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 > > >
