The above Ad will no longer appear after you Sign Up for Free!

switches/ screw terminal vs. dimmer/leads

Discussion in 'Lighting and Electrics' started by chrizEHS, Apr 19, 2007.

  1. chrizEHS

    chrizEHS Member

    Messages:
    18
    Likes Received:
    0
    ~Disclaimer-Completely random question~

    why do switches have screw terminals and dimmers have leads?

    -let me clarify that - I am talking about Home-Depot-at-5-$-a-pop type stuff here. Just a basic unit of both kinds of units. I just noticed that and i figured it would be cool to understand why. soory if this seems like a stupid post, after people are like talking source 4 revs and stuff.

    thanks

    chris(z)
     
  2. Edrick

    Edrick Well-Known Member Premium Member

    Messages:
    1,314
    Likes Received:
    35
    Location:
    Boston, MA
    I've seen plenty of dimmers with terminals, I think the reasoning some dimmers have leads is because the housing is too big to fit it inside of a standard 1 switch box with terminals on the side. But that's only an educated guess.
     
  3. JSFox

    JSFox Active Member

    Messages:
    141
    Likes Received:
    4
    Location:
    The Tundra
    It's a simple cost of mfr'g issue. Switches are mechanical devices and the least expensive way to allow a connection is to just extend the mechanical elements out to screw terminals. Dimmers are electronic with a Triac (or dual SCR's in more expensive ones) used to do the actual voltage control. Since something needs to be soldered to either a circuit board or directly to the triac anyway (thus not cost diff between terminals or wire) and then wire is less expensive than a screw terminal.
     
  4. ship

    ship Senior Team Emeritus Premium Member

    Messages:
    6,069
    Likes Received:
    364
    Location:
    Illinois
    Such questions are not stupid - it instead shows a very curious nature to understanding what you deal with and how it works or more important why.

    In expanding upon the posts, some of the higher wattage commercial dimmers I also believe had screw terminals. For the most part however, your observation is correct. Time as with JSFox's post to crack a dimmer and switch open in seeing why it's a wire verses a screw terminal. The wire most often leads to a circuit board on the dimmer. It would be a bit difficult to make the plate of a screw terminal lead to a circuit board. On the other hand, inside a switch, it's a mechanical donnect or disconnect by way of plates that are bent between the contact point of the screw terminal and that of the switch. Adding a wire to this would also be at least less cost effective to do.

    In a nutshell, this economics in easy to do by way of circuit board connection verses flat plate connection might be the key reason for your question.
     
  5. astrotechie

    astrotechie Member

    Messages:
    64
    Likes Received:
    0
    Location:
    Woburn, MA
    hold on, there is a difference. I have never noticed a difference. But then i have changed a dimmer in a long time.
     
  6. chrizEHS

    chrizEHS Member

    Messages:
    18
    Likes Received:
    0
    ok guys, that makes perfect sense, When you reason it out, mechanical-screw, electronic-leads....

    Thanks guys

    C. whitman

    p.s. to ship- I have been trying to read you posts whenever I have some spare time. VERY informative. thanks.
     
  7. Edrick

    Edrick Well-Known Member Premium Member

    Messages:
    1,314
    Likes Received:
    35
    Location:
    Boston, MA
    Going back to my Origional post, about why I thought it was that way (which is incorrect), I'm going to be picking up 4 Lutron Dimmers to fit into a 4 switch box for my basement. So that's going to be fun to fit everything in to that box it's already crammed as it is with the current dimmers. I think the Lutron ones use screw on terminals but i'm not sure.
     
  8. JSFox

    JSFox Active Member

    Messages:
    141
    Likes Received:
    4
    Location:
    The Tundra
    Be careful. Dimmers create a lot of heat and even 2 in a 2-gang box can lead to premature failure. With 4 you could be asking for routine replacement. Talk to someone at an electrical supply house or an electrician and make sure that with the wattage you have planned you'll be able to disipate the heat. You might consider using remote dimmers with X10, CEBUS, or similar control. Smarthome.com has some of these.
     
    Last edited: Apr 22, 2007
  9. Van

    Van CBMod CB Mods Premium Member

    Messages:
    5,753
    Likes Received:
    1,039
    Occupation:
    Project Manager, Stagecraft Industries, Inc.
    Location:
    Portland, Or.
    That's good advice. Another thought is that some companies manufacture a heat sink that attaches on the front in the place of a cover plate.
     
  10. soundman

    soundman Well-Known Member

    Messages:
    1,084
    Likes Received:
    113
    Location:
    Nashville TN

    There is more than just guessing at this, there is an answer to how much you can have in one J box. each J box is rated for its size in cubic inches and there is a chart in the NEC ( Code Tables 314.16(A) ) that spells it all out.

    Here is a site that might clean things up.
    http://bg.ecmweb.com/ar/electric_box_box_box/index.htm
     

Share This Page