How to Wire a Vacuum System for Workshop Tools

By - Summary:

Procedure for Wiring an Automatic Vacuum Control for Shop Tools: Power Tools and a Shop Vac or a House Vacuum System, Automating a Whole House Vacuum System for Shop Tools

Make a Shop Vacuum Turn On with Your Power Tools

Electrical Question: I’m building a cart that has a 12″ DeWalt chop saw, a 12″ Craftsman table saw, a DeWalt router, and a Husky 4 gallon wet and dry vacuum.

  • Ultimately the end result is to operate all of the tools at different times with the vacuum turning on when each individual item is energized. My dilemma is that I have to run three items separately and only one plug for the vacuum. The vacuum intake hoses will be run to each tool in order to minimize and control the sawdust generated.
  • My solution was to install an easily accessible switched outlet, so the toggle switch will stay in the on position, plugged into the corresponding outlet and will be energized when switched on. This switched outlet will also be run from the switched leg to a secondary outlet designated for the vacuum, so that the router and vacuum now become energized and run concurrently when switched on. The table saw will have the same configuration in a switched outlet and operate in the same fashion with the with the switched leg also ran to the one all mighty vacuum outlet. This is where the problems arise, I know in your mind you are already processing this but please let me continue. Now the chop saw is a little different in configuration due to the trigger action on the handle, for safety reasons I will not be bypassing the normal operation of this unit. It will still have a switched outlet only it will not energize the motor until the trigger is activated. The switch will energize the outlet designated for the chop saw and again the switched leg will travel to the all mighty vacuum thus turning it on.
  • Let’s recap, ultimately the goal here is to operate each piece of equipment individually and allow the switch to turn the vacuum on simultaneously. Is this possible? I already knew the outcome before configuring it because of the obvious reasons. The three separate switched outlets function as desired, although when the three switched legs are connected to the all mighty vacuum receptacle together it creates the loop that alternating current was originally designed to function. The chop saw, table saw, and router all work in this configuration, the problem is that when any of the three are switched on it makes that circle of energy come to life and energizes the other two units. Is there a relay or another way to do this without energizing everything. If you require more information, gladly I can send you everything I have. Actually there is another question about amps that is of concern as well with this project. I am installing a retractable extension cord on this cart as well to just make an easy permanent source of providing power to the cart. I was hoping to simply use a 110v power cord that is equipped with 14gauge wire and a 13amp internal circuit breaker. Normal usage would be that only one piece of equipment and the vacuum will be turned on at the same time. Thanks again, can’t wait to hear what you think.

Dave, I am in no means an electrician by trade and have an immense amount of respect for the knowledge that you and all of your electrical bothers encompass There is much to know and if done incorrectly, the end result could very well be catastrophic. In advance I’d like to say thanks for taking a look at this and doing your best to help me.

This home electrical wiring question came from: Paul, in Thousand Oaks, California.

Additional Comments: I really enjoyed reading the website because it was informative. There are many other websites to submit questions similar to yours, only thing is that this one was the only one I wanted to spend the time writing this novel to due to the previous questions and answers provided by others. Thanks for providing this service to me and everyone who is electrically challenged as myself.

Dave’s Reply:
Thanks for your electrical wiring question Paul.
I have wired a few workshops and I think I know exactly what you are looking for, and I will describe this process below.

Procedure for Wiring an Automatic Vacuum Control for Shop Tools

  1. Power Tools and a Shop Vac or a House Vacuum System

    • If the tools are being supplied with power from one circuit and you would like the vacuum unit to automatically turn on when any tool is being used then you should be able to use a “CT” with a set of contacts for this function.
  2. Current Transformer Controlled Vacuum System

    • A CT is a Current Transformer which clamps over the hot wire of the circuit and will close the contacts when a set parameter is met, in this case a minimum level of amperage for the smallest tool.
    • The CTs come in a variety of sizes and you will most likely need to wire a low voltage control circuit through the CT contacts because the contacts may not be rated for the current draw of your shop vac.
  3. Automatic Vacuum System Control Circuit for a Shop Vac

    • The control circuit could be 24 volts consisting of a 24 volt transformer, low voltage wire, 24 volt relay with contacts rated for  a 120 volt shop vac rated at 15 to 20 amps.
    • This control circuit would be used turn the shop vac system on and off when a shop tool is turned on which has circuit power that is monitored by the CT.
  4. Automating a Whole House Vacuum System for Shop Tools

    • A whole house vacuum system operates using the same basic design where a low voltage relay is used to activate the vacuum motor except the system turns on when the metal end of the vacuum hose is inserted into a vacuum receptacle.
    • To connect into the whole house vacuum system  just intercept the low voltage control  wiring and connect it through the CT contact.
  5. An Alternative Power Tool and Shop Vacuum Control System

    • If you don’t want to use CTs then consider using a double pole switch to activate each power tool.
    • One side or pole of the switch can be used for the 120 volt power to the tool, and the other pole or side of the switch can be used for the 24 volt control circuit or the 120 volt circuit wiring to the receptacle for the shop vac.
  6. Vacuum System Vent Control

    • The only thing left to work out is how to open and close the vents for the vacuum system so you will maintain a good level of vacuum. Possibly using the same method only using one CT for each tool, the CTs may be wired so any one will turn on the vacuum, however a port switcher may be positioned for the correct port for the vacuum. (that’s just a thought off the top of my head)
    • With control sensors and devices you can make just about anything work, that’s why I love working with automation and controls.

More about Wiring Control Relay

All About Electrical Relays

  • Understanding Electrical Relays

  • The use of relays that are sometimes needed to control special device loads such as Air Conditioners and other high demand equipment from starting at the same time.


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One Response to “How to Wire a Vacuum System for Workshop Tools”
  1. Ron Angone says:

    Where can I obtain a parts list and wiring diagram?


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