Wire Up a Fused AC Male Power Socket

I've been using these cheap AC Male Power Sockets from Amazon and Ebay for a number of my projects. They are easy to incorporate into my electronic enclosures, and they provide both a switch and fuse for whatever load. Unfortunately, no wiring diagram or instructions are provided with these units. Several sources on the internet discuss how to wire these [1,2], although the knowledge is a bit scattered. My attempt here is to put all of this knowledge into one place as well and discuss safety and offer suggestions for mounting the unit into your enclosure.

Note: images courtesy of [3].

[1] https://www.amazon.com/review/RD487YB8O446U/ref=c...

[2] http://www.electro-tech-online.com/general-electronics-chat/122625-help-wiring-up-iec320-c14-socket.html

[3] https://www.amazon.com/gp/product/B0050HH70E/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Step 1: Warning!

Before starting on this project, you need to be aware of related electrical hazards and how to keep yourself safe. 120V AC can lead to fires and, although not commonly, kill.

1. Always disconnect (not just turn off) your unit from the wall before getting anywhere near the electrodes or other exposed wires.
2. Make sure no electrodes are exposed. Anything dangerous should always be enclosed or shielded with electrical tape, electrical terminals, etc.
3. Always use a fuse with this device. In addition, make sure you size the fuse for your application. Check the power load of your desired device to determine your fuse size. Amps (current) = Power (watts) / volts. If uncertain, err on having smaller fuse that you need. If it repeatedly blows under normal operation, slowly increment up until the fuse stops blowing. Never go any higher than you absolutely have to.
4. Use the correct wire size. The unit is rated for 10 A, and it is recommended that you use 12 gauge wire at 10 A. Smaller power/current requirements means to you get away with smaller diameter wire. There are plenty of tables on the internet to tell you which wire gauge to use for any current.
5. Always connect the ground between your two sockets. If you're using a metal enclosure for this project (which is safer than plastic), make sure connect it directly to ground.

Step 2: Understand the Diagrams

Before wiring up the socket, you should take a minute to understand its circuit diagram. Power connects to the front, and the exposed electrodes are on the back. A fuse connects the "unfused hot" to the "fused hot" section on the back (see image). The fuse is internal to the enclosure and can be accessed from the front.

To incorporate the switch into the circuit, two jumpers need to connect the left-most electrodes to the switch. Notice that the switch has two sets of electrodes, the narrower set and the wider set. The jumpers should connect the socket electrodes to the narrow set in order for the LED in the switch to work. Polarity shouldn't matter. Wires connected to the wide set of electrodes, in addition to the ground, continue on to your load.

(Edit thanks to dave-46): Note that the wire colors specified in my diagram is specific to United State 120V wiring code. If you live in another country, your colors may likely be different.

Step 3: Wiring

As far as wiring, I recommend either soldering (for permanent installation) or crimp terminals (for ease of maintenance). Using the diagram on the previous section, make the correct connections. As previously discussed, make sure you use the correct wire gauge.

Edit: In the pictures above, I'm using 12 gauge wire as I want this unit to safely handle 10amps.

Step 4: Mounting

Please see the attached diagram and CAD files for mounting hole dimensions for the socket. Units are in inches. Most of my enclosures are laser cut, and I use this same CAD files when cutting the mounting holes. Dremel or other cutting tools will work just as well. If using one of these methods, print out the cad file to scale on a sheet of paper, trim and tape it to whatever surface, and drill and cut along the lines. M3 or 4-40 screws are the ideal size for the screw holes.

Good luck!

Comments

[Jonathanhaar]

Thank you so much. The three prong wiring was obvious and I knew I had to jump to the switch, but my guess would have been wrong. You spared me bugging two of my EE friends!

[psxp]

thanks for posting this. It was helpful to get it wired up correctly and the way I wanted it. For the light in switch to light when power is on.

[Marianolvr]

Amazing and concise tutorial. Thank you!

[crs48]

I have a follow-up question. I recently purchased a power switch, but rather than 4 prongs at the switch, there are only 3. How would I wire this up?

[jwbrooks0]

Hmm. Do you have a picture?

[doug_scott]

I have a 3 wire one as well, here is a pic I hope. BTW, the 3 prong (total of 6 connections) come on the push-in rectangular shape with top corners at 45 degrees. I am a retired auto mechanic, DC circuits don't give me any issues, but this AC stuff just confuses the hell out of me. For example, if AC current flow is alternating directions, how does it get anywhere?
If you could help me with where to connect both ends of the wire it would be greatly appreciated. My 3d printer power supply has three connections, marked a N, L, and Ground.

