Manual AC Power Controller




About: Just a mild mannered programmer by day and a wannabe evil mad genius by night.

I have 4 AC outlets in a wall electrical box mounted inside a PC case I have setup as a bench power supply. After actually using those outlets I found they didn't really work out where and how I have them mounted for how I have stuff on my bench, which is why I built this AC control panel.

With this instructable I will go through the steps I took to build this AC control panel. I took a few days and I'm not 100% sure I'd do this 100% the same way, but here goes. I do still need to get the covers.

The pictures shown here are of the completed box minus the covers (as stated earlier I still have to get those). I don't think I'll try to make them, They are available online from a number of sources.

The schematic shown is a simplified version of the circuit. It does not show the wire nuts I used to make some connections.

Of course with the outlets shown/used and my location, this controller is for use in the US or any country where 120 single phase power is used with these types of electrical devices, and as always you should know the safety hazards, dangers, and proper procedures / wiring specs needed for your local codes when wiring a device like this.

With that out of the way..........

Step 1: Prepping the Electrical Boxes

I did a test fit of the outlets and switches to see how much room I would have left if I cut the bottom section of the electrical boxes off. I wanted to have a single item that both the outlets and switches would be enclosed in when I was done and I wanted to make sure I had plenty of room to run the wires as needed when all was done.

I cut the nail brackets off both boxes, At the time I was thinking I would cut some wood and make a frame for this device, not sure if I will or not.

I used a basic dollar store hack saw blade holder and blade to cut the nail brackets off of both boxes.

I then drilled a hole in the bottom section that I wanted to remove from the box. I used a jigsaw to cut off the bottom section. I have a variable speed jigsaw and set it on it''s lowest setting and squeezed the trigger so that when I cut the plastic it caused the box to vibrate as little as possible. I used a jigsaw blade that is designed for metal, a lot of teeth per inch. I also found that clamping the box to my table saw also helped reduced the vibration. I'm sure I could have used the hack saw for this as well, but I wanted to see if I could get the jigsaw to cut the plastic without melting it, which is why I didn't use the table saw, I'm almost certain that would have melted the plastic. The jigsaw would give me a chance to see how things were going.

I used some rubber cement to glue the boxes together, not happy with that decision, I wanted to use some bolts but I didn't have any I thought would work and I was too lazy and it was too late to go out and get some. I thought about JB Weld which I was going to mix up on the RS blister pack card board but I don't have much luck with JB Weld

Step 2: Waiting for Glue to Dry

With the backs/bottoms cut off of each electrical box and applying the rubber cement to the backsides of each box and putting the boxes back t back, I placed the assembly with an open side face down. I placed the bottoms I cut off on top of the box so what ever I chose to use as weight would not cause the sides to fluctuate. The bottoms will also help distribute the weight evenly.

While the glue is drying, I did let it sit overnight. I collected the outlets and I removed the connecting tabs that connect both the hots of the outlets and both the neutrals of the outlets. These tabs allow only one wire to connect both outlets (one hot wire to both hot sides of the sockets, one neutral wire to both neutral sides of the sockets), but since I wanted only one of these outlets to be controlled by a switch I removed the tabs so each socket would be separated electrically. If I did this again I would only remove the tabs on the hot side. It would make wiring the neutral side much easier.

Step 3: Prepping for Wiring.

I have a lot of wires handy that go from project to project sometimes. The black cord was last being used as a simple short extension cord. It originally came with my shop vac. I have salvaged many a vacuum cleaners over the years especially for their long cords. I take the vacuum cleaners apart to the point where I keep any and all screws that are still in good shape, but I do not cut the cord of the vacuum cleaner. I remove the cord and the switch(es) by disconnecting them by their terminals. My shop vac now has a nice 15 foot cord on it (it gets used in many more places then just the workshop) That cord I used on the shop vac is from a previous vacuum that still had it's original terminals on it and worked on the shop vac without having to change the terminals.

The picture with the electrical cord with a metal jacket (shown on a backless chair) is another extension cord that I have not used in many years. Note the dangerous use of the clamps on the one end. Don't ask. nothing illegal but nothing safe either, no one was hurt when it was used, still seriously don't use a cord like this. The wire in this cord is 3 wire insulated, 16 gauge solid wire.

The picture with my hand in the modified electrical box, is just my lazy way of measuring how deep the switch side of the box will be to the back side of the outlets. I have at least 10 measuring tapes around the house but cannot find them when I need them of course.

Step 4: I Began the Wiring.

I could have done this while waiting for the glue to dry. But keep reading for some things I would do differently.

Get a pair of pliers (preferably linemens pliers, blue handled pliers shown in the pictures), philips screw driver, wire strippers, and possibly a flat screwdriver or I used a small crow bar to help convince a few wires to bend so they would wrap around the screw on the outlets. Didn't really have a problem with the switch screw terminals.

