EE question: A DPST switch, a neon lamp, and a resistor walk into a bar...

[626Pilot]

I'm building a custom "IEC box" (IEC plug, breaker, and switch) for a 3D printer, which I will release on Thingiverse when I'm done messing with it:

I got an illuminated 120VAC DPST switch. It has four pins on the back:

Inside, there are two contactors, one for each side:

Sitting on top of the contactors is a pair of round metal pins:

Those pins connect to a neon lamp, and a resistor:

I'm having trouble getting the bulb to light without any white smoke appearing. Here are the combinations I've tried:

• Load wired to both left pins, or both right pins: Current passed, no illumination
• Load wired to top pin on one side, and bottom pin on other side: No (or very little) current passed, but the bulb lights up
• Load wired to pins on one side, with each pin jumped to its neighbor: Loud popping sounds, white smoke, bad smell

The switch was designed as a replacement for some standard thing that would be plugged into a panel, and comes with zero documentation. I haven't had much luck searching online, either. How do I wire this so that it lights up, while passing current? I have an idea to try connecting the load on one side, and then neutral on one of the pins on the other side, but I only got two of these switches and I don't want to burn the second one.

[nebbian]

I got an illuminated 120VAC DPST switch. It has four pins on the back:
pins.jpg

Power IN and neutral IN to the top two pins, load OUT and neutral OUT to the middle two pins.

[626Pilot]

That makes perfect sense. The switch isolates the equipment from both the hot and neutral sides of the circuit, and the lamp's internal pins sitting on the load side of the circuit makes it only light up when the switch is on. I previously thought they used four pins because the form factor was convenient. Thank you!

[dc42]

You can simplify the wiring if you use an IEC inlet with the illuminated switch and the fuse built in, e.g. http://www.ebay.co.uk/itm/3-Pin-IEC320- ... 1606853034.

[Eric]

You can simplify the wiring if you use an IEC inlet with the illuminated switch and the fuse built in, e.g. http://www.ebay.co.uk/itm/3-Pin-IEC320- ... 1606853034.

Not much simpler on the wiring, as it only eliminates one wire going to the fuse. The switch is electrically independant and still has to be wired correctly. However, it does mean there isn't too much demand for a printed switch/fuse/socket box.

[626Pilot]

My "holy grail" was to get a 350w power supply in a "brick" form factor, with all the IEC crap built in, but no one seems to sell those.