Well, it's rare that Brian and I completely agree on anything (almost as rare as non-polarized line cords ;-) but he's summed it up perfectly.
Just to be sure, I'd double check with a meter that the switch contacts are indeed the two silver pins (1 & 2); connecting the line across those would not be a good idea. Just curious: where'd you get that cord? Aside from items that have an isolating transformer, non-polarized cords and double-insulation seem to be becoming more and more common on small appliances that used to have three-prong grounded cords. That supply looks gorgeous by the way! m On Fri, Dec 9, 2022 at 8:32 PM Spencer <spencer...@yahoo.com> wrote: > I've included a few pics. I thought i had it figured out, but maybe not. I > actually haven't put on a new AC rocker yet - still waiting on them. Here's > the link => 10x SPST Red Neon Light On/Off Round Rocker Switch 6A/250V > 10A/125V AC | eBay <https://www.ebay.com/itm/274361807522> > > This project has really turned out well, and I don't want to kill it > wiring the rocker wrong!! The pics do show both blades are the same so my > eyes tell me, but they've been wrong before. > > Let me know what you think of the pics. > > Thanks > > Spencer > > > > On Friday, December 9, 2022 at 07:35:20 PM EST, Mike Stein < > mhs.st...@gmail.com> wrote: > > > Glad you got it sorted. > > BTW, not that it matters much in your application but I'd be surprised if > that cord were not polarized. Most cords like that are, and yours looks > like it has a ridge on one side that denotes the neutral (some cords use a > white stripe). Are you sure that one blade of the plug isn't wider than the > other so it can only plug in one way? > > It's not a matter of plus or minus but of safety; on a lamp for instance > where you can touch the threaded part while changing a bulb you want to be > sure that it's connected to ground and not the 115+ volt hot 'line' side > and that the switch turns off the 115V and not the grounded 'neutral'. > > m > > > > On Fri, Dec 9, 2022 at 3:04 PM Spencer <spencer...@yahoo.com> wrote: > > Hello Brian. > > It's a SPST 3 position switch. Link ==> 10x SPST Red Neon Light On/Off > Round Rocker Switch 6A/250V 10A/125V AC | eBay > <https://www.ebay.com/itm/274361807522> > > > > > Been busy - darn gum surgery. Not fun ;-( > > > On Tuesday, December 6, 2022 at 07:16:09 PM EST, Brian K. White < > b.kenyo...@gmail.com> wrote: > > > If the plug is not polarized then there is no hot or neutral. > > One wire IS hot (swings from -120v to +120v relative to GND). > And one wire IS neutral (stays at 0v relative to GND). > > Relative to each other, it's the same 120vac either direction, or > rather, there is no such thing as a direction. > > But if the plug is not polarized then you have to treat both wires as > equally hot, since every time it's plugged in either side could be the > hot side that time, at random. > > Switches come in all kinds of arrangements, so the only way to know how > to wire this particular switch is to test it with a continuity tester > and observe what connections it makes in each position, or consult it's > datasheet. Sometimes there is a diagram of the connections drawn right > on the body, otherwise google it's model number or find the datasheet > from the website where you got it or perhaps it's packaging. > > A rocker with 3 pins and 2 positions (you didn't say how many positions > btw so I'm assuming) is fairly likely to be a center-common SPDT on-on, > hopefully non-shorting (break-before-make). Meaning the center pin is > connected to either one side or the other at any given time. When you're > turning one pin off, you're also turning the other pin on at the same > time. In this case since yoiu only care about turning something on/off, > you would just use the common pin and either one of the others. You just > run your hot wire from the wall to the center pin and connect the load > to either of the other pins, either one, doesn't matter, but only one, > and leave the other pin unconnected. (might want to cover it with > heat-shrink) > > Except that is just one common configuration and might not be right for > your switch. > > Really the switch could be totally different. It might have 3 positions > and be on-off-on, or the common pin might not be the center pin, or it > could be a lighted switch where only 2 pins are for switching and the > 3rd pin is to power the light, and that light may also possibly not take > the same voltage as what's passing through the main pins. > > Even a lighted switch where at least one of the pins is definitely > special and different, still doesn't necessarily have a right way to > wire it, since it's still up to you to decide when you want the light to > be on. Usually you want the light to reflect the power state, on when > the device is turned on. Or maybe you want the light to be a pilot light > that is on at all times so that you can find it in the dark, or so that > it indicates when power is available to the device rather than > indicating when the device is turned on. > > There is unlikely to be a particular pin for GND. It's possible if the > switch has a metal body, or for example light switches in walls, or if > it has a light it might have a specific gnd pin, but generally there is > no such thing as a gnd pin on a switch, they are just contacts which you > connect to whatever your application requires. The closest thing to a > right or wrong is a general rule that for a mains power switch would be > to switch the hot side rather than the neutral side, simply so that when > it's in the off position, the least amount of things are hot. > > But since you have a non-polarized plug, both wires are equally likely > to be hot at any given time, and so you just pick either one for the > switch, and treat the entire inside of the box as hot, and make sure the > whole box is well sealed and insulated, and users are well protected > from the internals. Or better, get rid of the non-polarized plug and use > a polarized one, and then you have an actual hot side to treat as the > hot side. > > -- > bkw > > On 12/5/22 21:52, Spencer wrote: > > Hello > > > > Got a wiring question. > > > > I built a simple 18VDC PS from JameCo and I put it in a project box. > > I've added two pots for adjusting power, banana plugs for external > > power, two mini voltmeters and will add a USB port for 5VDC. All this > > works but now I want to add a AC rocker. The above was simple except > > for the meticulous care that's needed to drill into a metal box. Now the > > next item I want to add is an AC rocker switch but I'm a bit unsure how. > > It's a 3 terminal AC rocker, and my understanding is the bronze terminal > > is ground, the center is the power source, and the 3rd one is > > accessory/load. What confuses me is the proper way to wire it. If the > > plug was polarized I wouldn't be confused. I've attached a photo of the > > back of the PS which shows the two power supply wires (one with writing > > and the other none). The videos I've seen doesn't explain which is > > power/live and which is ground using this type of wire. The plug isn't > > polarized so it's not easy for me to determine + from -. I put a meter > > to the wires inside the PS and it shows 119 and if I switch the probes > > it still shows 119. What I was expecting was to see -119 when the probes > > were wrong and this would've told me which is + and - but it didn't. So > > which wire goes to the power source terminal and which wire goes to the > > ground terminal? Do I simply wire it by wiring together the wires with > > writing and the wires without writing? I hope I've made sense. > > > > Thanks > > > > > > > > > > > -- > bkw > > >