Since I removed the neutral tabs I had to make that connection with wire as I indicate in the picture that shows the back side of an outlet with 1 green, 1 white, and 2 black wires connected to it. I cut the individual pieces based on the length I measured with my hand, plus a couple of extra inches for the wire that will be bare and will wrap around the screw terminals. The ground (green) wires could have been longer and the neutral (white) wires would have gone from outlet to outlet and then to the white wire that gets connected to the ex extension cord.

If you follow the schematic from step one and you understand this kind of wiring you should be fine to get it wired. If not find an electrician.

I used 4 wire nuts but if you leave the tabs on the neutral side of the outlets you could do the wiring with 2 wire nuts.

Doing the wiring was the hardest part of this project for me, not knowing what needed to be connected, but I had to re-cut a couple of wires due to my sense of stinginess with my wire.

Things I would do differently:

1. again I should not have removed the neutral connecting tab on the outlets.

2. I got stingy with how much wire I was using.

3. If I wasn't trying to be stingy with the wire I could have done the wiring of the switches secured them to the electrical box and then wired the outlets.

4. Doing the outlet wiring with the switches wired and secured I suspect would have been easier then wiring the switches and outlets together and then stuffing the wired assembly into the box. I had to re-secure one of the wire nuts securing 4 hot (black wire in this case) wires twice.

5. I would and possibly may still use some nuts and bolts to connect the 2 electrical boxes together.

Once I was done with the wiring, I realized I needed to drill a hole and get an electrical box connector to secure and run the extension cord through to connect to this wire assembly (next step).

Step 5: Mounting Electrical Box Connector

This was supposed to be a simple drill a hole, shove the threaded part of the electrical box connector in the hole, use the nut that comes with the box connector to secure to the connector to the box and slip the wire though the and tighten the strain relief of the connector to the wire. Supposed to be that simple.......

Drilling the hole was easy, placement was bad. Not sure if it could have been positioned better due to the placement of everything and not wanting to shorten anything out.

The hole was drilled with a 3/4 inch paddle bit. The hole was tight enough that I had to twist the connector in the hole as if the hole was threaded, and the connector was tight that way. But I wasn't really happy that I could not get the connector's nut on the threads. I got the rubber cement out again and used that very much like an RTV adhesive.

After this was in place and the glue was dried (another day of waiting). I shoved the wiring assembly into the box, (very much reminded me of the Chinese finger puzzles) ran the wires of the black extension cord in through the box connector and then saw that the insulation around the extension cord wire was not thick enough for the strain relief of the box connector to hold the wire securely. grrrr. I got a roll of my black electrical tape and just wrapped a bunch of it around the wire where the wire is secured by the strain relief part of the connector.

Once my extension cord was hooked up to the proper wires, in this case, green to green, white to white, and black to black. I secured the outlets and switches to the box for the last time.

This is when you should add the covers to each side of the box.

I made sure all the switches were in the off position and then plugged it in and tested it.

Step 6: Testing.....

With my 120 VAC outlet polarity tester, in hand I plugged in the AC power controller. The outlets closest to the camera are the unswitched outlets but are still controlled by the master switch.

There is a picture of the tester in each outlet showing the tester with both yellow lights on and the red light off. This means the polarity is correct for these outlets. It matches my outlets in my home as well.

The remaining pictures show the master switch always in the on position and the outlet switches are shown in both their off and then on positions showing the lights on the tester are off and then correct (respectively) for each outlet and switch position.

Hook up your AC devices and use it.



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    10 Discussions


    3 years ago

    Use PVC sprinkler pipe glue to join mains boxes together. Coat the edges to be joined, clamp in place, and allow the glued-up box to sit overnight before continuing work on the project.

    1 reply

    3 years ago

    Yes, Great Controller Design! If you replace the switches with relays, you could make a Christmas Lights Controller!

    3 replies

    Reply 3 years ago

    thanks! and yes it should be easy enough to convert this design to a relay based system, but somebody just did that instructable. ; )


    Reply 3 years ago

    What Instructable was that? Would you mind sharing the link, or the title name? Thanks!


    Reply 3 years ago


    3 years ago

    interesting project. What do you plan to control with it?

    I agree with your points on what to do differently. I feel you made this the hard way. it would have been much easier to install the wired outlets in the box then wire and screw down each switch one at a time. Possibly safer too. I'm sure it's fine.

    As far as stingy on the wire...
    copper is much cheaper than fire. And I doubt home owners insurance is gonna be cool with modified electrical boxes. I'm sure you are confident that your box is good and that's all that counts just giving my two cents. not trying to sound preachy or anything. I think you made a good concept design but now maybe go spend 25 bucks and remake it better and safer.

    Tip on finding cheap romex wiring, go to a construction site where after or during wiring. Electricians often throw away short pieces due to leaving extra on a run.

    For this project 12 braided Guage copper wire used for extension cords should work great and be easy to stuff into the work boxes. Many hardware stores sell it cheap by the foot.

    Good luck with it.

    1 reply

    Reply 3 years ago

    thanks and I agree on all points, I "most likely" won't redo it, at least not anytime soon. It is going to be used just for my electronic bench. Which everything gets shut down when I'm done working there. but the heaviest amp item will be a heat shrink gun, an even that will be for a few minutes.