Power plug with 3 prong switch wiring

I feel like I’m going crazy… Everyone with this plug seems to have 4 prongs in the switch part… The only place I could find with someone using 3 pronged one, he skips the 3rd!

I just need some help with how exactly I need to wire this plug…

[attachment file=86340]

Assuming standard color conventions, i.e., black is hot (line), white is neutral, and green is ground, here’s what you’d do:

  1. Check continuity of the terminals (input to output) with the switch in the energized/on position to figure out which input terminal is connected to which output terminal.
  2. Inputs:
    1. Wire black to the input terminal connected to "1"
    2. Wire white to the input terminal connected to "2"
    3. Wire green to the input terminal connected to "3"
  3. Outputs:
    1. Wire black to "1"
    2. Wire black to "2"
    3. Wire black to "3"
[attachment file="switch wiring.JPG"]

No, you have to wire in the switch.

Ground is still ground, Hot goes through the switch, neutral is straight through.

Ok, that makes sense, but again, that skips the 3rd prong on the switch…

the switch has two states off and on. When it is off then the center terminal is connected to the other prong on the switch. it is a Single Pole Double Throw (SPDT).


OOOOKkkk. That makes more sense now.

so switch side…

  1. brass is empty
  2. gets my black wire
  3. gets a jumper to...
plug side...
  1. jumper
  2. gets my white wire
  3. gets my green wire.
ok. explained like that with the 2 state switch, makes much more sense now. Thank you both.

Doh! That’s what I get for assuming things. Thanks to Ryan for fixing my assumption!

It is my humble opinion that the wiring above (2 red wires) is incorrect. The jumper from the load out from the fuse should go to the center position on the switch. If you want the switch to light when powered the bronze terminal (3) should be connected to Neutral (Not ground). I have attached to photos to back up my opinion.You must look close to see the numbers on the switch photo.

[attachment file=“Screen Shot 2019-02-11 at 3.37.38 PM.png”]
[attachment file=“Screen Shot 2019-02-11 at 3.36.50 PM.png”]



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Issues with posts disappearing and uploading images. Trying again.

IEC320 C14 250V Fuse Inlet Male Power Supply Connector w Rocker Switch - Wiring Diagram


Awesome! Thank you so much. I will link that and your site ASAP.

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Just a FYI, you need to connect the neutral to the power supply too. :slight_smile: Also the light turns on with power even it you swap the red wires at the switch, I was looking at resoldering the thing when I just tried it and it worked. Love the fuse.


And the terminals on these work great with insulated crimp female spade connectors.

So, after a couple of months, had a bit of drama with this, was cutting something and everything died on me. Bit of an oh shit! moment, but turns out the fuse was OK, but the connection on the far end of the fuse to the wires was the problem. So, good news, I can still use the fuse, but can’t use the switch. Will have to go with something beefier methinks, no doubt user error, but it probably needs a smaller fuse. The rest of the stuff works fine, rasp pi, mini rambo, steppers, etc, and the fuse, my favourite part.



Bought another one with the wires done already, so follow the order in the pic.

powerswitchholder.gcode (6.2 KB) For a plank of 3/4" (19.05 mm) wood, it cuts off the end at 200 mm.

This was the perfect thread to find at this very moment. Thank you!