Power Supply Switches 115/230? for?

By acidosmosis
Jan 24, 2003
  1. On the back of psu's you have a switch, normally they are for 115/230... and normally set on 115. What is the switch used for? Why would you use it?
  2. Mictlantecuhtli

    Mictlantecuhtli TS Evangelist Posts: 4,345   +11

  3. Vehementi

    Vehementi TechSpot Paladin Posts: 2,704

    Also, in different houses your computer room may only be 115V, as mine is. Some places it's 230V, it depends on your house. Check your electrical diagram for your house, and see what voltage is supplied to the room you have your computer in. Phew for checking mine before leaving my brand new Enermax on 230V, as default. If you select the wrong voltage the capacitors will...I don't want to say explode...they'll mess up ;) Or so I've been told.
  4. palmboy5

    palmboy5 TS Rookie Posts: 71

    nothing happens so my HP...
    i switch it between the two whenever i get a chance, just bored...

    no exploding...
    no difference...
  5. Vehementi

    Vehementi TechSpot Paladin Posts: 2,704

    Your room is probably supplying 230V, with that it doesn't matter if it's 115 or 230V. That makes sense, dunno if it's true though...
  6. young&wild

    young&wild TechSpot Chancellor Posts: 993

    I think 115v through out the whole house. I mean 115v 60Hz AC is the standard in the US.
  7. StormBringer

    StormBringer TS Rookie Posts: 2,244

    Well, I don't know what kind of PSU you are using Veh, but according to the way most are designed, having it switched to 115v and using a 230v line would fry it. Now, switching to 230v while using a 115v line will normally not work because of the switching circuit. The circuit inside the PSU parallels the 115 into the PSU when set to operate on 115v, when set to operate at 230, it pushes the 230v straight into the PSU. This happens before it goes into the circuitry that rectifies and cleans up the signal to produce a DC output.

    Sorry if I din't explain that very well but I'd probably need a diagram to to better and I don't have one handy. I also don't know that they all work the same way, though all the ones I have worked on have worked on some variation of that design.
  8. Vehementi

    Vehementi TechSpot Paladin Posts: 2,704

    Do PSUs not include protection against things like that? Protection against an ***** selecting 115V when his house is 230V and making his PSU go boom? That doesn't make sense.
  9. young&wild

    young&wild TechSpot Chancellor Posts: 993

    Well, i have seen some devices with warnings about the consequences of switching to a wrong voltage.
  10. StormBringer

    StormBringer TS Rookie Posts: 2,244

    It is called a fuse, and yes, if the fuse works as it is designed then it "should" protect the PSU from the extra power but things don't always work like they are supposed to.
  11. acidosmosis

    acidosmosis TechSpot Chancellor Topic Starter Posts: 1,350

    Started a large convo I see lol. First reply answered my question :p Thanks guys heh
  12. Rick

    Rick TechSpot Staff Posts: 4,573   +65

    Most decent PSUs (if not all) protect against little things like this. While I agree with Storm in regard to "things dont always work like they are supposed to".. It should give you at least SOME peace of mind. :)

    Fuses have been known to burn though - Which is the reason we use electrical breakers instead of fuses in U.S homes now.
  13. Supra

    Supra TS Enthusiast Posts: 190

    On the box of my new enermax psu it has two little boxes labled 115v and the other 230v. The 115v box has a little sticker in it probably meaning it was made for 115v current but for some reason there is still a switch on the back for the two voltages. Any ideas why they would do that?
  14. young&wild

    young&wild TechSpot Chancellor Posts: 993

    Hmmm....they might be trying to cut down the cost of production of the PSU, the degree of seperation between 115v and 230 is just a switch IMO. This way it easy for the company and the consumers(those moving around frequently).
  15. StormBringer

    StormBringer TS Rookie Posts: 2,244

    That switch is there to either send a single line or two lines of voltage. As I explained before, 115v is sent on two lines that equal 320v. The 230v is sent on a single line. So whether you use 115 or 230, the primary is still getting 230v. As I was saying before, sending the 230v on 115v circuit would cause problems(not to mention the possibility of pain, fire, sparks, etc) because the 115v line parallels that voltage over two lines then adds them together when entering the primary.
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