Introduction: DIY - 120v Electrical Switchbox

About: I'm a Nerd and a garage inventor. My dad used to say, "There he to 'The Lair' to invent something. Try not to burn the house down, OK?" I am a Graphic Designer & Illustrator from the South. I love…
For this article, I will be explaining what I did to repair my friend’s workbench electrical switch.
A friend of mine called and said that he would like for me to take a look at his power tool setup in the garage. He was concerned that the switch was no longer safe -- see attached photo!. After a brief visit and a few hours of construction time, I was ready to install a really neat replacement I made for only $5. With the flick of a knee (or by hand) he can now choose which power tool he wants to use.

I was challenged to do this without buying much of anything but a good-quality switch from RadioShack and an indicator lamp(otherwise I would have gone to the home improvement store and visited to the electrical aisle for cabling, conduit, plastic box, switch and faceplate).

Design note 1:  If I had a 3D printer, I could not only have printed a more elegant housing, but a nice broad switch lever for better accessibility.  Mounting hardware could also have been produced on the fly. A laser cutter would have made it possible to work with metals whereas that would be time consuming and difficult by hand.
Note 2: All cables and switches were verified to be rated above power requirements.

Items used:
  • RadioShack 120v Indicator Lamp with "crystal" dome lens (I used the Ruby Red item; other colors such as amber, green and blue are available)
  • RadioShack On – OFF – ON Switch (power-rated to handle the intended tool load)
  • Wood scrap
  • Saw
  • Project screws & screw gun
  • Paint
  • Vinyl lettering
  • Wood Glue

Step 1: Construction Information & Photos

Step 1: Create a Housing for the Switching Circuit
After measuring the area in which he wanted the switching unit to be placed, I created a plywood box. I used wood glue and wood screws to make an 8" x 8" x 6" box. I left off the rear cover. It is to be a removable access panel for servicing this cool contraption.

Step 2: Paint & Seal the Housing
After sanding and painting, I sealed the box with epoxy to strengthen it and prevent moisture infiltration.

Step 3: Install Switch, Indicator Lamp(s) and A/C plugs
  1. I drilled a hole and installed the switch I got from RadioShack. This switch was specifically chosen for the power-handling capability, the heavy-duty classification and the lonf flat lever for operation.
  2. I did the same to install the A/C female plugs. I drilled a hole, installed the wires & plugs and sealed them in place with epoxy or hot glue. Those were originally 8” heavy-duty wall-wart extension cables that allow you to use wall-warts without having them cover-up all of the sockets on your wall or surge protector. They were rated well above my power requirements.
  3. I drilled a hole and installed the indicator lamp as well. The lamp indicates that A/C power from the wall is present to the switch box and is ready to be switched.
  4. A master power cable (male A/C end) which brings power into the unit was also installed at this step. This was a power cable from a huge IBM eServer farm that I had left over a few years back from work.  I snipped off the unwanted end and used the remainder for the power supply cable for this unit. It was rated to properly handle the power load of the tools as well.

Step 4: Install rear panel
After installing the wiring, the switch and the indicator lamp, I performed a test to make sure it works.  Once I was satisfied, I fastened the rear panel board. 

Step 5: Apply decals and vinyl lettering
This contraption was for my buddy. I wanted to make something nice since he always gets me out of the house and invites my family to the lake where he has a houseboat and ski boat waiting for us.  Since he does nice things for us, I wanted to pimp out his tool area a little bit.  So, I designed something visually striking in Adobe Illustrator and then cut the design out with my vinyl cutter. I'm not too big into sticking vinyl lettering on every single thing (although my articles prove otherwise). But ya know, it's a tool I own and use often for my bride's crafting endeavors, so while I'm faithfully performing my duties I sneak in my own designs and labellng needs from time to time. Why not!?

Once I applied the lettering & the design, I sealed it with a protective, crystal clear spray sealant from Krylon ('WallyWorld' - $3)

Step 6: Delivery and Installation
I dropped it off and installed it onto the workbench where it is in use to this day.

He loves the ability to use his knee to switch his tools on and off.  The indicator lamp is nice as well in case he is having some power trouble with a tool and needs to know if it is a house breaker that has tripped or not. In other words, if the light is lit, then the issue is not with the power coming in (Source A/C is present and usable). If the light is lit, it also serves as a warning to not perform maintenance on the tools. You gotta unplug them or power down first.

I really hope this gives some ideas. 

— Just remember to always keep yourself safe when working with electricity. Work with one-hand when testing circuits. I suggest also that it is a great idea to never work alone (or be alone) when servicing parts or handling wires that can potentially contain dangerous voltages. It's simply not worth the risk to be out of earshot from help, if needed.  Work Safe. Work Smart.

Thanks for reading!

Step 2: What Was Done for Other Repairs

For three other repairs in this same location at a much later date, all that was necessary was to install a blue-plastic electrical box along with wiring, conduit for that wiring, a switch and faceplate. Three standalone power tools required this as their primary power switch and cable runs had deteriorated and failed. Since we had a budget for those, we simply purchased the cable, conduit, switches, boxes and faceplates so that a a single dedicated power switch box could be installed beside each tool. I still had fun building the switchbox and I think it looks a lot better than an ordinary 120V switch and faceplate.

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