[crs48]

I do, but I am having a hard time attaching it to a comment. I'm not used to a Mac. LOL

[voxelman]

I noticed that you made all of your connections with white wire. It is generally good practice to use the same color wire as the incoming leads for the extended connections. As you have shown for the US: Green for Ground, Black for Hot and White for Neutral. This minimizes confusion when making the final connections to the load. Otherwise, Great Instructable!

[jwbrooks0]

Haha. Yeah. If I had those colors in that gauge wire, I would have used them.

[psxp]

Tip : If anyone is wiring up a power bar, cut off the existing plug, then also maybe a few inches of the wire.. then you will have the same coloured wires to use in the plug. simple

[RichD35]

Hello. I was looking on the AWG current ratings chart and noticed that 12 AWG at 43 strands or more handles 10 Amps. Are you using stranded wire? I have some single core 20 AWG for a power supply that will pull 4.2 Amp and I was confused as to why you chose 12 AWG. I didn't see anywhere that you used stranded so I just wanted to be sure. Look forward to your response!

[LucaC100]

I connected mine EXACLY AS SHOWN. Guess what? IT DOES NOT WORK - The LIGHT stays ALWAYS ON (even when switched off). Pretty useless. The designer was surely drunk (or on drugs).

-------------------------------------------------------------------------------------------------------------------------------------

UPDATE: ... till I read "The jumpers should connect the socket
electrodes to the narrow set in order for the LED in the switch to
work."

Now, it turn out that mine had the switch mounted "backwards", so I didn't connect the NARROW contacts, but the FAR ones.

Now I'm going to desolder everything, pop out the switch, turn it 180°, pop it back in and retry.

-------------------------------------------------------------------------------------------------------------------------------------

UPDATE: Turning the switch 180° worked perfectly!!

Now the LED turns on only when the switch in the ON position and will light off

when the switch is OFF.

Thank you!

[jwbrooks0]

Glad you got it sorted =)

The other easy way to think about this orientation is the location of the LED. You can see the leads for it on the back of switch, and the switch can ONLY turn on AND off if the power is on the downstream side.

[blaklite]

Excellent guide, unfortunately I found it only after piecing together most of the info I needed.

However there is one issue that I still cannot find a definite answer for.

!!! ?? What type of fuse do you use for these ?? !!!

Here in the UK a "BS1362" plug fuse is 1" by 1/4' (approx 6mm by 24mm), which means nearly all of the "normal" mains fuses you find are the same diameter, but a little too long for these sockets =(

What I have pieced together is that you need something akin to an "internal" fuse. The same diameter but only 20mm long. Most of which come in the glass type, which I do not want to use.

What should I be searching for when looking for a fuse for these sockets ?

[jwbrooks0]

Thanks for the feedback!

Also, good point. Many of the AC sockets come with a fuse, but I've also bought those without it. What you're looking for is 5x20 mm fuses. I recommend one of the assorted fuse kits from ebay as they are cheap and provide a nice variety.
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p4712.m570.l1313.TR4.TRC2.A0.H0.X5x20+mm+fuse.TRS0&_nkw=5x20+mm+fuse&_sacat=0

[jwbrooks0]

Bad grammar. Edit: What you're looking for "are" 5x20 mm fuses.

[blaklite]

I only need one of them.

=)

Only wish I knew that before I got the thing, realized I didn't have a fuse, went out to get locally, to find none would fit.

So lesson no 1, if you are ordering one, get the fuse(s) at the same time.

What I actually ended up doing was carving holes in each side and forcing a 5amp plug fuse down in the hole, wrapping it all in tape. At least I got to practice wiring it up before the new one arrives.

Thanks

[LucaC100]

Moreover, there's a "hidden room" in the fuse holder itself, which allows to slide in and store a spare fuse, just in case you blow up your currently connected one.

At least, in mine (sold/branded by TooGoo on Amazon) there is such a thing.

[thericeshield1]

I have one of these and wired it up exactly like yours, however I have a question. When the switch is off and its plugged into the wall and I measure the voltage, it reads 0.25V compared to 0V when it is disconnected from the wall. How come there is this small amount of voltage even when the switch is turned off?

[tdragovich]

Induced voltage? It seems like a small amount of voltage to be anything except that.