


    Apr 5, 2008